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Question 1
Incorrect
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A 32-year-old man comes to the clinic with a maculopapular rash and mouth ulcers. He had a painless penile ulcer two months ago. What is the most probable causative organism for his symptoms?
Your Answer: Herpes simplex virus type 2
Correct Answer: Treponema pallidum
Explanation:The symptoms exhibited by this individual suggest the presence of secondary syphilis.
Understanding Syphilis: Symptoms and Stages
Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. The infection progresses through three stages: primary, secondary, and tertiary. The incubation period can range from 9 to 90 days.
During the primary stage, a painless ulcer called a chancre appears at the site of sexual contact. Local lymph nodes may also become swollen, but this symptom may not be visible in women if the lesion is on the cervix.
The secondary stage occurs 6 to 10 weeks after the primary infection and is characterized by systemic symptoms such as fevers and lymphadenopathy. A rash may appear on the trunk, palms, and soles, along with buccal ulcers and painless warty lesions on the genitalia.
In the tertiary stage, granulomatous lesions called gummas may develop on the skin and bones, and there may be an ascending aortic aneurysm. Other symptoms include general paralysis of the insane, tabes dorsalis, and Argyll-Robertson pupil.
Congenital syphilis can also occur if a pregnant woman is infected. Symptoms include blunted upper incisor teeth, linear scars at the angle of the mouth, keratitis, saber shins, saddle nose, and deafness.
Understanding the symptoms and stages of syphilis is important for early detection and treatment. It is a treatable infection, but if left untreated, it can lead to serious complications.
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This question is part of the following fields:
- Infectious Diseases
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Question 2
Correct
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A 28-year-old woman returns from a holiday in Kenya with symptoms of foul-smelling loose stools, abdominal cramps and frequent flatulence. She has had the symptoms for five days when she presents to her General Practitioner for advice. A diagnosis of giardiasis is suspected.
What would be the most useful investigation to request for this patient?Your Answer: Send stool culture for microscopy and culture (MC+S)
Explanation:Diagnostic Tests for Giardiasis: Which Ones Are Necessary?
Giardiasis is a common parasitic infection that can cause gastrointestinal symptoms such as diarrhoea, abdominal pain, and bloating. If a patient presents with these symptoms and has a history of recent foreign travel, giardiasis should be considered as a possible cause. Here are some diagnostic tests that may be ordered to confirm the diagnosis:
Stool Culture for Microscopy and Culture (MC+S)
This test is specific for detecting giardia and other potential parasitic causes of gastrointestinal symptoms. It involves sending three stool specimens 2-3 days apart to a laboratory for analysis.Colonoscopy
A colonoscopy is not necessary to diagnose giardiasis, as the patient’s symptoms and travel history are usually sufficient to suggest the diagnosis. A stool culture is a more appropriate test.Duodenal Biopsy
A duodenal biopsy is not necessary to diagnose giardiasis, as it is an invasive test that is typically reserved for investigating malabsorption, iron-deficiency anaemia, or neoplasia.Full Blood Count
A full blood count is not useful for diagnosing giardiasis, as it typically does not cause peripheral leukocytosis or eosinophilia.In summary, a stool culture for MC+S is the most appropriate test for diagnosing giardiasis in a patient with gastrointestinal symptoms and a history of recent foreign travel. Other tests, such as colonoscopy, duodenal biopsy, and full blood count, are not necessary for making the diagnosis.
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This question is part of the following fields:
- Infectious Diseases
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Question 3
Correct
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A 35-year-old HIV positive man comes to your travel clinic seeking advice on vaccinations for his upcoming trip. He is currently on antiretroviral therapy and his most recent CD4 count is 180 cells/mm³. He has no other medical conditions and is feeling well.
Which vaccines should be avoided in this individual?Your Answer: Tuberculosis (BCG)
Explanation:Patients who are HIV positive should not receive live attenuated vaccines like BCG. Additionally, immunocompromised individuals should avoid other live attenuated vaccines such as yellow fever, oral polio, intranasal influenza, varicella, and measles, mumps, and rubella (MMR). This information is sourced from uptodate.
Types of Vaccines and Their Characteristics
Vaccines are essential in preventing the spread of infectious diseases. However, it is crucial to understand the different types of vaccines and their characteristics to ensure their safety and effectiveness. Live attenuated vaccines, such as BCG, MMR, and oral polio, may pose a risk to immunocompromised patients. In contrast, inactivated preparations, including rabies and hepatitis A, are safe for everyone. Toxoid vaccines, such as tetanus, diphtheria, and pertussis, use inactivated toxins to generate an immune response. Subunit and conjugate vaccines, such as pneumococcus, haemophilus, meningococcus, hepatitis B, and human papillomavirus, use only part of the pathogen or link bacterial polysaccharide outer coats to proteins to make them more immunogenic. Influenza vaccines come in different types, including whole inactivated virus, split virion, and sub-unit. Cholera vaccine contains inactivated strains of Vibrio cholerae and recombinant B-subunit of the cholera toxin. Hepatitis B vaccine contains HBsAg adsorbed onto aluminium hydroxide adjuvant and is prepared from yeast cells using recombinant DNA technology. Understanding the different types of vaccines and their characteristics is crucial in making informed decisions about vaccination.
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This question is part of the following fields:
- Infectious Diseases
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Question 4
Correct
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The organism that is becoming increasingly resistant to antimicrobial agents and is responsible for a high number of hospital-acquired infections is which of the following?
Your Answer: Staphylococcus aureus
Explanation:Common Pathogens and Their Associated Infections
Hospital-acquired infections can be caused by various pathogens, including viruses, bacteria, and fungi. The most common types of infections are bloodstream infection, pneumonia, urinary tract infection, and surgical site infection. Staphylococcus aureus is a prevalent pathogen, with approximately 33% of the general population being carriers and 2% carrying the antibiotic-resistant strain MRSA. Toxoplasma gondii can cause severe disease in fetuses, newborns, and immunocompromised patients. Streptococcus pneumoniae is a leading cause of pneumonia and meningitis in children and the elderly, as well as septicaemia in HIV-infected individuals. Pneumocystis jiroveci is a rare cause of infection in the general population but can cause pneumonia in immunocompromised patients, especially those with AIDS. Listeria monocytogenes primarily affects newborns, elderly patients, and immunocompromised individuals. Understanding these common pathogens and their associated infections is crucial in preventing and treating hospital-acquired infections.
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This question is part of the following fields:
- Infectious Diseases
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Question 5
Correct
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Before his initial occupational health visit, the clinic physician reviews the results of a blood test taken by a 23-year-old medical student for hepatitis B serology.
What is the significance of the following blood test results?
