Addison’s disease is most commonly caused by autoimmune destruction in the UK, accounting for up to 80% of cases. Therefore, it is crucial to screen individuals with Addison’s for other autoimmune conditions like thyroid diseases and diabetes. Congenital adrenal hyperplasia is a rare cause of Addison’s that typically presents in childhood with symptoms such as failure to thrive and grow. While tuberculosis is the most common cause of Addison’s worldwide, it is not the primary cause in the UK. Adrenal haemorrhage, which can result from severe bacterial infections like meningococcal, can also lead to Addison’s disease in a condition known as Waterhouse-Friderichsen syndrome. Finally, metastatic cancer is a rare but significant cause of addisonism.

Functions of Digestive Enzymes and Hormones

Amylase is an enzyme that aids in the digestion of carbohydrates. It is present in both pancreatic juices and saliva. The exocrine function of the pancreas involves the secretion of substances into ducts that ultimately pass to the exterior of the body. Examples of exocrine glands include sweat glands, salivary glands, and mammary glands. On the other hand, the endocrine function of the pancreas involves the secretion of substances directly into the bloodstream. Insulin, which is secreted from the beta cells of the islets of Langerhans of the pancreas, is an example of an endocrine function.

Bile is another substance that aids in digestion. It is secreted by hepatocytes and stored in the gallbladder. Following a meal, bile is released to aid in the digestion of fats. Intrinsic factor, which is secreted by the parietal cells of the stomach, is responsible for binding vitamin B12 to allow its absorption in the terminal ileum. Finally, noradrenaline is a hormone that is released by the adrenal medulla. It plays a role in the body’s fight or flight response.

In summary, the digestive system relies on a variety of enzymes and hormones to function properly. These substances are secreted by various glands and organs throughout the body, and they work together to break down food and absorb nutrients.

Management of Reifenstein Syndrome: Hormonal and Surgical Options

Reifenstein syndrome is a rare X-linked genetic disease that results in partial androgen insensitivity. In phenotypic males with this condition, testosterone replacement therapy is recommended to increase the chances of fertility. However, if the patient had been raised as a female and chose to continue this way, oestrogen replacement therapy would be appropriate. Surgical management may be necessary if the patient has undescended testes, but in this case, orchidectomy is not indicated as the patient has small testes in the scrotum. While psychological counselling is always necessary, it is not the first line of treatment. Overall, the management of Reifenstein syndrome involves a combination of hormonal and surgical options tailored to the individual patient’s needs.

HbA1c as a Tool for Glycaemic Control

The glycated haemoglobin (HbA1c) is a measure of the glucose levels in the blood over a period of time. It reflects the glycosylation of the haemoglobin molecule by glucose, and there is a strong correlation between the glycosylation of this molecule and average plasma glucose concentrations. This makes it a widely used tool in clinical practice to assess glycaemic control. Studies have also shown that HbA1c has prognostic significance in both microvascular and macrovascular risk.

The life span of a red blood cell is 120 days, and HbA1c reflects the average blood glucose levels during the half-life of the red cell, which is about 60 days. According to NICE guidelines, it is recommended to re-check HbA1c with each treatment intensification at 3/6 monthly intervals. HbA1c as a tool for glycaemic control is crucial in managing diabetes and reducing the risk of complications.

Differential Diagnosis: Addisonian Crisis and Other Conditions

Addisonian crisis is a condition caused by adrenal insufficiency, with autoimmune disease being the most common cause in the UK. Symptoms are vague and present insidiously, including depression, anorexia, and GI upset. Diagnosis is made through a short ACTH stimulation test. Emergency treatment involves IV hydrocortisone and fluids, while long-term treatment is based on oral cortisol and mineralocorticoid. Any stressful activity should lead to an increase in steroid dose.

Other conditions, such as insulin overdose, salicylate overdose, meningococcal septicaemia, and paracetamol overdose, have different clinical features and are not compatible with the symptoms described for Addisonian crisis. It is important to consider these differential diagnoses when evaluating a patient with similar symptoms.

