-
Question 1
Incorrect
-
A 67-year-old retired firefighter visits the clinic complaining of recurring burning chest pain. He reports that the pain worsens after consuming take-away food and alcohol, and he experiences increased belching. The patient has a medical history of high cholesterol, type two diabetes, and osteoarthritis. He is currently taking atorvastatin, metformin, gliclazide, naproxen, and omeprazole, which he frequently forgets to take. Which medication is the probable cause of his symptoms?
Your Answer: Atorvastatin
Correct Answer: Naproxen
Explanation:Peptic ulcers can be caused by the use of NSAIDs as a medication. Symptoms of peptic ulcer disease include a burning pain in the chest, which may be accompanied by belching, alcohol consumption, and high-fat foods. However, it is important to rule out any cardiac causes of the pain, especially in patients with a medical history of high cholesterol and type two diabetes.
Other medications that can cause peptic ulcer disease include aspirin and corticosteroids. Each medication has its own specific side effects, such as myalgia with atorvastatin, hypoglycemia with gliclazide, abdominal pain with metformin, and bradycardia with propranolol.
Understanding Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and COX-2 Selective NSAIDs
Non-steroidal anti-inflammatory drugs (NSAIDs) are medications that work by inhibiting the activity of cyclooxygenase enzymes, which are responsible for producing key mediators involved in inflammation such as prostaglandins. By reducing the production of these mediators, NSAIDs can help alleviate pain and reduce inflammation. Examples of NSAIDs include ibuprofen, diclofenac, naproxen, and aspirin.
However, NSAIDs can also have important and common side-effects, such as peptic ulceration and exacerbation of asthma. To address these concerns, COX-2 selective NSAIDs were developed. These medications were designed to reduce the incidence of side-effects seen with traditional NSAIDs, particularly peptic ulceration. Examples of COX-2 selective NSAIDs include celecoxib and etoricoxib.
Despite their potential benefits, COX-2 selective NSAIDs are not widely used due to ongoing concerns about cardiovascular safety. This led to the withdrawal of rofecoxib (‘Vioxx’) in 2004. As with any medication, it is important to discuss the potential risks and benefits of NSAIDs and COX-2 selective NSAIDs with a healthcare provider before use.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 2
Incorrect
-
Which one of the following cellular types or features is not observed in sarcoidosis?
Your Answer: Asteroid bodies
Correct Answer: Reed Sternberg Cells
Explanation:Hodgkin’s disease is characterized by the presence of Reed Sternberg cells, while sarcoid is associated with the presence of all other cell types.
Chronic inflammation can occur as a result of acute inflammation or as a primary process. There are three main processes that can lead to chronic inflammation: persisting infection with certain organisms, prolonged exposure to non-biodegradable substances, and autoimmune conditions involving antibodies formed against host antigens. Acute inflammation involves changes to existing vascular structure and increased permeability of endothelial cells, as well as infiltration of neutrophils. In contrast, chronic inflammation is characterized by angiogenesis and the predominance of macrophages, plasma cells, and lymphocytes. The process may resolve with suppuration, complete resolution, abscess formation, or progression to chronic inflammation. Healing by fibrosis is the main result of chronic inflammation. Granulomas, which consist of a microscopic aggregation of macrophages, are pathognomonic of chronic inflammation and can be found in conditions such as colonic Crohn’s disease. Growth factors released by activated macrophages, such as interferon and fibroblast growth factor, may have systemic features resulting in systemic symptoms and signs in individuals with long-standing chronic inflammation.
-
This question is part of the following fields:
- Haematology And Oncology
-
-
Question 3
Incorrect
-
A 89-year-old diabetic man with known vascular dementia is reporting a loss of sensation on the left side of his body to his caregivers.
During his cranial nerve examination, no abnormalities were found. However, upon neurological examination of his upper and lower limbs, there is a significant sensory loss to light touch, vibration, and pain on the right side. Additionally, he is unable to detect changes in temperature and his joint position sense is impaired on the right side. A CT head scan reveals an infarction in the region of the lateral thalamus on the left side.
Which specific lateral thalamic nucleus has been affected by this stroke?Your Answer: Medial geniculate
Correct Answer: Ventral posterior
Explanation:Injury to the lateral section of the ventral posterior nucleus located in the thalamus can impact the perception of bodily sensations such as touch, pain, proprioception, pressure, and vibration.
The Thalamus: Relay Station for Motor and Sensory Signals
The thalamus is a structure located between the midbrain and cerebral cortex that serves as a relay station for motor and sensory signals. Its main function is to transmit these signals to the cerebral cortex, which is responsible for processing and interpreting them. The thalamus is composed of different nuclei, each with a specific function. The lateral geniculate nucleus relays visual signals, while the medial geniculate nucleus transmits auditory signals. The medial portion of the ventral posterior nucleus (VML) is responsible for facial sensation, while the ventral anterior/lateral nuclei relay motor signals. Finally, the lateral portion of the ventral posterior nucleus is responsible for body sensation, including touch, pain, proprioception, pressure, and vibration. Overall, the thalamus plays a crucial role in the transmission of sensory and motor information to the brain, allowing us to perceive and interact with the world around us.
-
This question is part of the following fields:
- Neurological System
-
-
Question 4
Incorrect
-
A 35-year-old woman, who is 30-weeks pregnant, visits her general practitioner with an itchy vesicular rash. She was recently in contact with a child who had chickenpox and she confesses that she has never had the disease before. The patient is referred to a specialist and prescribed acyclovir. What is the mode of action of this medication?
Your Answer: Pyrophosphate analog which inhibits viral DNA polymerase
Correct Answer: Guanosine analog which inhibits viral DNA polymerase
Explanation:acyclovir is a medication that works by inhibiting viral DNA replication. It is a guanosine analog that lacks a 3 prime hydroxyl group and has a high affinity for viral DNA polymerase. When acyclovir is used during viral DNA replication, the DNA chain terminates, thereby inhibiting viral DNA replication. This medication is commonly used to treat herpes simplex virus infections.
Ribavirin is another guanosine analog that works by inhibiting IMP dehydrogenase. It is often used as part of combination therapy to treat chronic hepatitis C infection.
Interferon-alpha is a human glycoprotein that inhibits the synthesis of mRNA. It is also used to treat chronic hepatitis C infection.
Oseltamivir, also known as Tamiflu, is effective against influenzae A and B. It works by inhibiting neuraminidase, which is a viral enzyme that targets sialic acid on the surface of infected host cells. By inhibiting neuraminidase, oseltamivir prevents virions from being released from the cell.
Foscarnet is a pyrophosphate analog that inhibits viral DNA polymerase. It is used to treat cytomegalovirus retinitis in immunocompromised individuals.
