• 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)
• 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
• 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
• 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
• 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
General principles of hormone action
Hormonal physiology in health and disease
The hypothalamic-pituitary axis disorders
Adrenal disorders
Disorders of the adrenal medulla and MEN syndromes
Reproductive endocrinology and growth
Calcium, bone, and mineral metabolism
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Author & Educational Disclaimer
Author:
Dr Phillip Cockrell BM FRCP DipClinEd
Dr Phillip Cockrell is a UK Consultant Physician in Internal Medicine, currently working at Queen Alexandra Hospital, Portsmouth University Hospitals NHS Trust. He has previously worked as a registrar across Intensive Care Medicine, Gastroenterology, Cardiology, Stroke Medicine, Acute Medicine, and Respiratory Medicine.
He has held senior leadership roles including Associate Clinical Director of the Acute Medical Unit, Clinical Director of Internal Medicine, and Chief of Medicine. Dr Cockrell has over 15 years’ experience in postgraduate medical education, having lectured extensively across the MRCP syllabus and contributed to MRCP revision teaching and course development.
Dr Cockrell holds a Bachelor of Medicine (BM), Fellowship of the Royal College of Physicians (FRCP), and a Diploma in Clinical Education (DipClinEd). His teaching approach is based on structured consolidation of complex medical topics to support efficient and effective revision for postgraduate examinations.
Purpose of this content:
The material on this page is intended solely for educational purposes to support revision for the MRCP (UK) Part 1 examination. It reflects examination-relevant principles of internal medicine and is designed to aid learning and pattern recognition.
Medical disclaimer:
This content is designed for postgraduate medical examination revision and does not constitute medical advice, diagnosis, or treatment guidance and must not be used as a substitute for professional clinical judgement, local guidelines, or specialist consultation. Clinical decisions should always be made in the context of individual patient circumstances and current national guidance.