Thyroid Disorders and their Differentiation

Thyroid disorders are a common occurrence, and their diagnosis is crucial for effective treatment. One such disorder is Graves’ disease, which is characterized by a goitre with a bruit. Unlike MNG, Graves’ disease is associated with angiogenesis and thyroid follicular hypertrophy. Other signs of Graves’ disease include eye signs such as conjunctival oedema, exophthalmos, and proptosis. Additionally, pretibial myxoedema is a dermatological manifestation of this disease.

De Quervain’s thyroiditis is another thyroid disorder that follows a viral infection and is characterized by painful thyroiditis. Hashimoto’s thyroiditis, on the other hand, is a chronic autoimmune degradation of the thyroid. Multinodular goitre (MNG) is the most common form of thyroid disorder, leading to the formation of multiple nodules over the gland. Lastly, a toxic thyroid nodule is a solitary lesion on the thyroid that produces excess thyroxine.

In conclusion, the different types of thyroid disorders and their symptoms is crucial for accurate diagnosis and effective treatment.

The Effects of PTH on Bone and Kidney

Parathyroid hormone (PTH) has two main targets in the body: the bone and the kidney. Its primary goal in the bone is to increase calcium levels by stimulating the activity of osteoclasts, which break down bone tissue to release calcium into the bloodstream. In the kidney, PTH has a different effect. It increases the reabsorption of calcium and decreases the absorption of phosphate, which helps to maintain the balance of these minerals in the body. Additionally, PTH stimulates the production of 1-alpha hydroxylation of vitamin D in the kidney, which is important for calcium absorption and bone health. Overall, PTH plays a crucial role in regulating calcium and phosphate levels in the body, and its effects on bone and kidney function are essential for maintaining healthy bones and overall health.

Factors affecting bone age in children

Bone age, which refers to the degree of maturation of a child’s bones, can be influenced by various factors. In a child with normal thyroid function, bone age would be expected to be normal if they are receiving adequate treatment. However, in cases of growth hormone deficiency, bone age may be delayed. On the other hand, in cases of exogenous obesity resulting from over-nutrition and lack of exercise, bone age may be advanced.

If a child has an underlying endocrine disorder such as hypothyroidism, their bone age may be delayed. Turner’s syndrome, a genetic disorder affecting females, is also associated with delayed bone age by approximately 2 years during childhood. Conversely, congenital adrenal hyperplasia and central precocious puberty can cause advanced bone age.

In summary, bone age can be affected by various factors, including thyroid function, growth hormone deficiency, obesity, endocrine disorders, and genetic conditions. these factors can help healthcare providers assess a child’s growth and development and provide appropriate treatment if necessary.

Hormones of the Hypothalamus

The hypothalamus produces several hormones that regulate various bodily functions. These hormones include thyrotrophic-releasing hormone (TRH), gonadotrophin-releasing hormone (GnRH), growth hormone-releasing hormone (GHRH), corticotrophin-releasing hormone (CRH), antidiuretic hormone (also known as vasopressin), dopamine (prolactin-inhibiting hormone), somatostatin (growth hormone-inhibiting hormone), and oxytocin.

CRH is responsible for regulating the release of adrenocorticotrophic hormone (ACTH) from the anterior pituitary. Oxytocin is produced by the cells in the paraventricular nucleus and secreted from the posterior pituitary. These hormones play a crucial role in maintaining homeostasis in the body. By regulating the release of other hormones, they help to control various bodily functions such as growth, metabolism, and reproduction.

In summary, the hormones of the hypothalamus are essential for maintaining the proper functioning of the body. They work together to regulate the release of other hormones and ensure that bodily functions are kept in balance.