Antiviral agents are drugs used to treat viral infections. They work by targeting specific mechanisms of the virus, such as inhibiting viral DNA polymerase or neuraminidase. Some common antiviral agents include acyclovir, ganciclovir, ribavirin, amantadine, oseltamivir, foscarnet, interferon-α, and cidofovir. Each drug has its own mechanism of action and indications for use, but they all aim to reduce the severity and duration of viral infections.
In addition to these antiviral agents, there are also specific drugs used to treat HIV, a retrovirus. Nucleoside analogue reverse transcriptase inhibitors (NRTI), protease inhibitors (PI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) are all used to target different aspects of the HIV life cycle. NRTIs work by inhibiting the reverse transcriptase enzyme, which is needed for the virus to replicate. PIs inhibit a protease enzyme that is necessary for the virus to mature and become infectious. NNRTIs bind to and inhibit the reverse transcriptase enzyme, preventing the virus from replicating. These drugs are often used in combination to achieve the best possible outcomes for HIV patients.
-
This question is part of the following fields:
- General Principles
-
-
Question 5
Correct
-
A 35-year-old woman arrives at the emergency department complaining of worsening bone pain in her left hip over the past few days. She mentions feeling ill and feverish, but attributes it to a recent cold. The patient is a known IV drug user and has not traveled recently.
During the examination, the left hip appears red and tender, and multiple track marks are visible.
Which organism is most likely responsible for her symptoms?Your Answer: Staphylococcus aureus
Explanation:Osteomyelitis is most commonly caused by Staphylococcus aureus in both adults and children. IV drug use is a known risk factor for this condition as it can introduce microorganisms directly into the bloodstream. While Escherichia coli can also cause osteomyelitis, it is more prevalent in children than adults. Mycobacterium tuberculosis can also lead to osteomyelitis, but it is less common than Staphylococcus aureus. Bone introduction typically occurs via the circulatory system from pulmonary tuberculosis. However, antitubercular therapy has reduced the incidence of tuberculosis, making bone introduction less likely than with Staphylococcus aureus, which is part of the normal skin flora. Salmonella enterica is the most common cause of osteomyelitis in individuals with sickle cell disease. As the patient is not known to have sickle cell, Staphylococcus aureus remains the most probable cause.
Understanding Osteomyelitis: Types, Causes, and Treatment
Osteomyelitis is a bone infection that can be classified into two types: haematogenous and non-haematogenous. Haematogenous osteomyelitis is caused by bacteria in the bloodstream and is usually monomicrobial. It is more common in children and can be caused by risk factors such as sickle cell anaemia, intravenous drug use, immunosuppression, and infective endocarditis. On the other hand, non-haematogenous osteomyelitis is caused by the spread of infection from adjacent soft tissues or direct injury to the bone. It is often polymicrobial and more common in adults, with risk factors such as diabetic foot ulcers, pressure sores, diabetes mellitus, and peripheral arterial disease.
Staphylococcus aureus is the most common cause of osteomyelitis, except in patients with sickle-cell anaemia where Salmonella species are more prevalent. To diagnose osteomyelitis, MRI is the imaging modality of choice, with a sensitivity of 90-100%.
The treatment for osteomyelitis involves a course of antibiotics for six weeks. Flucloxacillin is the preferred antibiotic, but clindamycin can be used for patients who are allergic to penicillin. Understanding the types, causes, and treatment of osteomyelitis is crucial in managing this bone infection.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 6
Correct
-
A 55-year-old man comes to the clinic complaining of black tarry stools. Upon endoscopy, he is found to have a peptic ulcer. What is the primary risk factor for developing peptic ulcers?
Your Answer: Helicobacter pylori colonisation of the stomach
Explanation:Causes of Peptic Ulcers
Peptic ulcers are a common condition that can cause discomfort and pain in the stomach. The most common cause of peptic ulcers is the presence of Helicobacter pylori bacteria in the stomach. This bacteria can cause inflammation and damage to the lining of the stomach, leading to the formation of ulcers. Another common cause of peptic ulcers is the use of nonsteroidal anti-inflammatory drugs (NSAIDs). These drugs can suppress the production of prostaglandins in the stomach, which can lead to inflammation and damage to the stomach lining.
In addition to these causes, smoking can also increase the risk of developing peptic ulcers. Smoking can suppress the production of prostaglandins in the stomach, impair mucosal blood flow, and increase gastric acid secretion. However, it is important to note that being female is not a risk factor for peptic ulcers. In fact, men are more likely to be affected by this condition. Overall, the causes of peptic ulcers can help individuals take steps to prevent and manage this condition.
-
This question is part of the following fields:
- Clinical Sciences
-
-
Question 7
Correct
-
A 50-year old heavy drinker visits his GP complaining of swelling and pain in his left knee. He reports experiencing a similar excruciating pain in his right big toe two years ago, for which he was prescribed allopurinol. What is the patient's diagnosis?
Your Answer: Gout
Explanation:Common Bone and Joint Conditions
Gout is a condition where uric acid builds up in a joint, causing sudden and intense pain, swelling, and redness. It often affects the big toe and can be triggered by alcohol. Men are more likely to develop gout, and it can also affect other joints such as the ankle, knee, and elbow. The presence of uric acid crystals, known as tophi, can confirm the diagnosis. Allopurinol can be used to prevent future attacks.
Osgood-Schlatter disease is caused by tension on the patella tendon, leading to a fracture and symptoms such as pain and swelling over the tibial tubercle.
Osteoporosis is a condition where the bone mineral density is reduced, increasing the risk of fractures, especially in the spine, hip, and wrist. It is most common in women after menopause due to a decrease in estrogen levels.
Osteosarcoma is a type of bone cancer that can be associated with Paget’s disease of bone. It causes pain, especially at night, and increases the risk of fractures.
Rheumatoid arthritis is an autoimmune disorder that commonly affects the small joints in the hands. Inflammatory markers will be elevated, and some cases may have a positive rheumatoid factor.
-
This question is part of the following fields:
- Rheumatology
-
-
Question 8
Correct
-
A 35-year-old teacher presents to her doctor with a complaint of foot pain for the past week. The pain is located on the bottom of her heel and is most severe in the morning and after prolonged periods of sitting at her desk. What is the probable cause of her symptoms?
Your Answer: Plantar fasciitis
Explanation:Understanding Plantar Fasciitis
Plantar fasciitis is a prevalent condition that causes heel pain in adults. The pain is typically more severe around the medial calcaneal tuberosity. To manage this condition, it is essential to rest the feet as much as possible. Wearing shoes with good arch support and cushioned heels can also help alleviate the pain. Additionally, insoles and heel pads may be useful in providing extra support and cushioning to the feet. By taking these steps, individuals with plantar fasciitis can manage their symptoms and improve their overall quality of life.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 9
Correct
-
A 12-year-old girl with a complicated medical history, including asthma and epilepsy, is scheduled for a medication review. Upon reviewing her medical records, you notice that she is currently taking a medication that is contraindicated for her age group. Which of the following medications is contraindicated for this patient?
