In this case, a 70-year-old male who recently underwent aortic valve replacement is presenting with symptoms of fever, fatigue, and overall malaise. Upon examination, splinter hemorrhages are observed on the patient’s fingernails, which raises suspicion of infective endocarditis. Given the patient’s history and symptoms, the most likely causative organism in this particular case is Staphylococcus.

Further Reading:

Infective endocarditis (IE) is an infection that affects the innermost layer of the heart, known as the endocardium. It is most commonly caused by bacteria, although it can also be caused by fungi or viruses. IE can be classified as acute, subacute, or chronic depending on the duration of illness. Risk factors for IE include IV drug use, valvular heart disease, prosthetic valves, structural congenital heart disease, previous episodes of IE, hypertrophic cardiomyopathy, immune suppression, chronic inflammatory conditions, and poor dental hygiene.

The epidemiology of IE has changed in recent years, with Staphylococcus aureus now being the most common causative organism in most industrialized countries. Other common organisms include coagulase-negative staphylococci, streptococci, and enterococci. The distribution of causative organisms varies depending on whether the patient has a native valve, prosthetic valve, or is an IV drug user.

Clinical features of IE include fever, heart murmurs (most commonly aortic regurgitation), non-specific constitutional symptoms, petechiae, splinter hemorrhages, Osler’s nodes, Janeway’s lesions, Roth’s spots, arthritis, splenomegaly, meningism/meningitis, stroke symptoms, and pleuritic pain.

The diagnosis of IE is based on the modified Duke criteria, which require the presence of certain major and minor criteria. Major criteria include positive blood cultures with typical microorganisms and positive echocardiogram findings. Minor criteria include fever, vascular phenomena, immunological phenomena, and microbiological phenomena. Blood culture and echocardiography are key tests for diagnosing IE.

In summary, infective endocarditis is an infection of the innermost layer of the heart that is most commonly caused by bacteria. It can be classified as acute, subacute, or chronic and can be caused by a variety of risk factors. Staphylococcus aureus is now the most common causative organism in most industrialized countries. Clinical features include fever, heart murmurs, and various other symptoms. The diagnosis is based on the modified Duke criteria, which require the presence of certain major and minor criteria. Blood culture and echocardiography are important tests for diagnosing IE.

Aortic stenosis is a common condition where the valve in the heart becomes narrowed due to the progressive calcification that occurs with age. This typically occurs around the age of 70. Other causes of aortic stenosis include calcification of a congenital bicuspid aortic valve and rheumatic fever.

The symptoms of aortic stenosis can vary but commonly include difficulty breathing during physical activity, fainting, dizziness, chest pain (angina), and in severe cases, sudden death. However, it is also possible for aortic stenosis to be asymptomatic, meaning that there are no noticeable symptoms.

When examining a patient with aortic stenosis, there are several signs that may be present. These include a slow-rising and low-volume pulse, a narrow pulse pressure, a sustained apex beat, a thrill (a vibrating sensation) in the area of the aorta, and an ejection click if the valve is pliable. Additionally, there is typically an ejection systolic murmur, which is a specific type of heart murmur, that can be heard loudest in the aortic area (located at the right sternal edge, 2nd intercostal space) and may radiate to the carotid arteries.

It is important to differentiate aortic stenosis from aortic sclerosis, which is a degeneration of the aortic valve but does not cause obstruction of the left ventricular outflow tract. Aortic sclerosis can be distinguished by the presence of a normal pulse character and the absence of radiation of the murmur.

Erythema ab igne is a condition that is frequently observed in older individuals. It typically occurs when they spend extended periods of time near a fire or utilize a hot water bottle in an attempt to relieve pain symptoms. This condition arises due to the harmful effects of heat on the skin, resulting in the appearance of reddened and pigmented areas. Fortunately, erythema ab igne tends to resolve on its own without any specific treatment.

The following provides a summary of common causes for different acid-base disorders.

Respiratory alkalosis can be caused by hyperventilation, such as during periods of anxiety. It can also be a result of conditions like pulmonary embolism, CNS disorders (such as stroke or encephalitis), altitude, pregnancy, or the early stages of aspirin overdose.

Respiratory acidosis, on the other hand, is often associated with chronic obstructive pulmonary disease (COPD), life-threatening asthma, pulmonary edema, sedative drug overdose (such as opiates or benzodiazepines), neuromuscular disease, obesity, or other respiratory conditions.

Metabolic alkalosis can occur due to vomiting, potassium depletion (often caused by diuretic usage), Cushing’s syndrome, or Conn’s syndrome.

Metabolic acidosis with a raised anion gap can be caused by lactic acidosis (such as in cases of hypoxemia, shock, sepsis, or infarction), ketoacidosis (such as in diabetes, starvation, or alcohol excess), renal failure, or poisoning (such as in late stages of aspirin overdose, methanol or ethylene glycol ingestion).

Lastly, metabolic acidosis with a normal anion gap can be a result of conditions like diarrhea, ammonium chloride ingestion, or adrenal insufficiency.