- Positive anti-HBc IgG
- Negative anti-HBc IgM
- Negative anti-HBs
- Positive HBsAgYour Answer: Chronic infection with hepatitis B
Explanation:If a person has a positive anti-HBc IgG, negative anti-HBc IgM, and negative anti-HBc in the presence of HBsAg, it indicates that they have a chronic hepatitis B infection. In acute hepatitis B infection, HBsAg is usually the first positive marker, and if it remains positive for over 6 months, the patient has a chronic hepatitis B infection. The presence of HBsAg in this patient indicates either acute or chronic infection with hepatitis B. In response to infection, the body produces antibodies to the hepatitis B core antibody (anti-HBc), which remain indefinitely. In acute infection, IgM antibodies are produced, which are gradually replaced with IgG antibodies. This patient has negative anti-HBc IgM and positive anti-HBc IgG, indicating no acute infection. The absence of anti-HBs confirms chronic infection. In acute infection, anti-HBc IgM would also be positive, indicating exposure to the virus within the last 6 months. Over time, this is replaced with anti-HBc IgG, indicating resolved or chronic infection. Immunity following previous infection would be positive for anti-HBc IgG and anti-HBs, while previous vaccination would show positive anti-HBs only.
Interpreting hepatitis B serology is an important skill that is still tested in medical exams. It is crucial to keep in mind a few key points. The surface antigen (HBsAg) is the first marker to appear and triggers the production of anti-HBs. If HBsAg is present for more than six months, it indicates chronic disease, while its presence for one to six months implies acute disease. Anti-HBs indicates immunity, either through exposure or immunization, and is negative in chronic disease. Anti-HBc indicates previous or current infection, with IgM anti-HBc appearing during acute or recent hepatitis B infection and persisting IgG anti-HBc. HbeAg is a marker of infectivity and HBV replication.
To illustrate, if someone has been previously immunized, their anti-HBs will be positive, while all other markers will be negative. If they had hepatitis B more than six months ago but are not a carrier, their anti-HBc will be positive, and HBsAg will be negative. However, if they are now a carrier, both anti-HBc and HBsAg will be positive. If HBsAg is present, it indicates an ongoing infection, either acute or chronic if present for more than six months. On the other hand, anti-HBc indicates that the person has caught the virus, and it will be negative if they have been immunized.
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This question is part of the following fields:
- Infectious Diseases
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Question 6
Correct
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A 63-year-old woman is admitted to the medical ward with a 4-week history of fevers and lethargy. During the examination, you observe a few splinter haemorrhages in the fingernails and a loud systolic murmur at the apex. Your consultant advises you to obtain 3 sets of blood cultures and to schedule an echocardiogram. Microbiology contacts you later that day with the preliminary blood culture findings.
What organism is the most probable cause of the growth?Your Answer: Gram positive cocci
Explanation:Gram positive cocci are responsible for the majority of bacterial endocarditis cases. The most common culprits include Streptococcus viridans, Staphylococcus aureus (in individuals who use intravenous drugs or have prosthetic valves), and Staphylococcus epidermidis (in those with prosthetic valves). Other less common causes include Enterococcus, Streptococcus bovis, Candida, HACEK group, and Coxiella burnetii. Acute endocarditis is typically caused by Staphylococcus, while subacute cases are usually caused by Streptococcus species. Knowing the common underlying organisms is crucial for determining appropriate empirical antibiotic therapy. For native valve endocarditis, amoxicillin and gentamicin are recommended. Vancomycin and gentamicin are recommended for NVE with severe sepsis, penicillin allergy, or suspected methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin and meropenem are recommended for NVE with severe sepsis and risk factors for gram-negative infection. For prosthetic valve endocarditis, vancomycin, gentamicin, and rifampicin are recommended. Once blood culture results are available, antibiotic therapy can be adjusted to provide specific coverage. Treatment typically involves long courses (4-6 weeks) of intravenous antibiotic therapy.
Aetiology of Infective Endocarditis
Infective endocarditis is a condition that affects patients with previously normal valves, rheumatic valve disease, prosthetic valves, congenital heart defects, intravenous drug users, and those who have recently undergone piercings. The strongest risk factor for developing infective endocarditis is a previous episode of the condition. The mitral valve is the most commonly affected valve.
The most common cause of infective endocarditis is Staphylococcus aureus, particularly in acute presentations and intravenous drug users. Historically, Streptococcus viridans was the most common cause, but this is no longer the case except in developing countries. Streptococcus mitis and Streptococcus sanguinis are the two most notable viridans streptococci, commonly found in the mouth and dental plaque. Coagulase-negative Staphylococci such as Staphylococcus epidermidis are the most common cause of endocarditis in patients following prosthetic valve surgery.
Streptococcus bovis is associated with colorectal cancer, with the subtype Streptococcus gallolyticus being most linked to the condition. Non-infective causes of endocarditis include systemic lupus erythematosus and malignancy. Culture negative causes may be due to prior antibiotic therapy or infections caused by Coxiella burnetii, Bartonella, Brucella, or HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella).
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This question is part of the following fields:
- Infectious Diseases
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Question 7
Correct
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An 80-year-old man presents with a 2-week history of profuse loose stools and severe abdominal pain over the past 2 days. He has lost his appetite and is only tolerating small amounts of fluid over the past 24 hours. On examination, his heart rate is 118 bpm, respiratory rate is 22 breaths/min, temperature 38.1ºC and blood pressure is 104/74 mmHg. Significant left iliac fossa tenderness is noted. The patient is urgently admitted, and a stool culture confirms Clostridium difficile infection and severe colitis without perforation on imaging. What is the most appropriate treatment for this patient?
Your Answer: Oral vancomycin AND IV metronidazole
Explanation:The treatment for life-threatening C. difficile infection involves administering vancomycin orally and metronidazole intravenously.
Clostridioides difficile is a type of bacteria that is commonly found in hospitals. It is a Gram positive rod that produces an exotoxin which can cause damage to the intestines, leading to a condition called pseudomembranous colitis. This bacteria usually develops when the normal gut flora is suppressed by broad-spectrum antibiotics, with second and third generation cephalosporins being the leading cause of C. difficile. Other risk factors include proton pump inhibitors. Symptoms of C. difficile include diarrhea, abdominal pain, and a raised white blood cell count. The severity of the infection can be determined using the Public Health England severity scale, which ranges from mild to life-threatening.
To diagnose C. difficile, a stool sample is tested for the presence of C. difficile toxin (CDT). Treatment for a first episode of C. difficile infection typically involves oral vancomycin for 10 days, with fidaxomicin or a combination of oral vancomycin and IV metronidazole being used as second and third-line therapies. Recurrent infections occur in around 20% of patients, increasing to 50% after their second episode. In such cases, oral fidaxomicin is recommended within 12 weeks of symptom resolution, while oral vancomycin or fidaxomicin can be used after 12 weeks. For life-threatening C. difficile infections, oral vancomycin and IV metronidazole are used, and surgery may be considered with specialist advice. Other therapies, such as bezlotoxumab and fecal microbiota transplant, may also be considered for preventing recurrences in certain cases.
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This question is part of the following fields:
- Infectious Diseases
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Question 8
Incorrect
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A 32-year-old woman who lives with her husband comes to you for advice. She has been experiencing anal discharge and itching for the past 4 days. She also has some symptoms of painful urination. A urethral smear shows intracellular diplococci.