Your Answer: Doxycycline
Explanation:Doxycycline, a type of tetracycline antibiotic, should not be used in children under 12 years of age.
Understanding Tetracyclines: Antibiotics Used in Clinical Practice
Tetracyclines are a group of antibiotics that are commonly used in clinical practice. They work by inhibiting protein synthesis, specifically by binding to the 30S subunit and blocking the binding of aminoacyl-tRNA. However, bacteria can develop resistance to tetracyclines through increased efflux by plasmid-encoded transport pumps or ribosomal protection.
Tetracyclines are used to treat a variety of conditions such as acne vulgaris, Lyme disease, Chlamydia, and Mycoplasma pneumoniae. However, they should not be given to children under 12 years of age or to pregnant or breastfeeding women due to the risk of discolouration of the infant’s teeth.
While tetracyclines are generally well-tolerated, they can cause adverse effects such as photosensitivity, angioedema, and black hairy tongue. It is important to be aware of these potential side effects and to use tetracyclines only as prescribed by a healthcare professional.
-
This question is part of the following fields:
- General Principles
-
-
Question 10
Incorrect
-
A 55-year-old man with a smoking history of over 30 years presented to the emergency department with acute confusion and disorientation. He was unable to recognize his family members and relatives. He had been experiencing unexplained weight loss, loss of appetite, and occasional episodes of haemoptysis for the past few months. Urgent blood tests were performed, revealing abnormal levels of electrolytes and renal function.
Based on the likely diagnosis, what is the mechanism of action of the hormone that is being secreted excessively in this case?Your Answer: Increased portal blood flow
Correct Answer: Insertion of aquaporin-2 channels
Explanation:Antidiuretic hormone (ADH) plays a crucial role in promoting water reabsorption by inserting aquaporin-2 channels in principal cells. In small-cell lung cancer patients, decreased serum sodium levels are commonly caused by the paraneoplastic syndrome of inadequate ADH secretion (SIADH) or ADH released during the initial lysis of tumour cells after chemotherapy. It is important to note that arteriolar vasodilation, promoting water excretion, decreased urine osmolarity, and increased portal blood flow are not functions of ADH.
Understanding Antidiuretic Hormone (ADH)
Antidiuretic hormone (ADH) is a hormone that is produced in the supraoptic nuclei of the hypothalamus and released by the posterior pituitary gland. Its primary function is to conserve body water by promoting water reabsorption in the collecting ducts of the kidneys through the insertion of aquaporin-2 channels.
ADH secretion is regulated by various factors. An increase in extracellular fluid osmolality, a decrease in volume or pressure, and the presence of angiotensin II can all increase ADH secretion. Conversely, a decrease in extracellular fluid osmolality, an increase in volume, a decrease in temperature, or the absence of ADH can decrease its secretion.
Diabetes insipidus (DI) is a condition that occurs when there is either a deficiency of ADH (cranial DI) or an insensitivity to ADH (nephrogenic DI). Cranial DI can be treated with desmopressin, which is an analog of ADH.
Overall, understanding the role of ADH in regulating water balance in the body is crucial for maintaining proper hydration and preventing conditions like DI.
-
This question is part of the following fields:
- Endocrine System
-
-
Question 11
Incorrect
-
A 6-year-old girl trips and obtains a significant abrasion on her knee. Can you provide the correct sequence of vascular changes that occur in her knee after the injury?
Your Answer: Vasodilation, vasoconstriction, increased permeability of vessels, stasis of red blood cells, neutrophil margination
Correct Answer: Vasoconstriction, vasodilation, increased permeability of vessels, stasis of red blood cells, neutrophil margination
Explanation:Acute inflammation is a response to cell injury in vascularized tissue. It is triggered by chemical factors produced in response to a stimulus, such as fibrin, antibodies, bradykinin, and the complement system. The goal of acute inflammation is to neutralize the offending agent and initiate the repair process. The main characteristics of inflammation are fluid exudation, exudation of plasma proteins, and migration of white blood cells.
The vascular changes that occur during acute inflammation include transient vasoconstriction, vasodilation, increased permeability of vessels, RBC concentration, and neutrophil margination. These changes are followed by leukocyte extravasation, margination, rolling, and adhesion of neutrophils, transmigration across the endothelium, and migration towards chemotactic stimulus.
Leukocyte activation is induced by microbes, products of necrotic cells, antigen-antibody complexes, production of prostaglandins, degranulation and secretion of lysosomal enzymes, cytokine secretion, and modulation of leukocyte adhesion molecules. This leads to phagocytosis and termination of the acute inflammatory response.
-
This question is part of the following fields:
- General Principles
-
-
Question 12
Incorrect
-
A 65-year-old man presents to his GP with worsening breathlessness. He reports difficulty climbing stairs and sleeping, and finds it easier to sleep in his living room chair. He used to manage stairs fine a year ago, but now has to stop twice on the way up.
When asked about other symptoms, he reports feeling slightly wheezy and occasionally coughing up white sputum. He denies any weight loss. His medical history includes angina, non-diabetic hyperglycaemia, and hypertension. He has smoked 15 cigarettes per day since he was 25 and drinks around 5 pints of lager every Friday and Saturday night.
On examination, his oxygen saturations are 96%, respiratory rate 16/min at rest, heart rate 78/min, and blood pressure 141/88 mmHg. Bibasal crackles are heard on auscultation of his lungs.
What is the most likely diagnosis?Your Answer: Chronic obstructive pulmonary disease
Correct Answer: Heart failure
Explanation:Orthopnoea is a distinguishing symptom that can help differentiate between heart failure and COPD in patients. While the symptoms may be non-specific, the presence of orthopnoea, or breathlessness when lying down, is a key indicator of heart failure rather than COPD.
Although the patient has a significant history of smoking, there are no other signs of lung cancer such as weight loss, persistent cough, or coughing up blood. However, it is recommended to conduct an urgent chest X-ray to rule out any serious underlying conditions.
In cases of occupational asthma, symptoms tend to worsen when exposed to triggers in the workplace and improve during time off. However, in this patient’s case, the symptoms have been gradually worsening over time.
Features of Chronic Heart Failure
Chronic heart failure is a condition that affects the heart’s ability to pump blood effectively. It is characterized by several features that can help in its diagnosis. Dyspnoea, or shortness of breath, is a common symptom of chronic heart failure. Patients may also experience coughing, which can be worse at night and accompanied by pink or frothy sputum. Orthopnoea, or difficulty breathing while lying down, and paroxysmal nocturnal dyspnoea, or sudden shortness of breath at night, are also common symptoms.