Papillary thyroid carcinoma is the most common type of thyroid cancer and has a good prognosis. It is characterized by ground-glass or Orphan Annie nuclei with calcified spherical bodies. Medullary thyroid carcinoma can occur sporadically or as part of multiple endocrine neoplasia syndromes and arises from the parafollicular C cells. Lymphoma of the thyroid is a rare cancer, except in individuals with Hashimoto’s thyroiditis. Anaplastic thyroid carcinoma is a highly aggressive form of thyroid cancer with a poor prognosis. Follicular thyroid carcinoma presents with a microfollicular pattern and is difficult to diagnose on fine-needle aspiration alone.

Understanding Addison’s Disease: Hormonal Imbalances and Clinical Presentation

Addison’s disease, or primary adrenal failure, is a condition characterized by autoimmune destruction of the adrenal cortex, resulting in reduced levels of cortisol and aldosterone. This hormonal imbalance leads to a range of clinical symptoms, including hypotension, hyponatraemia, hyperkalaemia, acidosis, and skin and mucosal hyperpigmentation.

While other hormonal imbalances may occur in the adrenal glands, such as increased cortisol or aldosterone, they are less likely to result in the clinical presentation of Addison’s disease. For example, increased cortisol is unlikely due to autoimmune destruction of the zona fasciculata, while increased aldosterone is rare and typically caused by an adrenal adenoma. Similarly, decreased cortisol with normal aldosterone is more commonly associated with secondary adrenal failure caused by pituitary disease, but does not fit with the hyponatraemia seen in Addison’s disease.

Overall, understanding the hormonal imbalances and clinical presentation of Addison’s disease is crucial for accurate diagnosis and effective treatment.

Hypertension Management in Type 2 Diabetes Patients

Patients with type 2 diabetes who have inadequately controlled hypertension should be prescribed an ACE inhibitor, which is the preferred antihypertensive medication for diabetes. Combining an ACE inhibitor with a calcium channel blocker like amlodipine can also be effective. However, beta-blockers should be avoided for routine hypertension treatment in diabetic patients. Methyldopa is a medication used specifically for hypertension during pregnancy, while moxonidine is reserved for cases where other medications have failed to control blood pressure. If blood pressure control is still insufficient with ramipril and amlodipine, a thiazide diuretic can be added to the treatment plan.

It is important to note that hypertension management in diabetic patients requires careful consideration of medication choices and potential interactions. Consulting with a healthcare provider is crucial to ensure safe and effective treatment. Further reading on this topic can be found in the Harvard Medical School’s article on medications for treating hypertension.

Differential diagnosis of a patient with hyperprolactinaemia, headaches, visual field defects, and hypogonadism

Prolactinoma, idiopathic panhypopituitarism, craniopharyngioma, isolated LH deficiency, and pituitary infarction are among the possible diagnoses for a patient presenting with hyperprolactinaemia, headaches, visual field defects, and hypogonadism. Prolactinomas are the most common functional pituitary tumours and can cause local effects on the optic chiasm and hypothalamus-pituitary-gonadal axis. Idiopathic panhypopituitarism would result in decreased levels of all anterior pituitary hormones, including prolactin. Craniopharyngioma, more common in children and adolescents, can lead to hypopituitarism but rarely causes hyperprolactinaemia. Isolated LH deficiency could explain the loss of libido and decreased plasma levels of LH and testosterone, but not the increase in prolactin or bitemporal hemianopia. Pituitary infarction, such as in Sheehan syndrome, can cause varying degrees of hypopituitarism but not hyperprolactinaemia. A thorough evaluation of the patient’s clinical and laboratory findings, imaging studies, and medical history is necessary to establish the correct diagnosis and guide the appropriate treatment.

Diagnosis and Management of Primary Hypothyroidism

The patient’s test results indicate a case of primary hypothyroidism, characterized by low levels of thyroxine (T4) and elevated thyroid-stimulating hormone (TSH). The most likely cause of this condition is Hashimoto’s thyroiditis, which is often accompanied by the presence of thyroid peroxidase antibodies. While the patient has a goitre, it appears to be smooth and non-threatening, so a thyroid ultrasound is not necessary. Additionally, a radio-iodine uptake scan is unlikely to show significant uptake and is therefore not recommended. Positive TSH receptor antibodies are typically associated with Graves’ disease, which is not the likely diagnosis in this case. For further information on Hashimoto’s thyroiditis, patients can refer to Patient.info.

