Addison’s disease, also known as adrenal insufficiency, is characterized by a gradual onset of symptoms over several weeks, although it can sometimes occur suddenly. The diagnosis of Addison’s disease can be challenging as its symptoms, such as fatigue, muscle pain, weight loss, and nausea, are non-specific. However, a key feature is low blood pressure. The disease is associated with changes in pigmentation, ranging from increased pigmentation due to elevated ACTH levels to the development of vitiligo caused by the autoimmune destruction of melanocytes.

Patients with Addison’s disease often exhibit hyponatremia (low sodium levels) and hyperkalemia (high potassium levels). If the patient is dehydrated, this may be reflected in elevated urea and creatinine levels. While hypercalcemia (high calcium levels) and hypoglycemia (low blood sugar levels) can occur in Addison’s disease, they are less common than hyponatremia and hyperkalemia.

In contrast, diabetes insipidus, characterized by normal or elevated sodium levels, does not cause pigmentation changes. Cushing’s syndrome, which results from excess steroid production, is almost the opposite of Addison’s disease, with hypertension (high blood pressure) and hypokalemia (low potassium levels) being typical symptoms. Phaeochromocytoma, on the other hand, is associated with episodes of high blood pressure and hyperglycemia (high blood sugar levels).

Further Reading:

Addison’s disease, also known as primary adrenal insufficiency or hypoadrenalism, is a rare disorder caused by the destruction of the adrenal cortex. This leads to reduced production of glucocorticoids, mineralocorticoids, and adrenal androgens. The deficiency of cortisol results in increased production of adrenocorticotropic hormone (ACTH) due to reduced negative feedback to the pituitary gland. This condition can cause metabolic disturbances such as hyperkalemia, hyponatremia, hypercalcemia, and hypoglycemia.

The symptoms of Addison’s disease can vary but commonly include fatigue, weight loss, muscle weakness, and low blood pressure. It is more common in women and typically affects individuals between the ages of 30-50. The most common cause of primary hypoadrenalism in developed countries is autoimmune destruction of the adrenal glands. Other causes include tuberculosis, adrenal metastases, meningococcal septicaemia, HIV, and genetic disorders.

The diagnosis of Addison’s disease is often suspected based on low cortisol levels and electrolyte abnormalities. The adrenocorticotropic hormone stimulation test is commonly used for confirmation. Other investigations may include adrenal autoantibodies, imaging scans, and genetic screening.

Addisonian crisis is a potentially life-threatening condition that occurs when there is an acute deficiency of cortisol and aldosterone. It can be the first presentation of undiagnosed Addison’s disease. Precipitating factors of an Addisonian crisis include infection, dehydration, surgery, trauma, physiological stress, pregnancy, hypoglycemia, and acute withdrawal of long-term steroids. Symptoms of an Addisonian crisis include malaise, fatigue, nausea or vomiting, abdominal pain, fever, muscle pains, dehydration, confusion, and loss of consciousness.

There is no fixed consensus on diagnostic criteria for an Addisonian crisis, as symptoms are non-specific. Investigations may include blood tests, blood gas analysis, and septic screens if infection is suspected. Management involves administering hydrocortisone and fluids. Hydrocortisone is given parenterally, and the dosage varies depending on the age of the patient. Fluid resuscitation with saline is necessary to correct any electrolyte disturbances and maintain blood pressure. The underlying cause of the crisis should also be identified and treated. Close monitoring of sodium levels is important to prevent complications such as osmotic demyelination syndrome.

In patients with hypothermia, the pulse check during CPR should be extended to 1 minute. Additionally, several adjustments need to be made to the CPR protocol. Firstly, mechanical ventilation should be used due to the stiffness of the chest wall. Secondly, the dosing or omission of cardiac arrest drugs should be adjusted based on the patient’s temperature. The defibrillation pattern should also be modified, with 3 shocks attempted before re-attempting defibrillation only when the body temperature is above 30ºC. Certain electrolyte disturbances, such as mild hypokalemia, should not be treated as potassium levels typically rise with Rewarming. It is important to plan for prolonged resuscitation in these cases. Lastly, uncorrected ABG results should be used, without adjusting for temperature.

Further Reading:

Hypothermic cardiac arrest is a rare situation that requires a tailored approach. Resuscitation is typically prolonged, but the prognosis for young, previously healthy individuals can be good. Hypothermic cardiac arrest may be associated with drowning. Hypothermia is defined as a core temperature below 35ºC and can be graded as mild, moderate, severe, or profound based on the core temperature. When the core temperature drops, basal metabolic rate falls and cell signaling between neurons decreases, leading to reduced tissue perfusion. Signs and symptoms of hypothermia progress as the core temperature drops, initially presenting as compensatory increases in heart rate and shivering, but eventually ceasing as the temperature drops into moderate hypothermia territory.