What is the most probable infectious agent that matches this clinical presentation?Your Answer: Treponema pallidum
Correct Answer: Neisseria gonorrhoeae
Explanation:Common Sexually Transmitted Infections and Diagnostic Methods
Sexually transmitted infections (STIs) are a major public health concern worldwide. Here are some common STIs and their diagnostic methods:
Neisseria gonorrhoeae: This bacterium causes gonorrhoea, which is a purulent infection of the mucous membranes. In men, symptoms include urethritis, acute epididymitis, and rectal infection. A Gram stain is the method of choice for detecting gonorrhoea in symptomatic men.
Treponema pallidum: This spirochaete bacterium causes syphilis. Serologic testing is the standard method of detection for all stages of syphilis.
Chlamydia trachomatis: This bacterium is an obligate intracellular micro-organism that infects squamocolumnar epithelial cells. Nucleic acid amplification testing (NAAT) is the most sensitive test for detecting C. trachomatis infection, and a urine sample is an effective specimen for this test.
Herpes simplex virus type 1 (HSV-1): This virus is typically associated with orofacial disease. Tissue culture isolation and immunofluorescent staining can be used to diagnose HSV-1.
Herpes simplex virus type 2 (HSV-2): This virus is typically associated with urogenital disease. Tissue culture isolation and immunofluorescent staining can be used to diagnose HSV-2.
Common STIs and Their Diagnostic Methods
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This question is part of the following fields:
- Infectious Diseases
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Question 9
Incorrect
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A 25-year-old student presents to the Emergency Department with confusion and recurring fevers. He describes a flu-like illness in recent days, with myalgia and rigours every two days. He has previously been well, other than an episode of suspected malaria on a gap year in Brazil three years ago, which was felt to be successfully treated. He has not been abroad since.
On examination, he has splenomegaly, scleral icterus and a temperature of 39.1°C.
Investigations reveal the following:
Investigation Result Normal value
Haemoglobin (Hb) 95 g/l 135–175 g/l
White Cell Count (WCC) 14 × 109/l 4.0–11.0 × 109/l
Platelets (PLT) 100 × 109 150–450× 109/l
Blood film Awaited
Which of the following is the most likely causative organism?Your Answer: Plasmodium malariae
Correct Answer: Plasmodium vivax
Explanation:Differential Diagnosis for a Patient with Fluctuating Pyrexia: Malaria vs. Other Causes
The patient in question is experiencing fluctuating rigours of malaria, despite not having been in a malaria-affected zone for two years. This suggests a recurrence of pre-existing malaria, with the most likely subtype being P. vivax due to its ability to lie dormant in the liver for extended periods. While dengue fever is a possibility, the history of fluctuating pyrexia is more indicative of malaria, which also causes anaemia and thrombocytopenia. P. falciparum is a reasonable differential, but less likely given the patient’s travel history. P. malariae is rare and typically presents with fevers recurring every three days, making it less likely. Yellow fever is also unlikely due to the patient’s travel timeline and lack of jaundice. Overall, malaria is the most likely cause of the patient’s symptoms.
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This question is part of the following fields:
- Infectious Diseases
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Question 10
Incorrect
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Sarah is a 44-year-old hairdresser who contacts her GP due to a 2-day history of cough and fever. Her Covid-19 test is negative and she does not sound breathless on the phone. Sarah has been taking paracetamol regularly but despite this, she is still feeling feverish; she has recorded her temperature as 37.8ºC. She has a past medical history of eczema, gilbert's syndrome and adrenal insufficiency. She takes hydrocortisone 15 mg in the morning and 10mg at lunchtime, and also takes fludrocortisone 200 micrograms once a day.
What is the most appropriate management plan for Sarah?Your Answer: Double the dose of both his hydrocortisone and fludrocortisone
Correct Answer: Double the dose of his hydrocortisone
Explanation:To manage an Addison’s patient with an intercurrent illness, it is recommended to double the dose of their glucocorticoids, specifically hydrocortisone, while keeping the fludrocortisone dose the same. This is because the patient’s fever >37.5 indicates a moderate intercurrent illness. Continuing paracetamol regularly is not the main priority in this situation. Advising the patient to call 999 for admission is unnecessary unless there are severe symptoms such as vomiting or persistent diarrhea. Doubling the dose of fludrocortisone is not recommended as it is a mineralocorticoid with weak glucocorticoid activity, and increasing the glucocorticoid is necessary to mimic a stress response.
Addison’s disease is a condition that requires patients to undergo both glucocorticoid and mineralocorticoid replacement therapy. This treatment usually involves taking a combination of hydrocortisone and fludrocortisone. Hydrocortisone is typically given in 2 or 3 divided doses, with patients requiring 20-30 mg per day, mostly in the first half of the day. Patient education is crucial, and it is essential to emphasize the importance of not missing glucocorticoid doses. Additionally, patients should consider wearing MedicAlert bracelets and steroid cards, and they should be provided with hydrocortisone for injection with needles and syringes to treat an adrenal crisis.
During an intercurrent illness, it is crucial to manage the glucocorticoid dose properly. In simple terms, the glucocorticoid dose should be doubled, while the fludrocortisone dose should remain the same. The Addison’s Clinical Advisory Panel has produced guidelines that detail specific scenarios, and patients should refer to these guidelines for more information. It is essential to discuss how to adjust the glucocorticoid dose during an intercurrent illness with a healthcare professional. Proper management of Addison’s disease is crucial to ensure that patients can lead healthy and fulfilling lives.
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This question is part of the following fields:
- Infectious Diseases
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Question 11
Incorrect
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A 26-year-old male patient complains of painful ulcers on his penis shaft and dysuria for the past three days. He has never experienced such symptoms before. The clinical diagnosis suggests primary genital herpes. What is the best course of action for managing this condition?
Your Answer: Topical valaciclovir
Correct Answer: Oral aciclovir
Explanation:Even if the presentation is delayed for up to 5 days, primary genital herpes infections require oral antiviral therapy.
Understanding Herpes Simplex Virus
Herpes simplex virus (HSV) is a common viral infection that affects humans. There are two strains of the virus, HSV-1 and HSV-2, which were previously thought to cause oral and genital herpes, respectively. However, there is now considerable overlap between the two strains. The primary infection may present with severe gingivostomatitis, while cold sores and painful genital ulceration are common features.
Management of HSV includes oral aciclovir for gingivostomatitis and genital herpes, and topical aciclovir for cold sores, although the evidence base for the latter is modest. Patients with frequent exacerbations may benefit from longer-term aciclovir. In pregnant women, a primary attack of herpes during pregnancy at greater than 28 weeks gestation may require elective caesarean section at term. Women with recurrent herpes who are pregnant should be treated with suppressive therapy and advised that the risk of transmission to their baby is low.
