Diabetes mellitus, thyroid disorders, adrenal pathology, pituitary disease, calcium metabolism, and reproductive endocrinology.
Chronic excess of growth hormone (GH) in adults, almost always caused by a GH-secreting pituitary adenoma. Characterised by acral enlargement (hands, feet, jaw), coarsened facial features, and multi-organ complications. Diagnosed by failure to suppress GH on OGTT. Treated with transsphenoidal surgery, somatostatin analogues, or pegvisomant.
Primary adrenal insufficiency due to destruction of the adrenal cortex. Commonest cause in the UK is autoimmune adrenalitis (~80%). Characterised by cortisol and aldosterone deficiency with elevated ACTH. Presents with fatigue, weight loss, hyperpigmentation, and hypotension. Requires lifelong glucocorticoid and mineralocorticoid replacement.
Life-threatening medical emergency caused by acute cortisol deficiency. Presents with circulatory collapse, severe hypotension, and electrolyte disturbance. Commonest precipitant is intercurrent illness in a patient with known adrenal insufficiency who fails to increase steroid dose. Mortality ~0.5/100 patient-years. Treatment is immediate IV/IM hydrocortisone.
Clinical syndrome caused by systemic release of vasoactive substances (mainly serotonin) from neuroendocrine tumours, typically with hepatic metastases.
Group of autosomal recessive disorders of adrenal steroidogenesis. ~95% due to 21-hydroxylase deficiency. Results in cortisol deficiency with accumulation of precursors diverted to androgen pathway. Presents as classic (salt-wasting or simple virilising — neonatal) or non-classic (late-onset — adolescent/adult). Treated with glucocorticoid replacement.
Clinical syndrome resulting from chronic cortisol excess. Causes include exogenous steroids (commonest), pituitary adenoma (Cushing disease ~70% of endogenous), ectopic ACTH, and adrenal tumour. Characterised by central obesity, proximal myopathy, striae, and metabolic complications.
Disorder of water balance causing polyuria and polydipsia due to ADH deficiency (cranial DI) or renal resistance to ADH (nephrogenic DI). Cranial DI is treated with desmopressin; nephrogenic DI is treated by removing the cause and thiazide diuretics. Diagnosed by water deprivation test.
Major complication of diabetes leading to ulceration, infection, and amputation. UK: ~7,000 diabetes-related amputations per year. Caused by combination of peripheral neuropathy, peripheral arterial disease, and impaired immunity. Annual foot screening and prompt MDT management of ulcers are essential.
Life-threatening metabolic emergency characterised by hyperglycaemia, ketonaemia, and metabolic acidosis due to absolute or relative insulin deficiency. Most commonly occurs in type 1 diabetes. Mortality ~1% in UK. Managed with IV fluids, fixed-rate insulin infusion, and potassium replacement.
Leading cause of end-stage renal disease in the UK. Develops in ~30-40% of diabetic patients. Characterised by progressive albuminuria and declining GFR. ACE inhibitors/ARBs are the cornerstone of renoprotection. SGLT2 inhibitors provide additional renoprotective benefit (DAPA-CKD, CREDENCE trials).
Commonest cause of peripheral neuropathy in the UK. Affects ~50% of diabetic patients. Distal symmetric polyneuropathy is the predominant form. Major risk factor for diabetic foot ulceration and amputation. Prevention through glycaemic control is key (DCCT/UKPDS trials).
Commonest cause of blindness in working-age adults in the UK. Microvascular disease of the retina caused by chronic hyperglycaemia. Classified as non-proliferative (background, pre-proliferative) and proliferative. Screened by annual digital retinal photography. Treated with anti-VEGF injections, laser photocoagulation, and vitrectomy.
Glucose intolerance first identified during pregnancy. Affects ~4-5% of pregnancies in the UK. Risk factors include obesity, previous GDM, family history of diabetes, and South Asian/African-Caribbean ethnicity. Diagnosed by OGTT. Management: diet/exercise, then metformin, then insulin if targets not met.