ECG changes associated with hypothermia include bradyarrhythmias, Osborn waves, prolonged PR, QRS, and QT intervals, shivering artifact, ventricular ectopics, and cardiac arrest. When managing hypothermic cardiac arrest, ALS should be initiated as per the standard ALS algorithm, but with modifications. It is important to check for signs of life, re-warm the patient, consider mechanical ventilation due to chest wall stiffness, adjust dosing or withhold drugs due to slowed drug metabolism, and correct electrolyte disturbances. The resuscitation of hypothermic patients is often prolonged and may continue for a number of hours.

Pulse checks during CPR may be difficult due to low blood pressure, and the pulse check is prolonged to 1 minute for this reason. Drug metabolism is slowed in hypothermic patients, leading to a build-up of potentially toxic plasma concentrations of administered drugs. Current guidance advises withholding drugs if the core temperature is below 30ºC and doubling the drug interval at core temperatures between 30 and 35ºC. Electrolyte disturbances are common in hypothermic patients, and it is important to interpret results keeping the setting in mind. Hypoglycemia should be treated, hypokalemia will often correct as the patient re-warms, ABG analyzers may not reflect the reality of the hypothermic patient, and severe hyperkalemia is a poor prognostic indicator.

Different warming measures can be used to increase the core body temperature, including external passive measures such as removal of wet clothes and insulation with blankets, external active measures such as forced heated air or hot-water immersion, and internal active measures such as inhalation of warm air, warmed intravenous fluids, gastric, bladder, peritoneal and/or pleural lavage and high volume renal haemofilter.

Anaphylaxis, also known as anaphylactic shock, is characterized by certain symptoms similar to other types of shock. These symptoms include low blood pressure (hypotension), rapid heart rate (tachycardia), irregular heart rhythm (arrhythmia), changes in the electrocardiogram (ECG) indicating reduced blood flow to the heart (myocardial ischemia), such as ST elevation, and in severe cases, cardiac arrest.

Further Reading:

Anaphylaxis is a severe and life-threatening hypersensitivity reaction that can have sudden onset and progression. It is characterized by skin or mucosal changes and can lead to life-threatening airway, breathing, or circulatory problems. Anaphylaxis can be allergic or non-allergic in nature.

In allergic anaphylaxis, there is an immediate hypersensitivity reaction where an antigen stimulates the production of IgE antibodies. These antibodies bind to mast cells and basophils. Upon re-exposure to the antigen, the IgE-covered cells release histamine and other inflammatory mediators, causing smooth muscle contraction and vasodilation.

Non-allergic anaphylaxis occurs when mast cells degrade due to a non-immune mediator. The clinical outcome is the same as in allergic anaphylaxis.

The management of anaphylaxis is the same regardless of the cause. Adrenaline is the most important drug and should be administered as soon as possible. The recommended doses for adrenaline vary based on age. Other treatments include high flow oxygen and an IV fluid challenge. Corticosteroids and chlorpheniramine are no longer recommended, while non-sedating antihistamines may be considered as third-line treatment after initial stabilization of airway, breathing, and circulation.

Common causes of anaphylaxis include food (such as nuts, which is the most common cause in children), drugs, and venom (such as wasp stings). Sometimes it can be challenging to determine if a patient had a true episode of anaphylaxis. In such cases, serum tryptase levels may be measured, as they remain elevated for up to 12 hours following an acute episode of anaphylaxis.

The Resuscitation Council (UK) provides guidelines for the management of anaphylaxis, including a visual algorithm that outlines the recommended steps for treatment.
https://www.resus.org.uk/sites/default/files/2021-05/Emergency%20Treatment%20of%20Anaphylaxis%20May%202021_0.pdf

Cardiac enzymes do not increase in unstable angina. However, if cardiac markers do rise, it is classified as a non-ST elevation myocardial infarction (NSTEMI). Both unstable angina and NSTEMI can have a normal ECG. An extended ventricular activation time indicates damage to the heart muscle. This occurs because infarcting myocardium conducts electrical impulses at a slower pace, resulting in a prolonged interval between the start of the QRS complex and the apex of the R wave. A positive troponin test indicates the presence of necrosis in cardiac myocytes.