The cytopathic effect of HSV can be seen in Pap smears, which show multinucleated giant cells representing infection by the virus. The 3 M’s – multinucleation, margination of the chromatin, and molding of the nuclei – are characteristic features of HSV infection. Understanding the features and management of HSV is important for effective treatment and prevention of transmission.
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This question is part of the following fields:
- Infectious Diseases
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Question 12
Correct
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A 28-year-old woman complains of a yellowish-green vaginal discharge that began two weeks ago. During examination, her vagina appears swollen and red.
What is the most probable diagnosis?Your Answer: Trichomoniasis
Explanation:Common Genitourinary Infections: Symptoms and Diagnosis
Trichomoniasis, Candidiasis, AIDS, HPV, and Lactobacilli infection are some of the most common genitourinary infections. Trichomoniasis is caused by Trichomonas vaginalis and presents with abnormal vaginal discharge, odour, itching, burning, soreness, and dyspareunia. Candidiasis is a fungal infection caused by yeasts from the genus Candida and presents with pruritus, vaginal discharge, dysuria, and dyspareunia. AIDS is a viral infection that has a hyperacute onset and is unlikely in patients with no past medical history or risk factors. HPV infection is common and often goes unnoticed, but can manifest as warty lesions on the genital or anal area. Lactobacilli infection is not associated with causing infection. Diagnosis of these infections depends on laboratory testing, with culture being the current criterion standard for trichomoniasis and physical examination for candidiasis.
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This question is part of the following fields:
- Infectious Diseases
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Question 13
Correct
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A 25-year-old student presents to his General Practitioner with a 10-day history of fever and sore throat. He recently completed a course of amoxicillin despite developing a rash a few days into the course. On examination, he is febrile and his tonsils are inflamed but no exudate is present; there are petechial spots on his palate and he has a widespread maculopapular rash, cervical lymphadenopathy and splenomegaly.
Which of the following is the most likely diagnosis?
Your Answer: Infectious mononucleosis
Explanation:Differential Diagnosis of a Patient with Sore Throat and Fever
Infectious mononucleosis, also known as glandular fever, is a common cause of sore throat and fever in adolescents. It is caused by the Epstein-Barr virus and presents with symptoms such as sore throat, fever, and lethargy. The duration of symptoms is longer than other causes of acute sore throat, and examination findings may include lymphadenopathy and splenomegaly. Palatal petechiae is a distinguishing feature between glandular fever and streptococcal tonsillitis. A maculopapular rash may also be present, but it is important to note that amoxicillin can cause a rash in patients with glandular fever. Stevens-Johnson syndrome, bacterial tonsillitis, candidiasis, and mumps are other possible differential diagnoses. However, Stevens-Johnson syndrome is a severe mucocutaneous reaction to medications or infections, bacterial tonsillitis presents with enlarged, inflamed tonsils with exudate and cervical lymphadenopathy, candidiasis presents with white coating of buccal membranes, throat, or tongue, and mumps presents with bilateral parotid gland enlargement. Therefore, based on the patient’s history and examination findings, infectious mononucleosis is the most likely diagnosis.
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This question is part of the following fields:
- Infectious Diseases
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Question 14
Correct
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You are asked to review an elderly nursing home resident who has generalised inflammation of his oropharynx and is finding it difficult to eat. His past history of note includes the use of a steroid inhaler for chronic obstructive pulmonary disease (COPD). On examination, there are areas of erythema and a number of white plaques accompanied by some white, curd-like material.
Which diagnosis best fits this clinical picture?Your Answer: Oropharyngeal candidiasis
Explanation:Differential Diagnosis of Oral Lesions: Candidiasis, HIV Infection, Hairy Leukoplakia, Darier’s Disease, and Leukoedema
Oral lesions can present in various forms and have different underlying causes. In the case of an elderly man with long-term use of a steroid inhaler for COPD, poor oral hygiene, and possibly poorly fitting prosthetics, the most likely diagnosis is oropharyngeal candidiasis. This yeast-like fungal infection can be treated with antifungal medication, applied to the oral mucosa and any removable oral prostheses, and soaking the latter in an antifungal denture-soaking solution.
HIV infection can also cause oral lesions, primarily in patients with advanced disease. Candidiasis is a common opportunistic infection in these patients, but hairy leukoplakia, associated with Epstein-Barr virus, can also occur. Hairy leukoplakia presents as painless white lesions on the tongue or buccal mucosa, with a characteristic hairy appearance that cannot be scraped off.
Darier’s disease is a rare genetic disorder that causes greasy hyperkeratotic papules in seborrhoeic regions, nail abnormalities, and mucous membrane changes. Mucosal lesions are found in approximately 15% of patients, appearing as white papules with a central depression, most commonly in the mouth.
Leukoedema is a benign condition characterized by a blue, grey, or white appearance of the oral mucosa, with wrinkled, streaky lesions, mostly found on the inside of the cheeks. It is more common and pronounced in smokers.
In summary, the differential diagnosis of oral lesions includes candidiasis, HIV infection, hairy leukoplakia, Darier’s disease, and leukoedema. A thorough examination and consideration of the patient’s medical history can help determine the underlying cause and appropriate treatment.
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This question is part of the following fields:
- Infectious Diseases
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Question 15
Correct
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You are working in the sexual health clinic. A 26-year-old male presents with dysuria and urethral discharge. He had unprotected sexual intercourse 3 weeks ago. You do a full sexual health screen. Three days later he returns to get his results; the initial test is positive for Neisseria gonorrhoea, sensitivities are not known.
What is the most suitable course of action?Your Answer: Intramuscular ceftriaxone
Explanation:Understanding Gonorrhoea: Causes, Symptoms, Microbiology, and Management
Gonorrhoea is a sexually transmitted infection caused by the Gram-negative diplococcus Neisseria gonorrhoeae. It can occur on any mucous membrane surface, including the genitourinary tract, rectum, and pharynx. The incubation period of gonorrhoea is typically 2-5 days. Symptoms in males include urethral discharge and dysuria, while females may experience cervicitis leading to vaginal discharge. Rectal and pharyngeal infections are usually asymptomatic.
Immunisation against gonorrhoea is not possible, and reinfection is common due to antigen variation of type IV pili and Opa proteins. Local complications may develop, including urethral strictures, epididymitis, and salpingitis, which can lead to infertility. Disseminated infection may also occur, with gonococcal infection being the most common cause of septic arthritis in young adults.
Management of gonorrhoea involves the use of antibiotics. Ciprofloxacin used to be the treatment of choice, but there is now increased resistance to it. Cephalosporins are now more widely used, with a single dose of IM ceftriaxone 1g being the new first-line treatment. If ceftriaxone is refused, oral cefixime 400mg + oral azithromycin 2g should be used. Disseminated gonococcal infection (DGI) and gonococcal arthritis may also occur, with symptoms including tenosynovitis, migratory polyarthritis, and dermatitis. Later complications include septic arthritis, endocarditis, and perihepatitis.