Another feature of chronic heart failure is the presence of a wheeze, known as a cardiac wheeze. Patients may also experience weight loss, known as cardiac cachexia, which occurs in up to 15% of patients. However, this may be hidden by weight gained due to oedema. On examination, bibasal crackles may be heard, and signs of right-sided heart failure, such as a raised JVP, ankle oedema, and hepatomegaly, may be present.
In summary, chronic heart failure is a condition that can be identified by several features, including dyspnoea, coughing, orthopnoea, paroxysmal nocturnal dyspnoea, wheezing, weight loss, bibasal crackles, and signs of right-sided heart failure. Early recognition and management of these symptoms can help improve outcomes for patients with chronic heart failure.
-
This question is part of the following fields:
- Cardiovascular System
-
-
Question 13
Correct
-
A 40-year-old man visits his GP with his wife who is worried about his behavior. Upon further inquiry, the wife reveals that her husband has been displaying erratic and impulsive behavior for the past 4 months. She also discloses that he inappropriately touched a family friend, which is out of character for him. When asked about his medical history, the patient mentions that he used to be an avid motorcyclist but had a severe accident 6 months ago, resulting in a month-long hospital stay. He denies experiencing flashbacks and reports generally good mood. What is the most probable cause of his symptoms?
Your Answer: Frontal lobe injury
Explanation:Disinhibition can be a result of frontal lobe lesions.
Based on his recent accident, it is probable that the man has suffered from a frontal lobe injury. Such injuries can cause changes in behavior, including impulsiveness and a lack of inhibition.
If the injury were to the occipital lobe, it would likely result in vision loss.
The patient’s denial of flashbacks and positive mood make it unlikely that he has PTSD.
Injuries to the parietal and temporal lobes can lead to communication difficulties and sensory perception problems.
Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.
In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.
-
This question is part of the following fields:
- Neurological System
-
-
Question 14
Incorrect
-
A 42-year-old man arrives at the emergency department with complaints of palpitations and dizziness. He has been experiencing vomiting and diarrhoea for the past week and has also been suffering from muscle weakness and cramps for the last three days. The possibility of hypokalaemia is suspected, and an ECG is ordered. What ECG sign is indicative of hypokalaemia?
Your Answer: Small or absent P waves
Correct Answer: Small or inverted T waves
Explanation:Hypokalaemia, a condition characterized by low levels of potassium in the blood, can be detected through ECG features. These include the presence of U waves, small or absent T waves (which may occasionally be inverted), a prolonged PR interval, ST depression, and a long QT interval. The ECG image provided shows typical U waves and a borderline PR interval. To remember these features, one user suggests the following rhyme: In Hypokalaemia, U have no Pot and no T, but a long PR and a long QT.
-
This question is part of the following fields:
- Cardiovascular System
-
-
Question 15
Incorrect
-
A 26-year-old man is brought to the emergency department after being rescued at sea following a sailing accident. He is currently unresponsive with a Glasgow Coma Score of 9 (E2 V3 M4).
His vital signs include a heart rate of 110 beats per minute, blood pressure of 110/76 mmHg, oxygen saturation of 93%, and temperature of 34.8 ºC. An ECG is unremarkable and venous blood indicates type 2 respiratory failure. The patient's oxygen dissociation curve shows a leftward shift.
What is the cause of the leftward shift in this 26-year-old patient's oxygen dissociation curve?Your Answer: Increased concentration of 2,3-diphosphoglycerate (2,3-DPG)
Correct Answer: Hypothermia
Explanation:The only answer that causes a leftward shift in the oxygen dissociation curve is hypothermia. When tissues undergo aerobic respiration, they generate heat, which changes the shape of the haemoglobin molecule and reduces its affinity for oxygen. This results in the release of oxygen at respiring tissues. In contrast, lower temperatures in the lungs cause a leftward shift in the oxygen dissociation curve, which increases the binding of oxygen to haemoglobin.
Hypercapnia is not the correct answer because it causes a rightward shift in the oxygen dissociation curve. Hypercapnia lowers blood pH, which changes the shape of haemoglobin and reduces its affinity for oxygen.
Hypoxaemia is not the correct answer because the partial pressure of oxygen does not affect the oxygen dissociation curve. The partial pressure of oxygen does not change the affinity of haemoglobin for oxygen.
Increased concentration of 2,3-diphosphoglycerate (2,3-DPG) is not the correct answer because higher concentrations of 2,3-DPG reduce haemoglobin’s affinity for oxygen, causing a right shift in the oxygen dissociation curve.
Understanding the Oxygen Dissociation Curve
The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.
The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.
Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.
-
This question is part of the following fields:
- Respiratory System
-
-
Question 16
Incorrect
-
A 30-year-old female visits her GP complaining of visual disturbance that has been ongoing for 2 days. She reports experiencing blurry vision in her left eye and pain when moving it. She denies having any signs of infection. About 4 months ago, she had a brief episode of weakness and tingling in her left arm that resolved on its own.
What is the probable diagnosis for this patient, and which cells are likely to be targeted by her immune system in this condition?Your Answer: Schwann cells
Correct Answer: Oligodendrocytes
Explanation:The production of myelin in the CNS is the responsibility of oligodendrocytes.
The nervous system is composed of various types of cells, each with their own unique functions. Oligodendroglia cells are responsible for producing myelin in the central nervous system (CNS) and are affected in multiple sclerosis. Schwann cells, on the other hand, produce myelin in the peripheral nervous system (PNS) and are affected in Guillain-Barre syndrome. Astrocytes provide physical support, remove excess potassium ions, help form the blood-brain barrier, and aid in physical repair. Microglia are specialised CNS phagocytes, while ependymal cells provide the inner lining of the ventricles.
In summary, the nervous system is made up of different types of cells, each with their own specific roles. Oligodendroglia and Schwann cells produce myelin in the CNS and PNS, respectively, and are affected in certain diseases. Astrocytes provide physical support and aid in repair, while microglia are specialised phagocytes in the CNS. Ependymal cells line the ventricles. Understanding the functions of these cells is crucial in understanding the complex workings of the nervous system.
-
This question is part of the following fields:
- Neurological System
-
-
Question 17
Incorrect
-
A 72-year-old man visits his physician after being diagnosed with osteoporosis due to a hip fracture. The doctor suggests prescribing alendronic acid, a bisphosphonate, to prevent future fractures.