Thyroid Function Tests: Understanding the Results

Thyroid function tests are commonly used to diagnose and monitor thyroid disorders. The results of these tests can provide valuable information about the functioning of the thyroid gland. Here are some common thyroid function test results and what they may indicate:

Poor Compliance with Thyroxine
Patients who are not compliant with their thyroxine medication may only take it a few days before a routine blood test. This can result in normal thyroxine levels due to the supplementation, but the TSH levels may not have enough time to reach the normal range due to the required negative feedback.

Sick Euthyroid Syndrome
In this condition, all TSH, thyroxine, and T3 levels are low. However, the TSH level is often within the normal range. This condition is reversible upon recovery from the systemic illness.

Thyrotoxicosis
Thyrotoxicosis is characterized by low TSH and high T4 levels.

Primary Hypothyroidism
Primary hypothyroidism results in low T4 levels and subsequent high TSH levels due to negative feedback.

Secondary Hypothyroidism
In secondary hypothyroidism, both TSH and T4 levels are low. This condition occurs due to the failure of the anterior pituitary to secrete TSH despite adequate thyrotropin-releasing hormone (TRH) levels. TRH is elevated, but TSH, T3, and T4 are low, and TSH fails to rise even after a TRH stimulation test.

Understanding the results of thyroid function tests can help healthcare providers diagnose and manage thyroid disorders effectively.

Peptides Secreted by the Pituitary Gland

The pituitary gland secretes various hormones that regulate different bodily functions. The posterior lobe of the pituitary gland secretes two peptides, oxytocin and antidiuretic hormone (ADH). Oxytocin, which is produced in the hypothalamus, stimulates uterine contractions during labor and is involved in the release of milk from the lactating breast. ADH, also known as vasopressin, is also produced in the hypothalamus and regulates water balance in the body.

On the other hand, the anterior lobe of the pituitary gland secretes six peptide hormones. These hormones include adrenocorticotrophic hormone (ACTH), prolactin, thyroid-stimulating hormone (TSH), growth hormone (GH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH). ACTH stimulates the adrenal gland to produce cortisol, which helps the body respond to stress. Prolactin stimulates milk production in the mammary glands. TSH stimulates the thyroid gland to produce thyroid hormones, which regulate metabolism. GH promotes growth and development in children and helps maintain muscle and bone mass in adults. FSH and LH regulate the reproductive system, with FSH stimulating the growth of ovarian follicles in females and sperm production in males, while LH triggers ovulation in females and testosterone production in males.

The levels of TSH, free T4, and free T3 can provide insight into the functioning of the thyroid gland. High TSH and low free T4 and free T3 levels suggest Hashimoto’s thyroiditis, a type of autoimmune primary hypothyroidism. Low TSH and high free T4 and free T3 levels indicate primary hyperthyroidism, such as Graves’ disease. Low TSH and low free T4 and free T3 levels suggest secondary or tertiary hypothyroidism. High TSH and normal free T4 and free T3 levels suggest subclinical hypothyroidism, which may progress to primary hypothyroidism. Low TSH and normal free T4 and free T3 levels suggest subclinical hyperthyroidism, which may progress to primary hyperthyroidism.

The causes of Gynaecomastia are varied and can be indicative of underlying health issues. This condition is characterized by the enlargement of male breast tissue, which is caused by an imbalance in the testosterone to oestradiol ratio. It is important to note that hyperprolactinaemia and hypopituitarism do not affect this ratio and are not commonly associated with gynaecomastia.

