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).

Acute closed-angle glaucoma is a serious eye condition that requires immediate medical attention. It occurs when the iris pushes forward and blocks the fluid from reaching the trabecular meshwork, which is responsible for draining the eye. This blockage leads to increased pressure inside the eye and can cause damage to the optic nerve.

The main symptoms of acute closed-angle glaucoma include severe eye pain, vision loss or decreased visual acuity, redness and congestion around the cornea, swelling of the cornea, a fixed semi-dilated pupil, and nausea and vomiting. Some individuals may also experience episodes of blurred vision or seeing haloes before the onset of these symptoms.

On the other hand, chronic open-angle glaucoma is a more common form of the condition. It affects about 1 in 50 people over the age of 40 and 1 in 10 people over the age of 75. In this type of glaucoma, there is a partial blockage in the trabecular meshwork, which gradually restricts the drainage of fluid from the eye. As a result, the pressure inside the eye gradually increases, leading to optic nerve damage. Unlike acute closed-angle glaucoma, chronic open-angle glaucoma does not cause eye pain or redness. Instead, it presents slowly with a gradual loss of peripheral vision, while central vision is relatively preserved.

It is important to seek medical attention if you experience any symptoms of glaucoma, as early diagnosis and treatment can help prevent further vision loss.

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 considered and 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.

Antipyretics, such as paracetamol, aspirin, and NSAIDs, do not have a role in the treatment of heat stroke. They work by interrupting the change in the hypothalamic set point caused by pyrogens, which is not the case in heat stroke where the hypothalamus is overwhelmed but functioning properly. In fact, antipyretics may be harmful in patients who develop complications in the liver, blood, and kidneys, as they can worsen bleeding tendencies.

Benzodiazepines, like diazepam, can be beneficial in patients experiencing agitation and/or shivering. They help reduce excessive heat production and agitation. In severe cases of agitation, paralysis may be necessary.

There are various cooling techniques recommended for the treatment of heat stroke, but currently, there is limited conclusive evidence on the most effective approach. Some possible methods include simple measures like consuming cold drinks, using fans, applying ice water packs, and spraying tepid water. Cold water immersion therapy can be helpful, but it requires the patient to be stable and cooperative, making it impractical for very sick 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.

Vascular dementia is not as common as Alzheimer’s disease, accounting for about 20% of dementia cases compared to 50% for Alzheimer’s. Most individuals with vascular dementia have a history of atherosclerotic cardiovascular disease and/or hypertension.

There are notable differences in how these two diseases present themselves. Vascular dementia often has a sudden onset, while Alzheimer’s disease has a slower onset. The progression of vascular dementia tends to be stepwise, with periods of stability followed by sudden declines, whereas Alzheimer’s disease has a more gradual decline. The course of vascular dementia can also fluctuate, while Alzheimer’s disease shows a steady decline over time.

In terms of personality and insight, individuals with vascular dementia tend to have relatively preserved personality and insight in the early stages, whereas those with Alzheimer’s disease may experience early changes and loss in these areas. Gait is also affected differently, with individuals with vascular dementia taking small steps (known as marche a petit pas), while those with Alzheimer’s disease have a normal gait.

Sleep disturbance is less common in vascular dementia compared to Alzheimer’s disease, which commonly presents with sleep disturbances. Focal neurological signs, such as sensory and motor deficits and pseudobulbar palsy, are more common in vascular dementia, while they are uncommon in Alzheimer’s disease.

To differentiate between Alzheimer’s disease and vascular dementia, the modified Hachinski ischemia scale can be used. This scale assigns scores based on various features, such as abrupt onset, stepwise deterioration, fluctuating course, nocturnal confusion, preservation of personality, depression, somatic complaints, emotional incontinence, history of hypertension, history of strokes, evidence of associated atherosclerosis, focal neurological symptoms, and focal neurological signs. A score of 2 or greater suggests vascular dementia.

Overall, understanding the differences in presentation and using tools like the modified Hachinski ischemia scale can help in distinguishing between Alzheimer’s disease and vascular dementia.

Epididymal cysts are commonly observed in men who are over the age of 40. They often appear in multiple numbers and can be found on both sides. These cysts are typically well-defined, soft to the touch, and can be illuminated when light is passed through them. Since they develop in the epididymis, they can be felt as separate from the testis, which helps to differentiate them from hydroceles. In most cases, these cysts cause no significant issues and do not require any treatment. However, larger cysts can become bothersome and may need to be drained or surgically removed.

Septic arthritis occurs when an infectious agent invades a joint, causing it to become purulent. The main symptoms of septic arthritis include pain in the affected joint, redness, warmth, and swelling of the joint, and difficulty moving the joint. Patients may also experience fever and systemic upset. The most common cause of septic arthritis is Staphylococcus aureus, but other bacteria such as Streptococcus spp., Haemophilus influenzae, Neisseria gonorrhoea, and Escherichia coli can also be responsible.