What is the mechanism of action of alendronic acid?Your Answer: Osteoclast stimulation
Correct Answer: Osteoclast inhibition
Explanation:Bisphosphonates work by inhibiting osteoclasts, which are responsible for breaking down bone. This promotes bone health and is commonly used in the treatment of osteoporosis. Bisphosphonates do not cause increased cholecalciferol synthesis or osteoblast inhibition, but are actually used in the management of hypercalcemia. Osteoclast stimulation would be harmful to patients and is not the correct description of the action of bisphosphonates.
Bisphosphonates: Uses, Adverse Effects, and Patient Counselling
Bisphosphonates are drugs that mimic the action of pyrophosphate, a molecule that helps prevent bone demineralization. They work by inhibiting osteoclasts, the cells responsible for breaking down bone tissue. Bisphosphonates are commonly used to prevent and treat osteoporosis, hypercalcemia, Paget’s disease, and pain from bone metastases.
However, bisphosphonates can cause adverse effects such as oesophageal reactions, osteonecrosis of the jaw, and an increased risk of atypical stress fractures of the proximal femoral shaft in patients taking alendronate. Patients may also experience an acute phase response, which includes fever, myalgia, and arthralgia following administration. Hypocalcemia may also occur due to reduced calcium efflux from bone, but this is usually clinically unimportant.
To minimize the risk of adverse effects, patients taking oral bisphosphonates should swallow the tablets whole with plenty of water while sitting or standing. They should take the medication on an empty stomach at least 30 minutes before breakfast or another oral medication and remain upright for at least 30 minutes after taking the tablet. Hypocalcemia and vitamin D deficiency should be corrected before starting bisphosphonate treatment. However, calcium supplements should only be prescribed if dietary intake is inadequate when starting bisphosphonate treatment for osteoporosis. Vitamin D supplements are usually given.
The duration of bisphosphonate treatment varies depending on the level of risk. Some experts recommend stopping bisphosphonates after five years if the patient is under 75 years old, has a femoral neck T-score of more than -2.5, and is at low risk according to FRAX/NOGG.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 18
Incorrect
-
A 31-year-old woman visits her doctor with her 3-month-old son for a routine check-up. During the visit, the woman expresses her concern about her inability to breastfeed her baby, despite several attempts.
The woman has a medical history of sensorineural deafness, which she acquired after contracting bacterial meningitis as a child.
Her serum prolactin levels are within the normal range at 250 g/L (34-386 ng/mL). The doctor explains that the milk let-down reflex also requires the hormone oxytocin.
Can you identify the part of the brain where oxytocin is synthesized?Your Answer: Pineal gland
Correct Answer: Paraventricular nucleus
Explanation:The paraventricular nucleus of the hypothalamus is responsible for producing oxytocin. This hormone is synthesized in the periventricular nucleus and then secreted into the posterior pituitary gland, where it is stored and eventually released into the systemic circulation. Oxytocin plays a crucial role in the milk let-down reflex, causing the myoepithelial cells of the breast to contract and release milk. However, this patient may have difficulty breastfeeding due to complications from her childhood meningitis. It is important to note that oxytocin is not synthesized or released from the arcuate nucleus, Edinger-Westphal nucleus, or pineal gland.
The hypothalamus is a part of the brain that plays a crucial role in maintaining the body’s internal balance, or homeostasis. It is located in the diencephalon and is responsible for regulating various bodily functions. The hypothalamus is composed of several nuclei, each with its own specific function. The anterior nucleus, for example, is involved in cooling the body by stimulating the parasympathetic nervous system. The lateral nucleus, on the other hand, is responsible for stimulating appetite, while lesions in this area can lead to anorexia. The posterior nucleus is involved in heating the body and stimulating the sympathetic nervous system, and damage to this area can result in poikilothermia. Other nuclei include the septal nucleus, which regulates sexual desire, the suprachiasmatic nucleus, which regulates circadian rhythm, and the ventromedial nucleus, which is responsible for satiety. Lesions in the paraventricular nucleus can lead to diabetes insipidus, while lesions in the dorsomedial nucleus can result in savage behavior.
-
This question is part of the following fields:
- Neurological System
-
-
Question 19
Correct
-
A 12-year-old male patient has been diagnosed with Friedreich's ataxia, an autosomal recessive genetic disease that causes difficulty walking, a loss of sensation in the arms and legs and impaired speech that worsens over time. What condition should this patient be screened for as a result of having this disease?
Your Answer: Hypertrophic obstructive cardiomyopathy
Explanation:Friedreich’s ataxia is a genetic disorder caused by a deficiency of the frataxin protein, which can lead to cardiac neuropathy and hypertrophic obstructive cardiomyopathy. This condition is not associated with haemophilia, coarctation of the aorta, streptococcal pharyngitis, Kawasaki disease, or coronary artery aneurysm. However, Group A streptococcal infections can cause acute rheumatic fever and chronic rheumatic heart disease, which are autoimmune diseases that affect the heart.
Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder that affects muscle tissue and is inherited in an autosomal dominant manner. It is caused by mutations in genes that encode contractile proteins, with the most common defects involving the β-myosin heavy chain protein or myosin-binding protein C. HOCM is characterized by left ventricle hypertrophy, which leads to decreased compliance and cardiac output, resulting in predominantly diastolic dysfunction. Biopsy findings show myofibrillar hypertrophy with disorganized myocytes and fibrosis. HOCM is often asymptomatic, but exertional dyspnea, angina, syncope, and sudden death can occur. Jerky pulse, systolic murmurs, and double apex beat are also common features. HOCM is associated with Friedreich’s ataxia and Wolff-Parkinson White. ECG findings include left ventricular hypertrophy, non-specific ST segment and T-wave abnormalities, and deep Q waves. Atrial fibrillation may occasionally be seen.
-
This question is part of the following fields:
- Cardiovascular System
-
-
Question 20
Incorrect
-
A 28-year-old male comes to the Emergency Department complaining of a severely painful, reddened right-eye that has been going on for 6 hours. He also reports experiencing haloes around light and reduced visual acuity. The patient has a history of hypermetropia. Upon examination, the right-eye appears red with a fixed and dilated pupil and conjunctival injection.
What is the most probable diagnosis?Your Answer: Vitreous haemorrhage
Correct Answer: Acute closed-angle glaucoma
Explanation:The correct diagnosis is acute closed-angle glaucoma, which is characterized by an increase in intra-ocular pressure due to impaired aqueous outflow. Symptoms include a painful red eye, reduced visual acuity, and haloes around light. Risk factors include hypermetropia, pupillary dilatation, and age-related lens growth. Examination findings typically include a fixed dilated pupil with conjunctival injection. Treatment options include reducing aqueous secretions with acetazolamide and increasing pupillary constriction with topical pilocarpine.