It is also important to note that hypothyroidism and CAH are not known to cause this condition. However, gynaecomastia can be a symptom of seminoma, a type of testicular cancer, due to the secretion of human chorionic gonadotropin (HCG). Therefore, seeking medical attention if gynaecomastia is present is crucial.

Prolactinoma, on the other hand, is a benign tumour of the pituitary gland that is typically asymptomatic. It is not known to cause gynaecomastia, but it is important to monitor its growth and seek medical attention if any symptoms arise. Understanding the causes of gynaecomastia can help individuals identify potential health issues and seek appropriate treatment.

Differentiating Primary Hyperaldosteronism from Other Causes of Hypertension

Primary hyperaldosteronism, also known as Conn’s syndrome, is a condition characterized by elevated aldosterone levels leading to low renin levels through negative feedback loops. This is the primary cause of hypertension in this condition. On the other hand, secondary hypertension can be caused by various conditions such as acromegaly, Cushing’s syndrome, and phaeochromocytoma. However, these conditions are not associated with low renin and elevated aldosterone levels. Renal artery stenosis, on the other hand, causes both high renin and aldosterone levels, leading to secondary hyperaldosteronism. Therefore, differentiating primary hyperaldosteronism from other causes of hypertension is crucial in determining the appropriate treatment plan.

High Serum Calcium Levels

When analyzing blood test results, a high serum calcium level in combination with a low phosphate level, high serum alkaline phosphatase (ALP), and normal glomerular filtration rate (GFR) may indicate primary hyperparathyroidism. While the parathyroid hormone (PTH) may fall within the reference range, it is considered inappropriate for the high calcium levels, as it should be suppressed as part of the negative feedback mechanism. It is important to note that a result within the reference range may still be abnormal.

Primary hyperparathyroidism is typically caused by a solitary adenoma, hyperplasia of all the parathyroid glands, multiple adenomas, or parathyroid carcinoma. Other conditions, such as vitamin D excess or bony metastases, may also cause high calcium levels, but the PTH would be suppressed if it were the primary pathology. Severe hypercalcemia can lead to dehydration, but dehydration itself would not cause such high serum calcium levels. Sclerosing cholangitis may cause elevated ALP levels of liver origin, but it would not explain the other results. the potential causes of high serum calcium levels can aid in proper diagnosis and treatment.

Cholesterol Metabolism: Deficiencies and High Levels of Key Proteins

Apo B-100 is a protein that binds to LDL receptors, allowing for the uptake of lipoproteins. A deficiency in apo B-100 or LDL receptors can lead to familial hypercholesterolemia and an accumulation of cholesterol.

Lipoprotein lipase is an enzyme that breaks down chylomicrons and VLDLs. A deficiency in this enzyme can result in the accumulation of both, but with normal or slightly raised cholesterol levels.

ACAT is an enzyme that catalyzes the re-synthesis of cholesterol esters. A deficiency in ACAT would lead to reduced plasma cholesterol levels.

High levels of HDL are protective as they increase cholesterol transport from tissues to the liver for conversion to bile acids and excretion in feces. However, high levels of HDL are rare.

LCAT is an enzyme that converts cholesterol taken up by HDL into a cholesterol ester, which is then transferred to lipoprotein remnants for uptake by the liver. High levels of LCAT can increase reverse cholesterol transport and reduce plasma cholesterol levels.

Common Musculoskeletal Conditions: Osteomalacia, Tuberculosis, Osteoporosis, Osteogenesis Imperfecta, and Osteosarcoma

Osteomalacia is a condition that occurs due to vitamin D deficiency or defects in phosphate metabolism, resulting in soft bones. Patients may experience bone and joint pain, muscle weakness, or fractures. Treatment involves vitamin D or calcium supplementation, braces, or surgery.

Tuberculosis can affect the musculoskeletal system, particularly the spine and weightbearing joints. Extrapulmonary tuberculosis can cause a pathological fracture, but osteomalacia is more likely in this case.