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This question is part of the following fields:
- Infectious Diseases
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Question 16
Correct
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A 29-year-old man who has recently arrived in the UK from Uganda visits the clinic with complaints of exhaustion and purple skin lesions all over his body. During the examination, you observe multiple raised purple lesions on his trunk and arms. Additionally, you notice some smaller purple lesions in his mouth. He has recently initiated acyclovir treatment for herpes zoster infection. What is the probable diagnosis?
Your Answer: Kaposi's sarcoma
Explanation:The presence of raised purple lesions is a typical indication of Kaposi’s sarcoma, which may suggest that the patient has an underlying HIV infection. Given the high prevalence of HIV in Uganda and the recent occurrence of herpes zoster, it is possible that the patient’s immune system is compromised. Dermatofibromas, which are typically small and firm, would not be found in the mouth, while psoriasis is characterized by red, scaly lesions that do not appear on mucosal surfaces. A drug reaction is an unlikely explanation for the patient’s symptoms. Although a haemangioma can present as a purple raised lesion, it is uncommon to find them in the mouth, and Kaposi’s sarcoma is a more likely diagnosis in this case.
Kaposi’s Sarcoma in HIV Patients
Kaposi’s sarcoma is a type of cancer that is commonly seen in patients with HIV. It is caused by the human herpes virus 8 (HHV-8) and is characterized by the appearance of purple papules or plaques on the skin or mucosa. These lesions may later ulcerate, causing discomfort and pain. In some cases, respiratory involvement may occur, leading to massive haemoptysis and pleural effusion.
Treatment for Kaposi’s sarcoma typically involves a combination of radiotherapy and resection. This can help to reduce the size of the lesions and prevent further spread of the cancer. However, it is important to note that Kaposi’s sarcoma can be a serious and potentially life-threatening condition, particularly in patients with HIV. As such, it is important for individuals with HIV to be regularly screened for this condition and to seek prompt medical attention if any symptoms are present.
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This question is part of the following fields:
- Infectious Diseases
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Question 17
Incorrect
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A 50-year-old man residing in the UK has been diagnosed with pulmonary tuberculosis and his sputum test is positive for acid-fast bacilli. He has a medical history of hypertension and takes bendroflumethiazide and amlodipine. What is the recommended initial medication combination for him?
Your Answer: Rifampicin, isoniazid, pyrazinamide, ethambutol and streptomycin
Correct Answer: Rifampicin, isoniazid, pyrazinamide and ethambutol
Explanation:Managing Tuberculosis: Treatment and Complications
Tuberculosis is a serious infectious disease that requires prompt and effective treatment. The standard therapy for active tuberculosis involves an initial phase of two months, during which patients are given a combination of four drugs: rifampicin, isoniazid, pyrazinamide, and ethambutol. The continuation phase lasts for four months and involves the use of rifampicin and isoniazid. Patients with latent tuberculosis are typically treated with a combination of isoniazid and rifampicin for three or six months, depending on the severity of the infection.
In some cases, patients may require prolonged treatment, particularly if they have meningeal tuberculosis. Steroids may be added to the treatment regimen in these cases. Directly observed therapy may also be necessary for certain groups, such as homeless individuals, prisoners, and patients who are likely to have poor concordance.
While tuberculosis treatment is generally effective, there are some potential complications to be aware of. Immune reconstitution disease can occur several weeks after starting treatment and may present with enlarging lymph nodes. Drug adverse effects are also possible, with rifampicin being a potent liver enzyme inducer and isoniazid causing peripheral neuropathy. Pyrazinamide can cause hyperuricaemia and ethambutol may lead to optic neuritis, so it is important to monitor patients closely for any signs of adverse effects. Overall, with proper management and monitoring, tuberculosis can be successfully treated.
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This question is part of the following fields:
- Infectious Diseases
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Question 18
Incorrect
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A 5-day-old infant presents with congenital cataracts, sensorineural deafness, and pulmonary artery stenosis. What is the probable prenatal infection that the baby has been exposed to?
Your Answer: Cytomegalovirus
Correct Answer: Rubella
Explanation:The neonate is diagnosed with congenital rubella syndrome, which is characterized by sensorineural deafness, eye abnormalities, and congenital heart disease. The risk of fetal infection is highest if the mother contracts the virus during the first trimester of pregnancy. Antenatal cytomegalovirus infection can lead to cerebral calcification, microcephaly, and sensorineural deafness. HIV does not pose a physical risk to the developing fetus, but there is a risk of perinatal transmission. Parvovirus B19 can cause hydrops fetalis and fetal death. Toxoplasmosis can result in intracranial calcification, hydrocephalus, and epilepsy in the affected child.
Rubella and Pregnancy: Risks, Features, Diagnosis, and Management
Rubella, also known as German measles, is a viral infection caused by the togavirus. Thanks to the introduction of the MMR vaccine, it is now rare. However, if contracted during pregnancy, there is a risk of congenital rubella syndrome, which can cause serious harm to the fetus. It is important to note that the incubation period is 14-21 days, and individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash.
The risk of damage to the fetus is highest in the first 8-10 weeks of pregnancy, with a risk as high as 90%. However, damage is rare after 16 weeks. Features of congenital rubella syndrome include sensorineural deafness, congenital cataracts, congenital heart disease (e.g. patent ductus arteriosus), growth retardation, hepatosplenomegaly, purpuric skin lesions, ‘salt and pepper’ chorioretinitis, microphthalmia, and cerebral palsy.
If a suspected case of rubella in pregnancy arises, it should be discussed immediately with the local Health Protection Unit (HPU) as type/timing of investigations may vary. IgM antibodies are raised in women recently exposed to the virus. It should be noted that it is very difficult to distinguish rubella from parvovirus B19 clinically. Therefore, it is important to also check parvovirus B19 serology as there is a 30% risk of transplacental infection, with a 5-10% risk of fetal loss.
If a woman is tested at any point and no immunity is demonstrated, they should be advised to keep away from people who might have rubella. Non-immune mothers should be offered the MMR vaccination in the post-natal period. However, MMR vaccines should not be administered to women known to be pregnant or attempting to become pregnant.
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This question is part of the following fields:
- Infectious Diseases
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Question 19
Correct
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If you sustain a needlestick injury while taking blood from a patient suspected of having human immunodeficiency virus (HIV), what should be your first course of action?
Your Answer: Wash wound under running water, encouraging active bleeding
Explanation:Immediate Actions to Take Following a Needlestick Injury: A Guide for Healthcare Workers
Needlestick injuries are a common occupational hazard for healthcare workers. If you experience a needlestick injury, it is important to take immediate action to minimize the risk of infection. Here are the steps you should take:
1. Wash the wound thoroughly under running water, while encouraging bleeding. This will help to flush out any pathogens that may be present.
2. Determine the patient’s HIV and bloodborne disease status. If the patient is HIV-positive or deemed to be at high risk, HIV post-exposure prophylaxis (PEP) should be offered as soon as possible.
3. Begin Truvada and Kaletra PEP treatment if the patient is definitely HIV-positive or deemed to be at high risk. PEP should be commenced within 72 hours of exposure for maximum effectiveness.