Anterior uveitis is an incorrect diagnosis, as it refers to inflammation of the anterior portion of the uvea and is associated with systemic inflammatory conditions. Ophthalmoscopy findings include an irregular pupil.
Central retinal vein occlusion is also an incorrect diagnosis, as it causes acute blindness due to thromboembolism or vasculitis in the central retinal vein. Ophthalmoscopy typically reveals severe retinal haemorrhages.
Infective conjunctivitis is another incorrect diagnosis, as it is characterized by sore, red eyes with discharge. Bacterial causes typically result in purulent discharge, while viral cases often have serous discharge.
Acute angle closure glaucoma (AACG) is a type of glaucoma where there is a rise in intraocular pressure (IOP) due to a blockage in the outflow of aqueous humor. This condition is more likely to occur in individuals with hypermetropia, pupillary dilation, and lens growth associated with aging. Symptoms of AACG include severe pain, decreased visual acuity, a hard and red eye, haloes around lights, and a semi-dilated non-reacting pupil. AACG is an emergency and requires urgent referral to an ophthalmologist. The initial medical treatment involves a combination of eye drops, such as a direct parasympathomimetic, a beta-blocker, and an alpha-2 agonist, as well as intravenous acetazolamide to reduce aqueous secretions. Definitive management involves laser peripheral iridotomy, which creates a tiny hole in the peripheral iris to allow aqueous humor to flow to the angle.
-
This question is part of the following fields:
- Neurological System
-
-
Question 21
Correct
-
As a physician, assessing a 23-year-old male who arrived at the emergency department with a triceps muscle injury causing left elbow extension loss. Can you identify the origin of the long head of this muscle?
Your Answer: Infraglenoid tubercle of the scapula
Explanation:The triceps muscle, which gets its name from the Latin word for three-headed, is responsible for extending the elbow. It is made up of three heads: the long head, which originates from the infraglenoid tubercle of the scapula; the lateral head, which comes from the dorsal surface of the humerus; and the medial head, which originates from the posterior surface of the humerus. These three sets of fibers come together to form a single tendon that inserts onto the olecranon process of the ulna.
Anatomy of the Triceps Muscle
The triceps muscle is a large muscle located on the back of the upper arm. It is composed of three heads: the long head, lateral head, and medial head. The long head originates from the infraglenoid tubercle of the scapula, while the lateral head originates from the dorsal surface of the humerus, lateral and proximal to the groove of the radial nerve. The medial head originates from the posterior surface of the humerus on the inferomedial side of the radial groove and both of the intermuscular septae.
All three heads of the triceps muscle insert into the olecranon process of the ulna, with some fibers inserting into the deep fascia of the forearm and the posterior capsule of the elbow. The triceps muscle is innervated by the radial nerve and supplied with blood by the profunda brachii artery.
The primary action of the triceps muscle is elbow extension. The long head can also adduct the humerus and extend it from a flexed position. The radial nerve and profunda brachii vessels lie between the lateral and medial heads of the triceps muscle. Understanding the anatomy of the triceps muscle is important for proper diagnosis and treatment of injuries or conditions affecting this muscle.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 22
Correct
-
Surgery can trigger a significant stress response in individuals, leading to the release of high levels of adrenaline from the adrenal glands. This adrenaline has the potential to activate various adrenergic receptors, including the α1 receptor. What happens when this receptor is activated?
Your Answer: Systemic vasoconstriction
Explanation:Adrenergic receptors are a type of G protein-coupled receptors that respond to the catecholamines epinephrine and norepinephrine. These receptors are primarily involved in the sympathetic nervous system. There are four types of adrenergic receptors: α1, α2, β1, and β2. Each receptor has a different potency order and primary action. The α1 receptor responds equally to norepinephrine and epinephrine, causing smooth muscle contraction. The α2 receptor has mixed effects and responds equally to both catecholamines. The β1 receptor responds equally to epinephrine and norepinephrine, causing cardiac muscle contraction. The β2 receptor responds much more strongly to epinephrine than norepinephrine, causing smooth muscle relaxation.
-
This question is part of the following fields:
- General Principles
-
-
Question 23
Incorrect
-
Which of the following is not secreted by the islets of Langerhans?
Your Answer: Glucagon
Correct Answer: Secretin
Explanation:Mucosal cells in the duodenum and jejunum release secretin.
Hormones Released from the Islets of Langerhans
The islets of Langerhans in the pancreas are responsible for the production and secretion of several hormones that play a crucial role in regulating blood glucose levels. The beta cells in the islets of Langerhans are responsible for producing insulin, which accounts for 70% of the total secretions. Insulin helps to lower blood glucose levels by promoting the uptake of glucose by cells and tissues throughout the body.
The alpha cells in the islets of Langerhans produce glucagon, which has the opposite effect of insulin. Glucagon raises blood glucose levels by stimulating the liver to release stored glucose into the bloodstream. The delta cells in the islets of Langerhans produce somatostatin, which helps to regulate the release of insulin and glucagon.
Finally, the F cells in the islets of Langerhans produce pancreatic polypeptide, which plays a role in regulating pancreatic exocrine function and appetite. Together, these hormones work to maintain a delicate balance of blood glucose levels in the body.
-
This question is part of the following fields:
- Endocrine System
-
-
Question 24
Correct
-
A 47-year-old woman is being evaluated on the ward 24 hours after a thyroidectomy. Although she has been feeling fine, she has noticed a hoarseness in her voice. Which nerve may have been affected during the operation?
Your Answer: Right recurrent laryngeal nerve
Explanation:During neck surgery, the right recurrent laryngeal nerve is at a higher risk of injury compared to the left due to its diagonal path across the neck originating under the subclavian. Both the recurrent and superior laryngeal nerves play a crucial role in the sensory and motor function of the vocal cords. The superior laryngeal nerve is less likely to be damaged during thyroid surgery in the lower neck as it descends from above the vocal cords. The glossopharyngeal nerve is also not commonly affected by this mechanism, but if injured, it can cause difficulty swallowing, changes in taste, and altered sensation in the back of the mouth. Hypoglossal nerve injury is rare and does not align with this mechanism, but if it occurs, it can lead to atrophy of the tongue muscles on the same side.
The Recurrent Laryngeal Nerve: Anatomy and Function
The recurrent laryngeal nerve is a branch of the vagus nerve that plays a crucial role in the innervation of the larynx. It has a complex path that differs slightly between the left and right sides of the body. On the right side, it arises anterior to the subclavian artery and ascends obliquely next to the trachea, behind the common carotid artery. It may be located either anterior or posterior to the inferior thyroid artery. On the left side, it arises left to the arch of the aorta, winds below the aorta, and ascends along the side of the trachea.