Summary:
Marker | Initial Rise | Peak | Normal at
Creatine kinase | 4-8 hours | 18 hours 2-3 days | CK-MB = main cardiac isoenzyme
Myoglobin | 1-4 hours | 6-7 hours | 24 hours | Low specificity due to skeletal muscle damage
Troponin I | 3-12 hours | 24 hours | 3-10 days | Appears to be the most sensitive and specific
HFABP | 1-2 hours | 5-10 hours | 24 hours | HFABP = heart fatty acid binding protein
LDH | 10 hours | 24-48 hours | 14 days | Cardiac muscle mainly contains LDH

Peripheral and central vertigo can be differentiated based on certain characteristics. Peripheral vertigo typically has a sudden onset and is associated with more severe symptoms of vertigo. The vertigo symptoms may come and go intermittently. Individuals with peripheral vertigo often experience severe nausea and vomiting. Their vertigo is also affected by head movement, particularly in certain positions. Peripheral vertigo is usually not accompanied by any focal neurology. Nystagmus, which is an involuntary eye movement, tends to occur away from the side of the lesion. In some cases, hearing may also be impaired, as seen in conditions like Meniere’s disease and labyrinthitis.

On the other hand, central vertigo tends to have a gradual onset and milder symptoms of vertigo. The vertigo symptoms are constant and do not fluctuate. Nausea and vomiting may be present but are usually less severe compared to peripheral vertigo. Unlike peripheral vertigo, central vertigo is not influenced by head movement and is considered fixed. Individuals with central vertigo may experience new-onset headaches. Additionally, central vertigo is often accompanied by focal neurology, indicating involvement of specific areas of the brain. Nystagmus in central vertigo occurs towards the side of the lesion. Unlike peripheral vertigo, hearing is typically unaffected in central vertigo cases.

The current gold standard for diagnosing Clostridium difficile colitis is the cytotoxin assay. However, this test has its drawbacks. It can be challenging to perform and results may take up to 48 hours to be available.

The most common laboratory test used to diagnose Clostridium difficile colitis is an enzyme-mediated immunoassay that detects toxins A and B. This test has a specificity of 93-100% and a sensitivity of 63-99%.

Stool culture, although expensive, is not specific for pathogenic strains and therefore cannot be relied upon for a definitive diagnosis of CDAD.

Sigmoidoscopy is not routinely used, but it may be performed in cases where a rapid diagnosis is needed or if the patient has an ileus. Approximately 50% of patients may exhibit the characteristic pseudomembranous appearance, which can be confirmed through a biopsy.

Abdominal X-ray and CT scanning are not typically used, but they can be beneficial in severe cases where complications such as perforation and toxin megacolon are suspected.

It is important to note that a barium enema should not be performed in patients with CDAD as it can be potentially harmful.

Congenital adrenal hyperplasia (CAH) is a group of inherited disorders that are caused by autosomal recessive genes. The majority of affected patients, over 90%, have a deficiency of the enzyme 21-hydroxylase. This enzyme is encoded by the 21-hydroxylase gene, which is located on chromosome 6p21 within the HLA histocompatibility complex. The second most common cause of CAH is a deficiency of the enzyme 11-beta-hydroxylase. The condition is rare, with an incidence of approximately 1 in 500 births in the UK. It is more prevalent in the offspring of consanguineous marriages.

The deficiency of 21-hydroxylase leads to a deficiency of cortisol and/or aldosterone, as well as an excess of precursor steroids. As a result, there is an increased secretion of ACTH from the anterior pituitary, leading to adrenocortical hyperplasia.

The severity of CAH varies depending on the degree of 21-hydroxylase deficiency. Female infants often exhibit ambiguous genitalia, such as clitoral hypertrophy and labial fusion. Male infants may have an enlarged scrotum and/or scrotal pigmentation. Hirsutism, or excessive hair growth, occurs in 10% of cases.

Boys with CAH often experience a salt-losing adrenal crisis at around 1-3 weeks of age. This crisis is characterized by symptoms such as vomiting, weight loss, floppiness, and circulatory collapse.

The diagnosis of CAH can be made by detecting markedly elevated levels of the metabolic precursor 17-hydroxyprogesterone. Neonatal screening is possible, primarily through the identification of persistently elevated 17-hydroxyprogesterone levels.

In infants presenting with a salt-losing crisis, the following biochemical abnormalities are observed: hyponatremia (low sodium levels), hyperkalemia (high potassium levels), metabolic acidosis, and hypoglycemia.

Boys experiencing a salt-losing crisis will require fluid resuscitation, intravenous dextrose, and intravenous hydrocortisone.

Affected females will require corrective surgery for their external genitalia. However, they have an intact uterus and ovaries and are capable of having children.