Autoimmune thyroid disease caused by TSH receptor stimulating antibodies (TRAb). Commonest cause of hyperthyroidism (~75%). Characterised by diffuse goitre, thyrotoxicosis, orbitopathy, and rarely pretibial myxoedema. Treated with antithyroid drugs, radioiodine, or thyroidectomy.
Serum adjusted calcium >2.6 mmol/L. Two commonest causes account for ~90%: primary hyperparathyroidism (outpatient) and malignancy (inpatient). Presents with 'bones, stones, abdominal moans, and psychic groans'. Severe hypercalcaemia (>3.5 mmol/L) is a medical emergency. Treated with IV saline and IV bisphosphonates.
Life-threatening electrolyte disturbance defined as serum potassium >5.5 mmol/L, commonly caused by renal impairment, drugs (ACE inhibitors, spironolactone), and tissue breakdown. Requires urgent ECG assessment and treatment to prevent fatal cardiac arrhythmias.
Serum sodium >145 mmol/L indicating water deficit relative to sodium, most commonly due to inadequate water intake in elderly or unwell patients.
Life-threatening metabolic emergency of T2DM with severe hyperglycaemia (often >30 mmol/L), hyperosmolality (>320 mOsm/kg), and dehydration without significant ketoacidosis. Mortality ~15-20%. Managed with cautious IV fluids and low-dose insulin.
Excess thyroid hormone production causing a hypermetabolic state. Commonest cause is Graves disease (~75%). Presents with weight loss, heat intolerance, palpitations, tremor, and anxiety. Treated with antithyroid drugs, radioiodine, or surgery.
Serum adjusted calcium <2.1 mmol/L. Commonest causes are vitamin D deficiency and hypoparathyroidism (post-surgical). Presents with neuromuscular excitability — tetany, perioral paraesthesia, seizures. Severe hypocalcaemia with prolonged QT is a medical emergency requiring IV calcium gluconate.
Blood glucose <3.9 mmol/L in diabetic patients or <3.0 mmol/L in non-diabetic patients. Commonest acute complication of insulin and sulfonylurea therapy. Can be fatal if untreated. Causes adrenergic then neuroglycopaenic symptoms. Treated with fast-acting glucose or IM glucagon.
Serum potassium <3.5 mmol/L, commonly caused by diuretics, GI losses, or renal wasting, with risk of life-threatening cardiac arrhythmias if severe.
Most common electrolyte disorder, defined as serum sodium <135 mmol/L, requiring systematic assessment of volume status and osmolality to guide management.
Deficiency of PTH causing hypocalcaemia and hyperphosphataemia. Commonest cause is post-surgical (thyroid/parathyroid surgery). Also autoimmune or congenital (DiGeorge syndrome). Presents with neuromuscular excitability — tetany, paraesthesia, seizures. Treated with calcium and active vitamin D (alfacalcidol/calcitriol).
Partial or complete deficiency of anterior pituitary hormones (± posterior). Causes include pituitary adenoma, surgery, radiotherapy, Sheehan syndrome, and infiltrative disease. Presents with features of target organ hormone deficiency. Cortisol deficiency is most acutely dangerous. Requires lifelong hormone replacement.
Deficiency of thyroid hormones causing a generalised slowing of metabolic processes. Commonest cause in the UK is autoimmune (Hashimoto) thyroiditis. Affects ~2-5% of the population. Diagnosed by raised TSH with low free T4. Treated with levothyroxine replacement.
Condition characterised by insufficient testosterone production and/or impaired spermatogenesis due to testicular, pituitary, or hypothalamic dysfunction.
Cluster of interconnected metabolic risk factors including central obesity, insulin resistance, dyslipidaemia, and hypertension that increase cardiovascular disease risk.
Group of inherited autosomal dominant syndromes characterised by tumours in multiple endocrine glands, classified as MEN1, MEN2A, and MEN2B.
Rare life-threatening decompensation of severe hypothyroidism. Characterised by hypothermia, altered consciousness, bradycardia, and multi-organ dysfunction. Mortality ~25-60% even with treatment. Requires emergency IV levothyroxine and IV hydrocortisone.