4. Contact occupational health immediately to identify local protocols and receive guidance on next steps.
5. Fill out a clinical incident form to help the hospital identify potential areas for improvement in employee safety.
By following these steps, you can minimize the risk of infection and protect your health as a healthcare worker.
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This question is part of the following fields:
- Infectious Diseases
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Question 20
Incorrect
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A 31-year-old female patient visits her doctor with complaints of feeling unwell for the past week. She reports experiencing headaches and mild abdominal discomfort. She denies having any diarrhea but mentions severe constipation. Recently, she returned from a 3-week trip to India. During the examination, her temperature is recorded as 38.5ºC, and she appears bloated. Additionally, a sparse macular rash is observed on her chest. What is the probable causative agent for this presentation?
Your Answer: Shigella sonnei
Correct Answer: Salmonella typhi
Explanation:While salmonella can cause diarrhoea, typhoid fever is more likely to result in constipation. This is a typical symptom of typhoid fever, along with the appearance of rose spots. It’s important to note that constipation can be a significant indicator of this illness. In contrast, Campylobacter jejuni infection usually causes bloody diarrhoea and abdominal pain. E. coli is a common cause of watery diarrhoea, but certain strains like E. coli O157:H7 can lead to severe abdominal cramping, vomiting, and bloody diarrhoea. Giardiasis can cause similar symptoms such as bloating and abdominal pain, but it usually results in chronic diarrhoea. Shigellosis typically causes abdominal pain and diarrhoea, which may or may not be bloody.
Enteric fever, also known as typhoid or paratyphoid, is caused by Salmonella typhi and Salmonella paratyphi respectively. These bacteria are not normally found in the gut and are transmitted through contaminated food and water or the faecal-oral route. The symptoms of enteric fever include headache, fever, and joint pain, as well as abdominal pain and distension. Constipation is more common in typhoid than diarrhoea, and rose spots may appear on the trunk in some patients. Complications can include osteomyelitis, gastrointestinal bleeding or perforation, meningitis, cholecystitis, and chronic carriage. Chronic carriage is more likely in adult females and occurs in approximately 1% of cases.
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This question is part of the following fields:
- Infectious Diseases
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Question 21
Incorrect
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A 19-year-old non-pregnant, asymptomatic woman with no past medical history is found to have 106 colony-forming units of Escherichia coli/ml of urine on a routine health check.
Which of the following is the most appropriate management?
Your Answer: Treat with oral co-trimoxazole for 10 days
Correct Answer: No antibiotics are indicated
Explanation:Management of Asymptomatic Bacteriuria
Asymptomatic bacteriuria is a common finding in clinical practice, but it does not require antibiotic treatment. Patients with asymptomatic bacteriuria are at increased risk for symptomatic UTI, but treatment does not decrease the frequency of symptomatic UTIs nor improve other outcomes. Therefore, screening for or treatment of asymptomatic bacteriuria is not appropriate and should be discouraged.
Treatment of asymptomatic bacteriuria in women should be reserved for pregnant patients, those undergoing a urological procedure that may produce mucosal bleeding, and the significantly immunosuppressed. Pregnant patients are considered immunosuppressed UTI hosts due to the physiological changes associated with pregnancy, which increase the risk for serious complications even in healthy pregnant women. However, it should not be treated in diabetic patients, elderly individuals, or those with indwelling catheters.
Antibiotic treatment is not recommended in this clinical scenario, even in symptomatic UTIs. Current UK antimicrobial guidance recommends treatment for 3-7 days, depending on the clinical case, not with a single-dose administration. Investigating the renal tract is also not necessary for a single finding of asymptomatic bacteriuria.
Intravenous antibiotic treatment is reserved for complicated UTIs, in which case the patient would present far more unwell than what is seen in this scenario. Underlying conditions that predispose patients to complicated UTIs include diabetes, renal failure, functional or anatomic abnormality of the urinary tract, renal transplantation, an indwelling catheter stent, or immunosuppression.
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This question is part of the following fields:
- Infectious Diseases
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Question 22
Correct
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A 65-year-old woman presents to the Emergency Department with a cough, fever, diarrhoea and myalgia. The cough is non-productive and has been getting gradually worse since she returned from holiday in Italy one week ago. Her daughter is concerned because over the past 24 hours she has become more drowsy and febrile. She is normally fit and well but drinks around 15 units of alcohol per week.
On examination, pulse is 80/min, blood pressure 110/70 mmHg, oxygen saturations are 95% on room air and temperature is 38.2ºC. Bilateral coarse crackles are heard in the chest.
Initial blood tests show the following:
Hb 13.8 g/dl
Platelets 300 * 109/l
WBC 14.5 * 109/l
Na+ 132 mmol/l
K+ 4.1 mmol/l
Urea 8.9 mmol/l
Creatinine 89 µmol/l
Bilirubin 11 µmol/l
ALP 35 u/l
ALT 62 u/l
A chest x-ray shows patchy consolidation in the right lower zone with an associated pleural effusion.
What is the most likely causative organism?Your Answer: Legionella pneumophila
Explanation:Legionella is often characterized by symptoms resembling the flu, such as a dry cough, confusion, and a slower than normal heart rate. Additionally, hyponatremia may be detected through blood tests. A history of recent travel abroad and the presence of pleural effusion are also indicative of Legionella.
Legionnaire’s Disease: Symptoms, Diagnosis, and Management
Legionnaire’s disease is a type of pneumonia caused by the Legionella pneumophilia bacterium, which is commonly found in water tanks. It is not transmitted from person to person. Symptoms of the disease include flu-like symptoms such as fever, dry cough, confusion, and lymphopaenia. Other features include relative bradycardia, hyponatraemia, and deranged liver function tests. Pleural effusion is seen in around 30% of patients.
Diagnosis of Legionnaire’s disease can be done through a urinary antigen test. Treatment involves the use of erythromycin or clarithromycin. Chest x-ray features of the disease are non-specific but may include patchy consolidation with a mid-to-lower zone predominance.
Compared to Mycoplasma pneumonia, Legionnaire’s disease has distinct differences in symptoms and diagnostic methods. It is important to be aware of the potential for Legionnaire’s disease in cases where water tanks or air-conditioning systems may be involved, as early diagnosis and treatment can lead to better outcomes.
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This question is part of the following fields:
- Infectious Diseases
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Question 23
Incorrect
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Which of the following is a live attenuated vaccine?
Your Answer: Meningococcus
Correct Answer: Mumps
Explanation:Live attenuated vaccines include BCG, MMR, oral polio, yellow fever, and oral typhoid.