Heat stroke is a condition characterized by a systemic inflammatory response, where the core body temperature exceeds 40.6°C. It is accompanied by changes in mental state and varying levels of organ dysfunction. Heat stroke occurs when the body’s ability to regulate temperature is overwhelmed by a combination of excessive environmental heat, excessive heat production from metabolic processes (usually due to exertion), and inadequate heat loss.

It is important to consider other clinical conditions that can cause an increased core temperature. Sepsis can present similarly and should be ruled out. Neuroleptic malignant syndrome should be excluded in patients taking phenothiazines or other antipsychotics. Serotonin syndrome should be excluded in patients taking serotonergic medications such as SSRIs. Malignant hyperthermia should be considered in patients with a recent history of general anesthesia. Screening for recreational drug use, particularly cocaine, amphetamines, and ecstasy, is also recommended.

In patients with agitation and/or shivering, benzodiazepines (e.g. diazepam) can be beneficial. They help reduce excessive heat production and agitation. In severe cases of agitation, paralysis may be necessary. Dantrolene is commonly used, although there is currently limited high-level evidence supporting its use. Neuroleptics, such as chlorpromazine, which were once commonly used, should be avoided due to potential adverse effects.

Various cooling techniques are recommended, but there is currently insufficient evidence to determine the best approach. Simple measures like cold drinks, fanning, ice water packs, and spraying tepid water can be effective. Cold water immersion therapy may be helpful, but it requires patient stability and cooperation and may not be practical for critically ill patients. Advanced cooling techniques, such as cold IV fluids, surface cooling devices (SCD), intravascular cooling devices (ICD), and extracorporeal circuits, may be used for sicker patients.

Tension pneumothorax is a condition characterized by certain clinical signs. These signs include pulsus paradoxus, which is an abnormal decrease in blood pressure during inspiration; elevated JVP or distended neck veins; diaphoresis or excessive sweating; and cyanosis, which is a bluish discoloration of the skin. Tracheal deviation to the left is often observed in patients with a right-sided pneumothorax. On the affected side, hyper-resonance and absent breath sounds can be expected. Patients with tension pneumothorax typically appear agitated and distressed, and they experience noticeable difficulty in breathing. Hypotension, a pulse rate exceeding 135 bpm, pulsus paradoxus, and elevated JVP are additional signs associated with tension pneumothorax. These signs occur because the expanding pneumothorax compresses the mediastinum, leading to impaired venous return and cardiac output.

Further Reading:

A pneumothorax is an abnormal collection of air in the pleural cavity of the lung. It can be classified by cause as primary spontaneous, secondary spontaneous, or traumatic. Primary spontaneous pneumothorax occurs without any obvious cause in the absence of underlying lung disease, while secondary spontaneous pneumothorax occurs in patients with significant underlying lung diseases. Traumatic pneumothorax is caused by trauma to the lung, often from blunt or penetrating chest wall injuries.

Tension pneumothorax is a life-threatening condition where the collection of air in the pleural cavity expands and compresses normal lung tissue and mediastinal structures. It can be caused by any of the aforementioned types of pneumothorax. Immediate management of tension pneumothorax involves the ABCDE approach, which includes ensuring a patent airway, controlling the C-spine, providing supplemental oxygen, establishing IV access for fluid resuscitation, and assessing and managing other injuries.

Treatment of tension pneumothorax involves needle thoracocentesis as a temporary measure to provide immediate decompression, followed by tube thoracostomy as definitive management. Needle thoracocentesis involves inserting a 14g cannula into the pleural space, typically via the 4th or 5th intercostal space midaxillary line. If the patient is peri-arrest, immediate thoracostomy is advised.

The pathophysiology of tension pneumothorax involves disruption to the visceral or parietal pleura, allowing air to flow into the pleural space. This can occur through an injury to the lung parenchyma and visceral pleura, or through an entry wound to the external chest wall in the case of a sucking pneumothorax. Injured tissue forms a one-way valve, allowing air to enter the pleural space with inhalation but prohibiting air outflow. This leads to a progressive increase in the volume of non-absorbable intrapleural air with each inspiration, causing pleural volume and pressure to rise within the affected hemithorax.

The mortality rate linked to sepsis can vary depending on various factors such as the patient’s age, overall health, and the severity of the infection. However, on average, the mortality rate for sepsis is estimated to be around 30%.

Further Reading:

There are multiple definitions of sepsis, leading to confusion among healthcare professionals. The Sepsis 3 definition describes sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. The Sepsis 2 definition includes infection plus two or more SIRS criteria. The NICE definition states that sepsis is a clinical syndrome triggered by the presence of infection in the blood, activating the body’s immune and coagulation systems. The Sepsis Trust defines sepsis as a dysregulated host response to infection mediated by the immune system, resulting in organ dysfunction, shock, and potentially death.

The confusion surrounding sepsis terminology is further compounded by the different versions of sepsis definitions, known as Sepsis 1, Sepsis 2, and Sepsis 3. The UK organizations RCEM and NICE have not fully adopted the changes introduced in Sepsis 3, causing additional confusion. While Sepsis 3 introduces the use of SOFA scores and abandons SIRS criteria, NICE and the Sepsis Trust have rejected the use of SOFA scores and continue to rely on SIRS criteria. This discrepancy creates challenges for emergency department doctors in both exams and daily clinical practice.