Osteoporosis is a metabolic bone disease that commonly affects patients over 50 years old. It results from an imbalance in bone formation and resorption, leading to osteoporotic fractures from low energy trauma.

Osteogenesis imperfecta is a congenital disease characterized by easily fractured bones, bone deformities, and bowed legs and arms. It is caused by mutations in collagen type 1.

Osteosarcoma is a primary bone tumor that frequently presents in children and young adults. Symptoms include bone pain and tissue swelling or mass, most commonly affecting the knee joint.

Adrenocortical Tumour: Localizing the Source of Excessive Cortisol Production

Cushing’s syndrome is characterized by the overproduction of glucocorticoids, which can lead to weight gain, mood disturbances, and irregular menses. In this case, the patient has proven high 24-hour urinary cortisol excretion, indicating excessive cortisol levels. However, the lack of response to low-dose dexamethasone and the low potassium and high sodium levels suggest that an adrenocortical tumour is the most likely cause.

An adrenocortical tumour results in excess cortisol secretion by the adrenal glands, leading to negative feedback at the pituitary level and very low or undetectable levels of ACTH. This is consistent with the patient’s presentation, ruling out Cushing’s disease, Conn’s syndrome, and acromegaly. Additionally, the absence of detectable ACTH levels rules out paraneoplastic syndrome secondary to small cell carcinoma of the lung.

In conclusion, the patient’s clinical picture and test results suggest an adrenocortical tumour as the source of excessive cortisol production.

Prolactinomas cause amenorrhoea, infertility, and galactorrhoea. If the tumour extends outside the sella, visual field defects or other mass effects may occur. Other types of tumours will produce different symptoms depending on their location and structure involved. Craniopharyngiomas originate from the pituitary gland and will produce poralhemianopia if large enough, as well as symptoms related to pituitary hormones. Non-functioning pituitary tumours will have similar symptoms without the pituitary hormone side effects. Tumours of the hypothalamus will present with symptoms of euphoria, headache, weight loss, and mass effect if large enough.

Managing Hypothyroidism in Pregnancy: Recommendations for Levothyroxine Dosing and Thyroid Function Testing

Hypothyroidism in pregnancy requires careful management to ensure optimal outcomes for both the mother and fetus. The National Institute for Health and Care Excellence (NICE) guidelines recommend increasing the dose of levothyroxine by 25-50 μg and referring the patient to an endocrinologist upon diagnosis of pregnancy. It is important to note that iodine supplements are not recommended for treating hypothyroidism in pregnancy. Adequate thyroid function is crucial for fetal neurological development, so stopping levothyroxine is not an option. Thyroid function tests (TFTs) should be taken at baseline and every four weeks, as changes in drug pharmacodynamics and kinetics can occur during pregnancy. The target thyroid stimulating hormone range should be low-normal at 0.4-2 mU/l, and the dose of levothyroxine should remain unchanged until specialist review.

Medical Conditions: Addison’s Disease and Other Differential Diagnoses

Addison’s Disease:
Addison’s disease, or primary hypoadrenalism, is a condition characterized by chronic adrenal insufficiency. The most common cause in the UK is autoimmune destruction of the adrenals, while worldwide tuberculosis is the most common cause. Other causes include long-term exogenous steroid use, cancer, or haemorrhage damage. Symptoms develop gradually, but patients can present in Addisonian crisis if there is a sudden deterioration in adrenal function or a physiological stress that the residual adrenal function is not capable of coping with. Treatment is with long-term replacement of corticosteroids and aldosterone. Treatment of a crisis requires intravenous glucocorticoids, as well as supportive measures and fluid resuscitation.

Differential Diagnoses:
Peutz–Jeghers syndrome is an autosomal dominant condition characterized by perioral freckling and small bowel polyps. Insulinoma causes hypoglycaemia, but the other features are absent. Cushing syndrome is a result of excess corticosteroid, while Conn syndrome is also known as primary hyperaldosteronism.

