Acromegaly in MRCP PACES: spot diagnosis, signs and viva

How it presents in PACES

Acromegaly is growth hormone excess after the epiphyses have fused (before fusion it produces gigantism), almost always from a GH-secreting pituitary adenoma — a somatotroph adenoma. In PACES it lives in a consultation station as a classic "spot diagnosis plus list the complications" case, and the same physiology drives several consultation-station stems: bilateral carpal tunnel, obstructive sleep apnoea, resistant young hypertension, or simply tiredness.

The whole game is to recognise it early and then behave like it is the unifying diagnosis, not to stop at whichever complication opened the door. What walks in is a patient with coarse facies — heavy brow, broad fleshy nose, thick lips — and large, doughy, spade-like hands you often notice as you shake hands. Announce the gestalt, then earn the marks by systematically confirming the individual signs and screening every organ the disease touches.

Be alert to the anchoring trap. If the candidate before you was told "the numb hands are diabetic neuropathy", they will have missed it. The examiner is watching whether you connect the hands, the snoring, the blood pressure and the face into one endocrine story.

Signs to look for

Work end-of-bed inwards. This focused checklist is where the marks sit:

• Face: frontal bossing, prominent supraorbital ridges, broad nose, thickened greasy skin and lips.
• Jaw and mouth: prognathism (protruding lower jaw), malocclusion, widened interdental spacing, and macroglossia with dental indentation marks along the tongue margins.
• Hands: large, broad, spade-like and doughy; feel for a sweaty, thickened palm; look for OA-type arthropathy. The ring-no-longer-fits history is a useful clue.
• Carpal tunnel syndrome: positive Tinel's/Phalen's, reduced pinprick over the lateral three and a half digits, with characteristic sparing of thenar (palmar) skin sensation — the palmar cutaneous branch of the median nerve arises proximal to the tunnel, so its territory is spared. Check abductor pollicis brevis power and thenar bulk.
• Eyes (say-and-do): test visual fields to confrontation for a bitemporal hemianopia from chiasmal compression, and offer fundoscopy for hypertensive change, optic atrophy or papilloedema. Mention angioid streaks as an associated retinal sign.
• Complete the survey: neck for goitre, axillae for skin tags and acanthosis nigricans, chest for gynaecomastia, proximal myopathy, a displaced apex, and lower-limb OA or bowing. Look for a trans-frontal or trans-sphenoidal surgical scar signalling treated disease.

Confirming the diagnosis and differential

The bedside diagnosis is clinical, but say how you would confirm it biochemically. The gold standard is an oral glucose tolerance test with serial GH: failure of GH to suppress below roughly 1 ng/mL after 75 g of glucose is diagnostic, and the OGTT conveniently screens for diabetes at the same time. A single random GH is unreliable because secretion is pulsatile. IGF-1 (age- and sex-adjusted) is the screening test and the marker you follow to monitor disease activity and response to treatment — not the confirmatory test.

Only after biochemical confirmation do you localise: MRI of the pituitary fossa to distinguish micro- from macroadenoma, formal perimetry and fundoscopy. The highest-yield bedside step to prove insidious change is to ask for old photographs or a driving licence.

For the coarse, changing appearance the lead differential is acromegaly; consider hypothyroidism (coarse features and macroglossia, but a high TSH and no acral enlargement) and simple obesity. For bilateral hand numbness, remember the CTS causes — endocrine (acromegaly, hypothyroidism), autoimmune (RA), metabolic (diabetes, CKD, amyloid), pregnancy and repetitive use — and distinguish them from a length-dependent glove-and-stocking neuropathy that starts in the toes. Beyond a sporadic adenoma, other causes of GH excess include MEN-1 (pituitary, parathyroid, pancreas), McCune-Albright syndrome and, rarely, ectopic GHRH from a carcinoid.

The viva: what examiners ask

Expect to be pushed through complications, investigation, classification and management. Have these ready:

• Complications to recite: diabetes (around 20%), hypertension with cardiomyopathy/LVH/heart failure, obstructive sleep apnoea and airway narrowing, colorectal polyps and cancer, compressive neuropathy (CTS) and spinal stenosis, proximal myopathy, arthropathy, hypercalciuria and renal stones, and hyperprolactinaemia with hypogonadism.
• Complications screen: HbA1c, ECG and transthoracic echo, colonoscopy for surveillance, polysomnography for OSA, serum calcium for MEN-1, and the full pituitary axis (prolactin, TFTs, gonadotrophins, 9 am cortisol or short Synacthen).
• Mass effect of a macroadenoma: bitemporal hemianopia, raised-ICP headache (worse on waking, coughing or straining), cavernous-sinus cranial nerve palsies and hypopituitarism.
• Management: trans-sphenoidal resection is first-line and definitive (trans-frontal for large suprasellar extension); medical options are a somatostatin analogue (octreotide, lanreotide), a dopamine agonist (cabergoline) or the GH-receptor antagonist pegvisomant; radiotherapy for residual disease. Treat each complication and arrange lifelong surveillance.
• If the patient is hypopituitary, replace hydrocortisone before thyroxine and before any surgery to avoid precipitating an adrenal crisis.
• The emergency: pituitary apoplexy — thunderclap headache, ophthalmoplegia and acute secondary adrenal insufficiency, often anticoagulation-precipitated. Check a 9 am cortisol and give hydrocortisone urgently.

Common pitfalls and how to score

• Do not stop at the presenting complication. Acromegaly is the unifying diagnosis behind CTS, OSA, secondary hypertension and glucose intolerance — link them out loud.
• Always offer to test visual fields, even when the headline is the hands. Forgetting the chiasm is a classic mark-loser.
• Answer the patient's real question. "Is my diabetes causing my numb hands?" — no: the thenar-sparing, lateral three-and-a-half-digit, Tinel-positive pattern localises to the carpal tunnel, and acromegalic CTS is the cause.
• Distinguish active from cured disease: sweaty palms, skin tags, headache and progressive soft-tissue change signal active disease, though bony and soft-tissue overgrowth persists even after biochemical cure.
• Frame prognosis correctly: excess mortality is driven mainly by cardiovascular disease and largely normalises with biochemical control — so treat early.