Both branches pass in a groove between the trachea and oesophagus before entering the larynx behind the articulation between the thyroid cartilage and cricoid. Once inside the larynx, the recurrent laryngeal nerve is distributed to the intrinsic larynx muscles (excluding cricothyroid). It also branches to the cardiac plexus and the mucous membrane and muscular coat of the oesophagus and trachea.
Damage to the recurrent laryngeal nerve, such as during thyroid surgery, can result in hoarseness. Therefore, understanding the anatomy and function of this nerve is crucial for medical professionals who perform procedures in the neck and throat area.
-
This question is part of the following fields:
- Neurological System
-
-
Question 25
Incorrect
-
You are assessing a patient who is one day post-appendectomy. The procedure was done laparoscopically and was uncomplicated with an estimated blood loss of 150ml. The patient reports feeling comfortable, but when asked, she mentions that she has not had a bowel movement or passed gas and is experiencing mild bloating.
What could be the probable reason for these symptoms?Your Answer: Hernia
Correct Answer: Ileus
Explanation:postoperative ileus is a common complication that can occur after gastrointestinal surgery. This condition is characterized by a slowdown or complete stoppage of intestinal movement following surgery, and is often referred to as a ‘functional bowel obstruction’ or ‘paralytic’ ileus. Patients may report not passing stool or gas, and bowel sounds may be absent on auscultation. Unlike mechanical bowel obstruction, which is associated with a tinkling sound, postoperative ileus can cause bowel distension and third-space volume loss, leading to dehydration and electrolyte imbalances. Diagnosis can be confirmed through imaging, such as an abdominal x-ray, which typically shows generalised dilatation of bowel loops with no transition point and visible air in the rectum.
Postoperative ileus, also known as paralytic ileus, is a common complication that can occur after bowel surgery, particularly if the bowel has been extensively handled. This condition is characterized by reduced bowel peristalsis, which can lead to pseudo-obstruction. Symptoms of postoperative ileus include abdominal distention, bloating, pain, nausea, vomiting, inability to pass flatus, and difficulty tolerating an oral diet. It is important to check for deranged electrolytes, such as potassium, magnesium, and phosphate, as they can contribute to the development of postoperative ileus.
The management of postoperative ileus typically involves nil-by-mouth initially, which may progress to small sips of clear fluids. If vomiting occurs, a nasogastric tube may be necessary. Intravenous fluids are administered to maintain normovolaemia, and additives may be used to correct any electrolyte disturbances. In severe or prolonged cases, total parenteral nutrition may be required. Overall, postoperative ileus is a common complication that requires careful management to ensure a successful recovery.
-
This question is part of the following fields:
- General Principles
-
-
Question 26
Correct
-
A mother brought her 5-year-old daughter to a refugee camp clinic due to leg bowing. Over the past few months, the mother has noticed her daughter's legs appear curved, causing a slightly waddling gait. The daughter does not complain of soreness in the legs and has a good range of movement. There are no rashes or bruises noted. The patient has no relevant medical history, although the mother mentions difficulty adjusting to the UK lifestyle and weather since leaving Afghanistan.
Which blood test would be most helpful to request?Your Answer: Vitamin D level
Explanation:Rickets is caused by a deficiency in Vitamin D.
The stem correctly identifies Vitamin D as the cause of rickets, which is characterized by bowed legs and a waddling gait. The patient’s reduced calcium absorption is likely due to a change in sunlight exposure, as sunlight is a source of Vitamin D. This deficiency leads to decreased bone mineral density.
Autoantibody screen, coagulation screen, and full blood count are all incorrect as they are not specific to the symptoms described in the question. Vitamin B12 deficiency is also incorrect as it causes peripheral neuropathy, which the patient does not exhibit.
Understanding Vitamin D
Vitamin D is a type of vitamin that is soluble in fat and is essential for the metabolism of calcium and phosphate in the body. It is converted into calcifediol in the liver and then into calcitriol, which is the active form of vitamin D, in the kidneys. Vitamin D can be obtained from two sources: vitamin D2, which is found in plants, and vitamin D3, which is present in dairy products and can also be synthesized by the skin when exposed to sunlight.
The primary function of vitamin D is to increase the levels of calcium and phosphate in the blood. It achieves this by increasing the absorption of calcium in the gut and the reabsorption of calcium in the kidneys. Vitamin D also stimulates osteoclastic activity, which is essential for bone growth and remodeling. Additionally, it increases the reabsorption of phosphate in the kidneys.
A deficiency in vitamin D can lead to two conditions: rickets in children and osteomalacia in adults. Rickets is characterized by soft and weak bones, while osteomalacia is a condition where the bones become weak and brittle. Therefore, it is crucial to ensure that the body receives an adequate amount of vitamin D to maintain healthy bones and overall health.
-
This question is part of the following fields:
- General Principles
-
-
Question 27
Correct
-
A 3-year-old child presents to their pediatrician with severe perianal itching that is particularly worse at night. The child has no known medical conditions and has been healthy up until this point. The birth history was unremarkable, and the child is up to date with their vaccinations. There have been no developmental concerns.
After taking a thorough history, including asking about symptoms in other family members, the pediatrician uses the 'tape test' to make a diagnosis and prescribes appropriate treatment.
What is the most probable cause of the child's pruritus in this scenario?Your Answer: Enterobius vermicularis infection
Explanation:The most likely diagnosis for a 2-year-old child with perianal itching, especially at night, is Enterobius vermicularis infection, commonly known as pinworms. This is a common condition in young children and can cause discomfort and restlessness due to the itching around the anus.
The diagnosis can be confirmed through the tape test, where adhesive tape is applied around the anus of the child upon waking and then examined under a microscope for the presence of worms or their eggs. While haemorrhoids can also cause peri-anal itching, they are not the most probable diagnosis in this case, especially given the age of the child.
Echinococcus granulosus infection, which causes hydatid disease and cysts, is not a likely diagnosis for perianal itching. Perianal eczema is another possibility, but it would typically present with visible signs upon inspection, and the tape test would not be used for diagnosis.
Helminths are a group of parasitic worms that can infect humans and cause various diseases. Nematodes, also known as roundworms, are one type of helminth. Strongyloides stercoralis is a type of roundworm that enters the body through the skin and can cause symptoms such as diarrhea, abdominal pain, and skin lesions. Treatment for this infection typically involves the use of ivermectin or benzimidazoles. Enterobius vermicularis, also known as pinworm, is another type of roundworm that can cause perianal itching and other symptoms. Diagnosis is made by examining sticky tape applied to the perianal area. Treatment typically involves benzimidazoles.