Types of Vaccines and Their Characteristics
Vaccines are essential in preventing the spread of infectious diseases. However, it is crucial to understand the different types of vaccines and their characteristics to ensure their safety and effectiveness. Live attenuated vaccines, such as BCG, MMR, and oral polio, may pose a risk to immunocompromised patients. In contrast, inactivated preparations, including rabies and hepatitis A, are safe for everyone. Toxoid vaccines, such as tetanus, diphtheria, and pertussis, use inactivated toxins to generate an immune response. Subunit and conjugate vaccines, such as pneumococcus, haemophilus, meningococcus, hepatitis B, and human papillomavirus, use only part of the pathogen or link bacterial polysaccharide outer coats to proteins to make them more immunogenic. Influenza vaccines come in different types, including whole inactivated virus, split virion, and sub-unit. Cholera vaccine contains inactivated strains of Vibrio cholerae and recombinant B-subunit of the cholera toxin. Hepatitis B vaccine contains HBsAg adsorbed onto aluminium hydroxide adjuvant and is prepared from yeast cells using recombinant DNA technology. Understanding the different types of vaccines and their characteristics is crucial in making informed decisions about vaccination.
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This question is part of the following fields:
- Infectious Diseases
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Question 24
Incorrect
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A 25-year-old student taking the oral contraceptive pill develops pain and soreness around the genitals. She has just completed an elective year in the United States (USA). On examination, there are multiple, shallow and tender ulcers at the skin and mucous membrane of the vagina.
Which of the following is the most probable diagnosis?
Your Answer: Chancroid
Correct Answer: Genital herpes
Explanation:Sexually Transmitted Diseases: Causes and Symptoms
Sexually transmitted diseases (STDs) are infections that are spread through sexual contact. There are various types of STDs, each with its own set of symptoms and causes. Genital herpes is caused by herpes simplex viruses, with type 2 being responsible for the majority of cases. It can present as vesicular lesions around the genitals, rectum or mouth, but most individuals are asymptomatic. Granuloma inguinale is a chronic bacterial infection that results in nodular lesions that evolve into ulcers. Chancroid is a bacterial STD caused by Haemophilus ducreyi, characterised by painful necrotising genital ulcers. Primary syphilis is caused by the spirochaete Treponema pallidum, with lesions beginning as solitary, raised, firm, red papules that can be several centimetres in diameter. Lymphogranuloma venereum is an uncommon STD caused by Chlamydia trachomatis, characterised by self-limited genital papules or ulcers, followed by painful inguinal and/or femoral lymphadenopathy. Non-infectious causes include fixed drug reactions, Behçet’s disease, neoplasms and trauma. It is important to consider these alternative causes if evaluations for the infectious aetiologies do not lead to a diagnosis. HIV infection should always be considered and tested for.
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This question is part of the following fields:
- Infectious Diseases
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Question 25
Incorrect
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A 27-year-old woman experiences intense vomiting within four hours of consuming lunch at a nearby restaurant. What organism is the most probable cause of this reaction?
Your Answer: Salmonella
Correct Answer: Staphylococcus aureus
Explanation:The diagnosis can be inferred as a result of the short incubation period and intense vomiting.
Gastroenteritis can occur either at home or while traveling, known as travelers’ diarrhea. This condition is characterized by at least three loose to watery stools in 24 hours, accompanied by abdominal cramps, fever, nausea, vomiting, or blood in the stool. The most common cause of travelers’ diarrhea is Escherichia coli. Acute food poisoning is another pattern of illness that results in sudden onset of nausea, vomiting, and diarrhea after ingesting a toxin. Staphylococcus aureus, Bacillus cereus, or Clostridium perfringens are typically responsible for acute food poisoning.
There are several types of infections that can cause gastroenteritis, each with its own typical presentation. Escherichia coli is common among travelers and causes watery stools, abdominal cramps, and nausea. Giardiasis results in prolonged, non-bloody diarrhea, while cholera causes profuse, watery diarrhea and severe dehydration leading to weight loss. Shigella causes bloody diarrhea, vomiting, and abdominal pain, while Staphylococcus aureus results in severe vomiting with a short incubation period. Campylobacter typically starts with a flu-like prodrome and progresses to crampy abdominal pains, fever, and diarrhea, which may be bloody and mimic appendicitis. Bacillus cereus can cause two types of illness, vomiting within six hours, typically due to rice, or diarrheal illness occurring after six hours. Amoebiasis has a gradual onset of bloody diarrhea, abdominal pain, and tenderness that may last for several weeks.
The incubation period for gastroenteritis varies depending on the type of infection. Staphylococcus aureus and Bacillus cereus have an incubation period of 1-6 hours, while Salmonella and Escherichia coli have an incubation period of 12-48 hours. Shigella and Campylobacter have an incubation period of 48-72 hours, while Giardiasis and Amoebiasis have an incubation period of more than seven days.
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This question is part of the following fields:
- Infectious Diseases
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Question 26
Incorrect
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A 30-year-old teacher who recently returned after completing a 3-month assignment in Thailand presented to the Emergency Department with fever, headache, confusion and vomiting in the last two days. She was suspected of having meningitis and underwent a lumbar puncture (LP). The LP findings are as follows:
Normal opening pressure, clear cerebrospinal fluid (CSF).
Investigation Result Normal value
CSF white blood cell count (WBC) 400 cells/µl, 70% lymphocytes < 5 cells/µl
CSF protein 0.5 g/l 0.15–0.4 g/l
CSF glucose 3.8 mmol/l 2.6–4.5 mmol/l
CSF–plasma-glucose ratio 0.72 ≥ 0.66
What is the most likely diagnosis?
Select the SINGLE best answer from the list below.
Select ONE option onlyYour Answer:
Correct Answer: Viral meningitis
Explanation:The cerebrospinal fluid (CSF) findings can help diagnose different types of meningitis. Viral meningitis typically shows clear CSF with a slightly elevated white blood cell count (5-1000 cells/µl, mostly lymphocytes), mildly elevated protein levels, and a normal or slightly low CSF-to-plasma-glucose ratio. Bacterial meningitis, on the other hand, often presents with turbid CSF, a high white blood cell count (>100 cells/µl, mostly neutrophils), elevated protein levels, and a very low CSF-to-plasma-glucose ratio. Fungal meningitis, such as cryptococcal meningitis, usually shows clear or cloudy CSF, a slightly elevated white blood cell count (5-100 cells/µl, mostly lymphocytes), elevated protein levels, and a low CSF-to-plasma-glucose ratio. Tuberculous meningitis typically presents with clear or cloudy CSF, a slightly elevated white blood cell count (5-100 cells/µl, mostly lymphocytes), significantly elevated protein levels, and a very low CSF-to-plasma-glucose ratio. A sub-arachnoid hemorrhage, which is not meningitis, typically presents with a sudden, severe headache and signs of increased intracranial pressure. The CSF in this case often shows xanthochromia.
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This question is part of the following fields:
- Infectious Diseases
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Question 27
Incorrect
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A 25-year-old farm worker is admitted to hospital with a 5-day history of headache, fever, severe myalgia and a petechial rash. He is jaundiced, febrile, has tachycardia and has not passed urine for over 14 hours. His urea level is raised and liver function tests indicate hepatocellular damage.
Which of the following is the most likely diagnosis?