According to the current recommendations by NICE and the BNF, the initial treatment for septic arthritis is flucloxacillin. However, if a patient is allergic to penicillin, clindamycin can be used instead. If there is a suspicion of MRSA infection, vancomycin is the recommended choice. In cases where gonococcal arthritis or a Gram-negative infection is suspected, cefotaxime is the preferred treatment. The suggested duration of treatment is typically 4-6 weeks, although it may be longer if the infection is complicated.

Patients who have suffered burns should receive high-flow oxygen (15 L) through a reservoir bag while their breathing is being evaluated. If intubation is necessary, it is crucial to use an appropriately sized endotracheal tube (ETT). Using a tube that is too small can make it difficult or even impossible to ventilate the patient, clear secretions, or perform bronchoscopy.

According to the ATLS guidelines, adults should be intubated using an ETT with an internal diameter (ID) of at least 7.5 mm or larger. Children, on the other hand, should have an ETT with an ID of at least 4.5 mm. Once a patient has been intubated, it is important to continue administering 100% oxygen until their carboxyhemoglobin levels drop to less than 5%.

To protect the lungs, it is recommended to use lung protective ventilation techniques. This involves using low tidal volumes (4-8 mL/kg) and ensuring that peak inspiratory pressures do not exceed 30 cmH2O.

Neutropenic sepsis is a serious condition that can occur when a person has low levels of neutrophils, which are a type of white blood cell. This condition can be life-threatening and is often caused by factors such as chemotherapy, immunosuppressive drugs, infections, bone marrow disorders, and nutritional deficiencies.

To diagnose neutropenic sepsis, doctors look for a neutrophil count of 0.5 x 109 per litre or lower in patients undergoing cancer treatment. Additionally, patients must have a temperature higher than 38°C or show other signs and symptoms of significant sepsis.

According to the current guidelines from the National Institute for Health and Care Excellence (NICE), the recommended initial antibiotic treatment for suspected neutropenic sepsis is monotherapy with piperacillin with tazobactam (Tazocin 4.5 g IV). It is important to note that aminoglycosides should not be used as monotherapy or in combination therapy unless there are specific patient-related or local microbiological reasons to do so.

Vomiting is a common occurrence during the early stages of pregnancy, typically happening between 7 and 12 weeks. However, there is a more severe form called hyperemesis gravidarum, which affects less than 1% of pregnancies. This condition is characterized by uncontrollable and intense nausea and vomiting, leading to imbalances in fluids and electrolytes, significant ketonuria, nutritional deficiencies, and weight loss.

Hyperemesis gravidarum can result in electrolyte imbalances, particularly hyponatremia and hypokalemia. However, it does not cause hyperkalemia. This persistent vomiting can also lead to other complications such as dehydration, acidosis, deficiencies in vitamins B1, B12, and B6, Mallory-Weiss tears, retinal hemorrhages, pneumothorax, prematurity, and small-for-gestational age babies.

This individual has presented with haemoptysis and a purpuric rash, alongside a history of asthma and allergic rhinitis. Blood tests have revealed elevated inflammatory markers, pronounced eosinophilia, and acute renal failure. The most likely diagnosis in this case is Churg-Strauss syndrome.

Churg-Strauss syndrome is a rare autoimmune vasculitis that affects small and medium-sized blood vessels. The American College of Rheumatology has established six criteria for diagnosing Churg-Strauss syndrome. The presence of at least four of these criteria is highly indicative of the condition:

1. Asthma (wheezing, expiratory rhonchi)
2. Eosinophilia of more than 10% in peripheral blood
3. Paranasal sinusitis
4. Pulmonary infiltrates (which may be transient)
5. Histological confirmation of vasculitis with extravascular eosinophils
6. Mononeuritis multiplex or polyneuropathy

Churg-Strauss syndrome can affect various organ systems, with the most common clinical features including:

– Constitutional symptoms: fever, fatigue, weight loss, and arthralgia
– Respiratory symptoms: asthma, haemoptysis, allergic rhinitis, and sinusitis
– Cardiovascular symptoms: heart failure, myocarditis, and myocardial infarction
– Gastrointestinal symptoms: gastrointestinal bleeding, bowel ischaemia, and appendicitis
– Dermatological symptoms: purpura, livedo reticularis, and skin nodules
– Renal symptoms: glomerulonephritis, renal failure, and hypertension
– Neurological symptoms: mononeuritis multiplex

Investigations often reveal eosinophilia, anaemia, elevated CRP and ESR, elevated creatinine, and elevated serum IgE levels. Approximately 70% of patients test positive for p-ANCA.

The mainstay of treatment for Churg-Strauss syndrome is high-dose steroids. In cases with life-threatening complications, cyclophosphamide and azathioprine are often administered.

Polyarteritis nodosa is another vasculitic disorder that affects small and medium-sized blood vessels. It can impact the gastrointestinal tract, kidneys, skin, and joints, but it is not typically associated with rhinitis or asthma.