The long-term management of both sexes involves lifelong replacement of hydrocortisone (to suppress ACTH levels).

First-generation antipsychotics, also known as conventional or typical antipsychotics, are powerful blockers of the dopamine D2 receptor. However, each drug in this category has different effects on other receptors, such as serotonin type 2 (5-HT2), alpha1, histaminic, and muscarinic receptors.

These first-generation antipsychotics are known to have a high incidence of extrapyramidal side effects, which include rigidity, bradykinesia, dystonias, tremor, akathisia, tardive dyskinesia, and neuroleptic malignant syndrome (NMS). NMS is a rare and life-threatening reaction to neuroleptic medications, characterized by fever, muscle stiffness, changes in mental state, and dysfunction of the autonomic nervous system. NMS typically occurs shortly after starting or increasing the dose of neuroleptic treatment.

On the other hand, second-generation antipsychotics, also referred to as novel or atypical antipsychotics, are dopamine D2 antagonists, except for aripiprazole. These medications are associated with lower rates of extrapyramidal side effects and NMS compared to the first-generation antipsychotics. However, they have higher rates of metabolic side effects and weight gain.

It is important to note that serotonin syndrome shares similar features with NMS but can be distinguished by the causative agent, most commonly the serotonin-specific reuptake inhibitors.

Spontaneous bacterial peritonitis (SBP) is a serious infection that can occur in individuals with ascites, which is the accumulation of fluid in the abdominal cavity. In this case, the patient is a 42-year-old male intravenous drug user with a history of hepatitis C who has not received treatment. He presents to the emergency department with worsening abdominal distension, fever, and confusion.

To evaluate the patient, an abdominal paracentesis is performed, which involves removing a sample of the ascitic fluid for analysis. The findings from the ascitic fluid analysis can provide important information about the underlying cause of the patient’s symptoms.

In the given options, the finding that is indicative of spontaneous bacterial peritonitis (SBP) is an ascitic fluid absolute neutrophil count >250 cells/mm³. Neutrophils are a type of white blood cell that are typically elevated in the presence of infection. In SBP, there is an infection of the ascitic fluid, leading to an increase in neutrophils.

The other options provided do not specifically indicate SBP. An ascitic fluid absolute lymphocyte count >150 cells/mm³ may suggest a different type of infection or inflammation. An ascitic fluid absolute erythrocyte count >200 cells/mm³ may indicate bleeding into the ascitic fluid. An ascitic fluid albumin concentration of > 2.0 g/dL (20 g/L) and an ascitic fluid protein concentration of > 3.0 g/dL (30 g/L) may suggest liver disease or other causes of ascites, but they do not specifically indicate SBP.

Therefore, in this case, the presence of an ascitic fluid absolute neutrophil count >250 cells/mm³ is the finding that is indicative of spontaneous bacterial peritonitis (SBP).

Further Reading:

Cirrhosis is a condition where the liver undergoes structural changes, resulting in dysfunction of its normal functions. It can be classified as either compensated or decompensated. Compensated cirrhosis refers to a stage where the liver can still function effectively with minimal symptoms, while decompensated cirrhosis is when the liver damage is severe and clinical complications are present.

Cirrhosis develops over a period of several years due to repeated insults to the liver. Risk factors for cirrhosis include alcohol misuse, hepatitis B and C infection, obesity, type 2 diabetes, autoimmune liver disease, genetic conditions, certain medications, and other rare conditions.

The prognosis of cirrhosis can be assessed using the Child-Pugh score, which predicts mortality based on parameters such as bilirubin levels, albumin levels, INR, ascites, and encephalopathy. The score ranges from A to C, with higher scores indicating a poorer prognosis.

Complications of cirrhosis include portal hypertension, ascites, hepatic encephalopathy, variceal hemorrhage, increased infection risk, hepatocellular carcinoma, and cardiovascular complications.

Diagnosis of cirrhosis is typically done through liver function tests, blood tests, viral hepatitis screening, and imaging techniques such as transient elastography or acoustic radiation force impulse imaging. Liver biopsy may also be performed in some cases.

Management of cirrhosis involves treating the underlying cause, controlling risk factors, and monitoring for complications. Complications such as ascites, spontaneous bacterial peritonitis, oesophageal varices, and hepatic encephalopathy require specific management strategies.

Overall, cirrhosis is a progressive condition that requires ongoing monitoring and management to prevent further complications and improve outcomes for patients.

Cricoid pressure is applied during intubation to compress the oesophagus and prevent the backflow of stomach contents, reducing the risk of aspiration.

Further Reading:

Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.

Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.

Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.

Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.

Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.