Your Answer:
Correct Answer: Weil’s disease
Explanation:Comparing Zoonotic Infections: Symptoms and Characteristics
Weil’s Disease, Brucellosis, Lyme Disease, Orf, and Rat-bite Fever are all zoonotic infections that can be transmitted from animals to humans. However, each infection has its own unique symptoms and characteristics.
Weil’s Disease is a severe form of leptospirosis caused by Leptospira icterohaemorrhagiae. It is transmitted via direct or indirect contact with animals, especially rodents. Symptoms include flu-like symptoms, severe headache, petechial or purpuric rashes, epistaxis, jaundice, renal failure, meningism, and multiorgan failure.
Brucellosis is caused by the bacterial genus Brucella and is transmitted from animals to humans by ingestion of infected food products, direct contact with an infected animal, or inhalation of aerosols. Symptoms include fever, myalgia, weight loss, coughing, vomiting, lymphadenopathy, and splenomegaly. Males may develop epididymo-orchitis.
Lyme Disease is caused by Borrelia burgdorferi and is transmitted to humans via tick bites from infected ticks. Symptoms include isolated erythema migrans, the characteristic skin rash which has the appearance of a ‘bull’s eye’ and a febrile illness. Untreated patients may go on to develop cardiac, neurological or rheumatological symptoms months after the initial bite.
Orf is a zoonotic mucocutaneous lesion caused by a pox virus and is most commonly seen in workers who handle sheep. Symptoms include firm red papules that develop, enlarge, and become painful before spontaneously resolving. Systemic illness is rare with orf.
Rat-bite Fever is an acute, febrile illness caused by bacteria transmitted by rodents. Symptoms include fever, a rash, and polyarthritis. The rash is usually widespread and may be maculopapular, petechial, or purpuric.
In summary, each zoonotic infection has its own unique symptoms and characteristics, making it important to accurately diagnose and treat each infection accordingly.
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This question is part of the following fields:
- Infectious Diseases
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Question 28
Incorrect
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A 32-year-old woman comes to her General Practitioner complaining of dysuria and lower abdominal pain for the past three days. She has also noticed an unusual vaginal discharge since yesterday. She has been in a committed relationship for the past year and is sexually active. The urine dipstick is normal and her pregnancy test is negative.
What is the most suitable investigation to be performed next, given the most probable diagnosis?
Choose the SINGLE most appropriate investigation from the options below.
Your Answer:
Correct Answer: High vaginal swab for nucleic acid amplification test (NAAT)
Explanation:Investigations for Suspected Sexually Transmitted Infection in Women
When a woman presents with lower abdominal pain, dysuria, and vaginal discharge, it is important to consider the possibility of a sexually transmitted infection (STI), particularly if she is under 25 years old, has had a new sexual partner or multiple partners in the past year, or has a history of STIs. A high vaginal swab for nucleic acid amplification test (NAAT) is the investigation of choice in women suspected of having an STI, such as chlamydia or gonorrhoea. If the NAAT is positive for gonorrhoea, swabs are collected for culture to test for antibiotic susceptibility. Blood tests for inflammatory markers may be useful if an acute abdomen is suspected. HIV serology is not the next investigation in this case, but those diagnosed with STIs are offered screening for HIV. An ultrasound scan of the abdomen and pelvis may be done if a complicated pelvic inflammatory disease is suspected, but it is unlikely to be helpful in this case. Urine culture would not be useful in the absence of urinary symptoms.
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This question is part of the following fields:
- Infectious Diseases
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Question 29
Incorrect
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A 30-year-old homeless woman with drug addiction presents with fever, rash and progressive swelling of the left side of her face, which began with an itchy scab on her left cheek 24 hours ago. Her temperature is 38.5 °C, and she is unable to open her left eye because of the swelling.
Which of the following is the most likely causal organism?Your Answer:
Correct Answer: Group A Streptococcus
Explanation:Bacterial Skin Infections: Understanding the Causes and Symptoms
Erysipelas, a bacterial skin infection, is characterized by a tender, intensely erythematous, indurated plaque with a sharply demarcated border. It is caused by Streptococcus pyogenes, which is often sourced from the host’s nasopharynx. Prodromal symptoms such as malaise, chills, and high fever often precede the onset of skin lesions. Haemophilus influenzae can also cause cellulitis, but the skin lesion described in erysipelas is more consistent with this condition. Herpes simplex viruses cause a wide variety of disease states, including oropharyngeal infections and cold sores. Meningococcaemia, caused by Neisseria meningitidis, presents with a characteristic petechial skin rash on the trunk and legs. Understanding the causes and symptoms of these bacterial skin infections is crucial for proper diagnosis and treatment.
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This question is part of the following fields:
- Infectious Diseases
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Question 30
Incorrect
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As a foundation doctor in the emergency decisions unit, you assess a 28-year-old intravenous drug user who complains of pyrexia and malaise. Upon examination, the patient appears cachectic, pale, and is coughing. A soft murmur is detected, and mild erythematous macular lesions are observed on both palms. Although the patient is experiencing general aches, there is no specific tenderness reported. Can you identify the probable diagnosis and explain the significance of the lesions?
Your Answer:
Correct Answer: Janeway lesions
Explanation:Janeway lesions are painless, red, and bloody lesions that appear on the palms and soles. They are typically associated with infective endocarditis.
Based on the patient’s history of intravenous drug use, fever, and heart murmur, it is likely that he has infective endocarditis. Both janeway lesions (caused by septic emboli) and osler nodes (caused by immune complex deposition) can be present in endocarditis. However, in this case, the lesions are more likely to be janeway lesions as they are not painful.
Roth spots are retinal hemorrhages that can also be seen in endocarditis, but they would be detected during a fundoscopy exam.
If the patient had meningitis, the rash would not be limited to the palms and would not disappear when pressed.
Aetiology of Infective Endocarditis
Infective endocarditis is a condition that affects patients with previously normal valves, rheumatic valve disease, prosthetic valves, congenital heart defects, intravenous drug users, and those who have recently undergone piercings. The strongest risk factor for developing infective endocarditis is a previous episode of the condition. The mitral valve is the most commonly affected valve.
The most common cause of infective endocarditis is Staphylococcus aureus, particularly in acute presentations and intravenous drug users. Historically, Streptococcus viridans was the most common cause, but this is no longer the case except in developing countries. Streptococcus mitis and Streptococcus sanguinis are the two most notable viridans streptococci, commonly found in the mouth and dental plaque. Coagulase-negative Staphylococci such as Staphylococcus epidermidis are the most common cause of endocarditis in patients following prosthetic valve surgery.
Streptococcus bovis is associated with colorectal cancer, with the subtype Streptococcus gallolyticus being most linked to the condition. Non-infective causes of endocarditis include systemic lupus erythematosus and malignancy. Culture negative causes may be due to prior antibiotic therapy or infections caused by Coxiella burnetii, Bartonella, Brucella, or HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella).
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This question is part of the following fields:
- Infectious Diseases
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