Hookworms, such as Ancylostoma duodenale and Necator americanus, are another type of roundworm that can cause gastrointestinal infections and anemia. Treatment typically involves benzimidazoles. Loa loa is a type of roundworm that is transmitted by deer fly and mango fly and can cause red, itchy swellings called Calabar swellings. Treatment involves the use of diethylcarbamazine. Trichinella spiralis is a type of roundworm that can develop after eating raw pork and can cause fever, periorbital edema, and myositis. Treatment typically involves benzimidazoles.
Onchocerca volvulus is a type of roundworm that causes river blindness and is spread by female blackflies. Treatment involves the use of ivermectin. Wuchereria bancrofti is another type of roundworm that is transmitted by female mosquitoes and can cause blockage of lymphatics and elephantiasis. Treatment involves the use of diethylcarbamazine. Toxocara canis, also known as dog roundworm, is transmitted through ingestion of infective eggs and can cause visceral larva migrans and retinal granulomas. Treatment involves the use of diethylcarbamazine. Ascaris lumbricoides, also known as giant roundworm, can cause intestinal obstruction and occasionally migrate to the lung. Treatment typically involves benzimidazoles.
Cestodes, also known as tapeworms, are another type of helminth. Echinococcus granulosus is a tapeworm that is transmitted through ingestion of eggs in dog feces and can cause liver cysts and anaphylaxis if the cyst ruptures
-
This question is part of the following fields:
- General Principles
-
-
Question 28
Incorrect
-
A middle-aged woman presents with complaints of profound sadness, marked difficulty concentrating, and an inability to make decisions. During the evaluation, she speaks slowly and struggles to articulate her emotions. How would you characterize the alterations in her cognitive functioning and thought processes?
Your Answer: Thought block
Correct Answer: Psychomotor retardation
Explanation:Psychomotor Retardation in Severe Depression
Psychomotor retardation is a cognitive symptom commonly observed in individuals with severe depression. It is characterized by a significant slowing down of both thinking and behavior. This symptom can manifest in various ways, such as slowed speech, reduced movement, and delayed responses. Psychomotor retardation can significantly impact an individual’s ability to carry out daily activities and can lead to social withdrawal and isolation.
It is essential to differentiate psychomotor retardation from other forms of thought disorders seen in other psychiatric conditions such as mania and schizophrenia. In mania, individuals may experience racing thoughts and increased energy levels, while in schizophrenia, disorganized thinking and speech patterns are common. Therefore, a thorough evaluation by a mental health professional is necessary to accurately diagnose and treat psychomotor retardation in severe depression.
-
This question is part of the following fields:
- Psychiatry
-
-
Question 29
Correct
-
A 47-year-old woman presents with persistent diarrhoea and flushing and is diagnosed with medullary carcinoma of the thyroid via a fine needle aspiration of her thyroid gland. She has been referred to the endocrine clinic for further management. You are a medical student shadowing the attending physician and ask where calcitonin is released from.
What is the physician's likely response?Your Answer: Parafollicular cells of the thyroid
Explanation:The parafollicular cells of the thyroid release calcitonin, which is a hormone that helps to reduce calcium and phosphate levels by inhibiting osteoclasts. Medullary thyroid cancer originates from these cells and results in the overproduction of calcitonin. Calcitonin is typically released in response to hypercalcaemia and promotes the excretion of metabolites such as sodium and potassium. Follicular dendritic cells and follicular B cells are types of immune cells found in lymphoid tissue, while follicular cells in the thyroid gland produce and secrete thyroid hormones. Delta cells are another type of cell found in the pancreas that produce somatostatin.
Understanding Calcitonin and Its Role in Regulating Calcium Levels
Calcitonin is a hormone that is produced by the parafollicular cells or C cells of the thyroid gland. It is released in response to high levels of calcium in the blood, which can occur due to various factors such as bone resorption, vitamin D toxicity, or certain cancers. The main function of calcitonin is to decrease the levels of calcium and phosphate in the blood by inhibiting the activity of osteoclasts, which are cells that break down bone tissue and release calcium into the bloodstream.
Calcitonin works by binding to specific receptors on the surface of osteoclasts, which reduces their ability to resorb bone. This leads to a decrease in the release of calcium and phosphate into the bloodstream, which helps to restore normal levels of these minerals. In addition to its effects on bone metabolism, calcitonin also has other physiological functions such as regulating kidney function and modulating the immune system.
Overall, calcitonin plays an important role in maintaining calcium homeostasis in the body and preventing the development of conditions such as hypercalcemia, which can have serious health consequences. By inhibiting osteoclast activity and promoting bone formation, calcitonin helps to maintain the structural integrity of bones and prevent fractures. Understanding the mechanisms of calcitonin action can provide insights into the pathophysiology of bone diseases and inform the development of new treatments for these conditions.
-
This question is part of the following fields:
- General Principles
-
-
Question 30
Incorrect
-
Which of the following would be a common hypersensitivity response that results in tissue damage due to the accumulation of immune complexes?
Your Answer: Goodpasture syndrome
Correct Answer: Post-streptococcus glomerulonephritis
Explanation:Type 3 reactions involve immune complexes and can result in post-streptococcus glomerulonephritis. An example of a type 1 IgE-mediated anaphylactic reaction is tongue and lip swelling shortly after consuming shellfish. Goodpasture syndrome is an instance of a type 2 reaction that is mediated by IgG and IgM antibodies. Type 4 (delayed) reactions are caused by T lymphocytes and can lead to contact dermatitis and a positive Mantoux test. Contact dermatitis is frequently caused by nickel, which is commonly found in inexpensive jewelry like Christmas cracker rings.
Classification of Hypersensitivity Reactions
Hypersensitivity reactions are classified into four types according to the Gell and Coombs classification. Type I, also known as anaphylactic hypersensitivity, occurs when an antigen reacts with IgE bound to mast cells. This type of reaction is commonly seen in atopic conditions such as asthma, eczema, and hay fever. Type II hypersensitivity occurs when cell-bound IgG or IgM binds to an antigen on the cell surface, leading to autoimmune conditions such as autoimmune hemolytic anemia, ITP, and Goodpasture’s syndrome. Type III hypersensitivity occurs when free antigen and antibody (IgG, IgA) combine to form immune complexes, leading to conditions such as serum sickness, systemic lupus erythematosus, and post-streptococcal glomerulonephritis. Type IV hypersensitivity is T-cell mediated and includes conditions such as tuberculosis, graft versus host disease, and allergic contact dermatitis.
In recent times, a fifth category has been added to the classification of hypersensitivity reactions. Type V hypersensitivity occurs when antibodies recognize and bind to cell surface receptors, either stimulating them or blocking ligand binding. This type of reaction is seen in conditions such as Graves’ disease and myasthenia gravis. Understanding the classification of hypersensitivity reactions is important in the diagnosis and management of these conditions.
-
This question is part of the following fields:
- General Principles
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)