Testicular Lesions and Gynaecomastia in Young Males

This young male is presenting with tender gynaecomastia and a suspicious testicular lesion. The most likely diagnosis in this age group is a teratoma, as seminoma tends to be more common in older individuals. Gynaecomastia can be a presenting feature of testicular tumours, as the tumour may secrete beta HCG. Other tumour markers of teratoma include alphafetoprotein (AFP).

It is important to note that testicular lymphoma typically presents in individuals over the age of 40 and would not be associated with gynaecomastia. Therefore, in young males presenting with gynaecomastia and a testicular lesion, a teratoma should be considered as a possible diagnosis. Early detection and treatment are crucial for the best possible outcome.

Targeting Hormones in Prolactinoma Treatment

Prolactinoma is a pituitary lesion that results in excessive prolactin secretion. To reduce prolactin levels, dopamine agonists like bromocriptine are used. While there are other hormones that can affect prolactin secretion, they are not therapeutic targets in prolactinoma treatment. Corticotropin-releasing hormone (CRH) increases adrenocorticotropic hormone secretion, while gonadotropin-releasing hormone (GnRH) can indirectly decrease GnRH secretion. Somatostatin decreases thyroid-stimulating hormone and growth hormone secretion, but does not affect prolactin. Thyrotropin-releasing hormone (TRH) increases prolactin and TSH release, but is not a therapeutic target due to its effects on thyroid regulation and the superiority of dopamine agonists.

Possible Causes of Chronic Abdominal Pain

Chronic abdominal pain can be caused by reduced blood flow to the bowel, which can lead to a pain similar to angina. This condition is more common in patients with diabetes mellitus, as atherosclerosis can affect the major arteries to the bowel. Acute pancreatitis is not a likely cause of this pain, as it would cause acute and severe abdominal pain, unrelated to meals. Aortic aneurysm can also be a consequence of atherosclerosis, and an abdominal mass may be palpated on examination. However, typically there is no pain until the aneurysm ruptures, which is a surgical emergency. Chronic renal failure, which is one of the main causes of diabetes, would not cause meal-related abdominal pain, and we are not told any serum electrolyte values to indicate this. Hepatic infarction, which refers to diffuse hepatic injury from acute hypoperfusion resulting from obstruction of the arterial circulation or more rarely the portal venous circulation, is rare due to the liver’s dual blood supply. Causes of hepatic infarction include atherosclerotic occlusion, embolus, arthritis of the hepatic artery, neoplastic invasion by malignant tumors in the liver hilus, and hypercoagulation states, such as polycythemia.

Congenital adrenal hyperplasia is a group of genetic conditions that affect the production of hormones and steroids from the adrenal glands. The most common cause is a deficiency in the enzyme 21-hydroxylase. This leads to overactivity of the steroid-producing cells and inadequate cortisol production, resulting in an excess of mineralocorticoids and androgens/oestrogens. Symptoms can include ambiguous genitalia at birth in females, hyperpigmentation and penile enlargement in males, and biochemical abnormalities such as hyponatraemia and hyperkalaemia. Treatment involves hormone replacement therapy. Addisonian crisis is a potentially fatal episode caused by glucocorticoid and mineralocorticoid deficiency, usually occurring in adulthood and precipitated by stress. It presents with hyponatraemia, hyperkalaemia, hypoglycaemia and hypercalcaemia, and is managed with urgent administration of glucocorticoids. Conn syndrome is associated with primary hyperaldosteronism and presents with hypernatraemia and hypokalaemia. Cushing syndrome is due to cortisol excess and presents with weight gain, hypertension, oedema, hyperglycaemia, hypokalaemia and skin pigmentation. Thyrotoxic crisis is a life-threatening condition associated with excessive production of thyroid hormones, presenting with a range of symptoms including tachycardia, hypertension, fever, poor feeding, weight loss, diarrhoea, nausea, vomiting, seizures and coma. Prompt treatment is essential to prevent serious complications.