Cushing’s Syndrome

•    Chronic excess cortisol

•    Features: weight gain, central obesity, purple striae, moon face, diabetes, hypertension, 

                                                                    osteoporosis, proximal myopathy, mood changes

•    Causes:

o    Exogenous steroids (most common)

o    ACTH-dependent: pituitary adenoma (Cushing’s disease), ectopic ACTH (e.g. small cell lung cancer)

o    ACTH-independent: adrenal adenoma/carcinoma

•    Diagnosis:

o    Initial tests: overnight dexamethasone suppression, 24-hour urinary free cortisol, 

                          late-night salivary cortisol

o    Confirmatory: high-dose dexamethasone suppression ± ACTH level

•    Treatment:

o    Surgical resection of tumour

o    Medical therapy: metyrapone, ketoconazole (if not suitable for surgery)

Addison’s Disease (Primary Adrenal Insufficiency)

•    Deficiency of cortisol and aldosterone

•    Features:  fatigue, weight loss, hyperpigmentation (↑ ACTH), 

                    postural hypotension, abdominal pain, salt craving

•    Electrolytes: ↓ Na⁺, ↑ K⁺, ↓ glucose, metabolic acidosis

•    Diagnosis:

o    First-line: short synacthen test (no cortisol rise after synthetic ACTH)

o    Baseline 9am cortisol and ACTH (↑ ACTH in primary)

•    Treatment:

o    Hydrocortisone (glucocorticoid) + fludrocortisone (mineralocorticoid)

o    Emergency: IV hydrocortisone + fluids for adrenal crisis

Primary Hyperaldosteronism (Conn’s Syndrome)

•    Autonomous aldosterone secretion → sodium retention, potassium loss

•    Features: hypertension, hypokalaemia, metabolic alkalosis

•    Diagnosis:

o    Screen with aldosterone:renin ratio (↑ aldosterone, ↓ renin)

o    Confirm with suppression tests

o    Localisation: adrenal CT scan ± adrenal vein sampling

•    Treatment:

o    Surgical: adrenalectomy for unilateral adenoma

o    Medical: spironolactone or eplerenone for bilateral hyperplasia

Congenital Adrenal Hyperplasia (CAH)

•    Most common: 21-hydroxylase deficiency

•    Features: ↓ cortisol ± ↓ aldosterone, ↑ ACTH, ↑ androgens

o    Females: ambiguous genitalia at birth

o    Males: early virilisation

•    Diagnosis: ↑ 17-hydroxyprogesterone

•    Treatment: lifelong hydrocortisone, mineralocorticoid replacement if needed

Adrenal Incidentaloma

•    Incidental adrenal mass on imaging

•    Must assess for:

o    Function:  cortisol (overnight dexamethasone test), metanephrines (phaeo), 

                        aldosterone:renin ratio (if hypertensive)

o    Malignancy risk: size >4 cm, irregular borders, non-homogeneous

•    Management:

o    Non-functional + benign appearance: monitor

o    Functional or suspicious: surgical excision