To provide some clarity, RCEM now recommends referring to national standards organizations such as NICE, SIGN, BTS, or others relevant to the area. The Sepsis Trust, in collaboration with RCEM and NICE, has published a toolkit that serves as a definitive reference point for sepsis management based on the sepsis 3 update.

There is a consensus internationally that the terms SIRS and severe sepsis are outdated and should be abandoned. Instead, the terms sepsis and septic shock should be used. NICE defines septic shock as a life-threatening condition characterized by low blood pressure despite adequate fluid replacement and organ dysfunction or failure. Sepsis 3 defines septic shock as persisting hypotension requiring vasopressors to maintain a mean arterial pressure of 65 mmHg or more, along with a serum lactate level greater than 2 mmol/l despite adequate volume resuscitation.

NICE encourages clinicians to adopt an approach of considering sepsis in all patients, rather than relying solely on strict definitions. Early warning or flag systems can help identify patients with possible sepsis.

The BTS guidelines for acute asthma in children recommend administering oral steroids early in the treatment of asthma attacks. It is advised to give a dose of 20 mg prednisolone for children aged 2–5 years and a dose of 30–40 mg for children over 5 years old. If a child is already taking maintenance steroid tablets, they should receive 2 mg/kg prednisolone, up to a maximum dose of 60 mg. If a child vomits after taking the medication, the dose of prednisolone should be repeated. In cases where a child is unable to keep down orally ingested medication, intravenous steroids should be considered. Typically, treatment for up to three days is sufficient, but the duration of the course should be adjusted based on the time needed for recovery. Tapering off the medication is not necessary unless the steroid course exceeds 14 days. For more information, refer to the BTS/SIGN Guideline on the Management of Asthma.

Diabetes Mellitus:
– Definition: a group of metabolic disorders characterized by persistent hyperglycemia caused by deficient insulin secretion, resistance to insulin, or both.
– Types: Type 1 diabetes (absolute insulin deficiency), Type 2 diabetes (insulin resistance and relative insulin deficiency), Gestational diabetes (develops during pregnancy), Other specific types (monogenic diabetes, diabetes secondary to pancreatic or endocrine disorders, diabetes secondary to drug treatment).
– Diagnosis: Type 1 diabetes diagnosed based on clinical grounds in adults presenting with hyperglycemia. Type 2 diabetes diagnosed in patients with persistent hyperglycemia and presence of symptoms or signs of diabetes.
– Risk factors for type 2 diabetes: obesity, inactivity, family history, ethnicity, history of gestational diabetes, certain drugs, polycystic ovary syndrome, metabolic syndrome, low birth weight.

Hypoglycemia:
– Definition: lower than normal blood glucose concentration.
– Diagnosis: defined by Whipple’s triad (signs and symptoms of low blood glucose, low blood plasma glucose concentration, relief of symptoms after correcting low blood glucose).
– Blood glucose level for hypoglycemia: NICE defines it as <3.5 mmol/L, but there is inconsistency across the literature.
– Signs and symptoms: adrenergic or autonomic symptoms (sweating, hunger, tremor), neuroglycopenic symptoms (confusion, coma, convulsions), non-specific symptoms (headache, nausea).
– Treatment options: oral carbohydrate, buccal glucose gel, glucagon, dextrose. Treatment should be followed by re-checking glucose levels.

Treatment of neonatal hypoglycemia:
– Treat with glucose IV infusion 10% given at a rate of 5 mL/kg/hour.
– Initial stat dose of 2 mL/kg over five minutes may be required for severe hypoglycemia.
– Mild asymptomatic persistent hypoglycemia may respond to a single dose of glucagon.
– If hypoglycemia is caused by an oral anti-diabetic drug, the patient should be admitted and ongoing glucose infusion or other therapies may be required.

Note: Patients who have a hypoglycemic episode with a loss of warning symptoms should not drive and should inform the DVLA.

The primary approach to managing nerve gas exposure through medication involves the repeated administration of antidotes. The two antidotes utilized for this purpose are atropine and pralidoxime.

Atropine is the standard anticholinergic medication employed to address the symptoms associated with nerve agent poisoning. It functions as an antagonist for muscarinic acetylcholine receptors, effectively blocking the effects caused by excessive acetylcholine. Initially, a 1.2 mg intravenous bolus of atropine is administered. This dosage is then repeated and doubled every 2-3 minutes until excessive bronchial secretion ceases and miosis (excessive constriction of the pupil) resolves. In some cases, as much as 100 mg of atropine may be necessary.

Pralidoxime (2-PAMCl) is the standard oxime used in the treatment of nerve agent poisoning. Its mechanism of action involves reactivating acetylcholinesterase by scavenging the phosphoryl group attached to the functional hydroxyl group of the enzyme, thereby counteracting the effects of the nerve agent itself. For patients who are moderately or severely poisoned, pralidoxime should be administered intravenously at a dosage of 30 mg/kg of body weight (or 2 g in the case of an adult) over a period of four minutes.