Chronic disease defined by excess body fat accumulation (BMI ≥30 kg/m²) that impairs health, affecting approximately 28% of UK adults.
Metabolic bone disease characterised by defective bone mineralisation in adults, most commonly due to vitamin D deficiency, causing bone pain and proximal myopathy.
Systemic skeletal disease characterised by low bone density and microarchitectural deterioration leading to increased fracture risk. Affects ~3 million people in the UK. Commonest sites: vertebral, hip, and wrist. Diagnosed by DEXA scan (T-score ≤−2.5). Treated with bisphosphonates, calcium, and vitamin D.
Chronic bone disorder characterised by excessive and disorganised bone remodelling, most commonly affecting the pelvis, spine, skull, and long bones.
Catecholamine-secreting tumour arising from chromaffin cells of the adrenal medulla. Presents with episodic hypertension, headache, sweating, and palpitations. ~10% are extra-adrenal (paraganglioma), ~30-40% are hereditary. Diagnosed by elevated plasma/urine metanephrines. Treatment is surgical excision after alpha-blockade.
Common endocrine disorder in women of reproductive age characterised by hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology.
Loss of ovarian function before age 40, presenting with amenorrhoea, oestrogen deficiency, and elevated gonadotrophins, affecting approximately 1% of women.
Autonomous aldosterone secretion independent of the renin-angiotensin system. Commonest cause of secondary hypertension (~5-10% of hypertensive patients). Caused by adrenal adenoma (Conn syndrome ~35%) or bilateral adrenal hyperplasia (~60%). Presents with resistant hypertension and hypokalaemia. Diagnosed by raised aldosterone:renin ratio.
Excess PTH secretion from one or more parathyroid glands causing hypercalcaemia. Commonest cause of hypercalcaemia in the community. ~85% due to solitary parathyroid adenoma. Most patients are asymptomatic (detected incidentally). Definitive treatment is parathyroidectomy.
Commonest functioning pituitary adenoma (~40%). Prolactin-secreting tumour causing hyperprolactinaemia. Presents with galactorrhoea, amenorrhoea/oligomenorrhoea, reduced libido, and infertility. Microprolactinomas (<10mm) are common in women; macroprolactinomas (≥10mm) more common in men. First-line treatment is dopamine agonists (cabergoline), NOT surgery.
Commonest endocrine malignancy. Papillary carcinoma is the most frequent type (~80%) with excellent prognosis. Diagnosed by FNA cytology and treated with thyroidectomy ± radioiodine ablation ± TSH suppression. 10-year survival >95% for differentiated thyroid cancer.
Palpable or incidentally discovered lumps within the thyroid gland. Very common (~50% of adults on USS). The key clinical question is whether a nodule is malignant (~5% of nodules). Evaluated with TFTs, USS (U-classification), and fine needle aspiration cytology (Thy classification).
Life-threatening exacerbation of thyrotoxicosis with multi-organ decompensation. Mortality ~10-30% even with treatment. Typically precipitated by infection, surgery, or trauma in uncontrolled hyperthyroidism. Characterised by high fever, tachycardia, agitation, and organ failure. Requires emergency multi-modal treatment.
Inflammation of the thyroid gland with multiple aetiologies. Subacute (de Quervain) thyroiditis presents with painful thyroid and transient thyrotoxicosis. Postpartum thyroiditis affects ~5% of women. Hashimoto thyroiditis is covered under hypothyroidism.
Chromosomal disorder affecting females characterised by complete or partial absence of one X chromosome (45,X), causing short stature, ovarian failure, and congenital anomalies.
Autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency. Requires lifelong insulin therapy. Typically presents in childhood/young adulthood with polyuria, polydipsia, weight loss, and ketonaemia. UK prevalence ~400,000. Managed with basal-bolus insulin or insulin pump therapy.
Progressive metabolic disorder characterised by insulin resistance and relative insulin deficiency. Commonest form of diabetes (~90%). Strong association with obesity and sedentary lifestyle. UK prevalence ~4.3 million (including undiagnosed). Managed with lifestyle modification and stepwise pharmacotherapy targeting HbA1c.