Pituitary Disease — Written Clinical Reasoning

SAQ 1 — Pituitary Apoplexy Emergency Management (25 marks, 30 minutes)

Prompt: Outline your immediate and integrated management of this patient, including the emergency treatment, problem list, investigation interpretation, the decision on surgical versus conservative management, hormone replacement regimen with doses, and the long-term follow-up plan. Justify each decision with reference to evidence and guidelines. [1]

Model Answer

Immediate emergency management (5 marks): [1]

This patient has pituitary apoplexy — acute haemorrhage into a pituitary macroadenoma — presenting as a neuroendocrine emergency. He has two immediately life-threatening problems: presumptive adrenal crisis (ACTH deficiency causing hypotension and hyponatraemia) and progressive visual loss from chiasm and cavernous sinus compression. [1]

1. Empirical intravenous hydrocortisone immediately. Per the UK guidelines for pituitary apoplexy (Rajasekaran 2011, PMID 21044119), empirical steroid therapy is indicated for patients with haemodynamic instability, altered consciousness, reduced visual acuity, or severe visual field defects. This patient meets all four criteria. Give hydrocortisone 100 to 200 mg intravenous bolus, followed by either 50 to 100 mg intramuscularly every 6 hours or 2 to 4 mg per hour continuous intravenous infusion. This treats the presumptive adrenal crisis (cortisol of 95 nmol/L confirms ACTH deficiency) and reduces peritumoural oedema. Do NOT wait for cortisol results before treating. [1]

2. Fluid resuscitation — intravenous normal saline to correct hypotension and hyponatraemia. Monitor input and output, central venous pressure if unstable. [1]

3. Close neurological monitoring — GCS hourly, visual acuity and fields serially (at least daily), cranial nerve examination. Notify the neurosurgical and endocrine teams immediately. [1]

4. Airway and breathing — the drowsy patient may deteriorate; have a low threshold for ICU admission. [1]

Problem list (4 marks): [1]

1. Pituitary apoplexy — acute haemorrhage into a pituitary macroadenoma (medical and potentially surgical emergency)
2. Secondary adrenal insufficiency (ACTH deficiency) — cortisol 95 nmol/L, hypotension, hyponatraemia
3. Central hypothyroidism — free T4 8 pmol/L with inappropriately normal TSH
4. Right third cranial nerve palsy and bitemporal hemianopia — cavernous sinus and chiasm compression
5. Hyponatraemia (sodium 128 mmol/L) — from cortisol deficiency and possibly SIADH from the acute event
6. Warfarin therapy — relative contributor to the haemorrhage; reverse with vitamin K and prothrombinex in consultation with haematology
7. Atrial fibrillation and hypertension — comorbidities requiring ongoing management
8. Likely non-functioning macroadenoma (prolactin 220 mU/L is a stalk effect, not a prolactinoma) [1]

Investigation interpretation (4 marks): [1]

• Cortisol 95 nmol/L: Diagnostic of ACTH deficiency in the acute setting. A 9 AM cortisol below 100 nmol/L in a patient with pituitary disease does not require dynamic confirmation. This explains the hypotension, drowsiness, and hyponatraemia.
• Free T4 8 pmol/L with TSH 0.8 mU/L: Central hypothyroidism — the free T4 is low with an inappropriately normal TSH (in primary hypothyroidism the TSH would be elevated). This confirms hypothalamic-pituitary axis dysfunction.
• Prolactin 220 mU/L: This is only mildly elevated and is disproportionate to the 2.5 cm tumour — it is the STALK EFFECT (compression of the pituitary stalk removing tonic dopamine inhibition), not a macroprolactinoma. A true macroprolactinoma of this size would have a prolactin above 5000 mU/L. This is a non-functioning adenoma — the treatment is surgery if needed, not cabergoline.
• Sodium 128 mmol/L: Due to cortisol deficiency (cortisol is needed for free water clearance; deficiency causes increased ADH secretion). May also have a component of SIADH from the acute neurological event. Will correct with hydrocortisone replacement.
• CT and MRI: Confirm a pituitary macroadenoma with acute haemorrhage and infarction — the classic radiological appearance of apoplexy. [1]

Surgical versus conservative management decision (4 marks): [1]

Per the UK guidelines, the decision is made in a pituitary multidisciplinary team (endocrinology, neurosurgery, ophthalmology). The indications for surgical decompression (transsphenoidal) within 1 to 2 weeks are:

• Severely reduced visual acuity
• Severe and persistent visual field defects
• Deteriorating level of consciousness
• Worsening neurological symptoms [1]

This patient has a right CN III palsy, a bitemporal hemianopia, and is drowsy — he meets criteria for surgical consideration. The decision would be: urgent neurosurgical referral for transsphenoidal decompression, performed after medical stabilisation with hydrocortisone and fluids. If his visual acuity or consciousness deteriorates, surgery would be expedited. [1]

Conservative management (hydrocortisone, fluids, and observation without surgery) is appropriate for patients with no visual compromise or with improving symptoms. The evidence suggests that both approaches can yield good outcomes, but surgery offers faster visual recovery for patients with significant visual deficit. [1]

Hormone replacement regimen (4 marks): [1]

1. Hydrocortisone FIRST — 100 mg IV stat, then 50 mg IV every 6 hours or continuous infusion. Once stable, convert to oral hydrocortisone 10 mg morning, 5 mg noon, 5 mg at 4 PM (total 20 mg daily). Provide patient education, MedicAlert bracelet, and emergency hydrocortisone injection kit with sick day rules. [1]

2. Levothyroxine AFTER cortisol is established — start levothyroxine 1.6 microgram per kg per day (approximately 100 to 125 microgram daily) once hydrocortisone is commenced. NEVER start levothyroxine before hydrocortisone — the increased T4 accelerates cortisol clearance and precipitates adrenal crisis. Monitor free T4 (NOT TSH — TSH is unreliable in central hypothyroidism) and titrate to mid-normal free T4. [1]

3. Sex hormone replacement — once stable, assess gonadal axis. This man would need testosterone replacement if LH/FSH and testosterone are low. [1]

4. GH — assess for GH deficiency once stable; may benefit from somatropin replacement if confirmed deficient and no contraindications. [1]

5. Desmopressin — monitor for diabetes insipidus (especially after surgery). If polyuria develops, start desmopressin 100 to 200 microgram orally two to three times daily. [1]

Long-term follow-up (4 marks): [1]

• Lifelong endocrine follow-up — most patients develop permanent hypopituitarism after apoplexy and require ongoing multi-axis replacement.
• Visual fields and acuity — formal perimetry at 3 months, then annually, or sooner if symptomatic.
• MRI surveillance — at 3 months post-event, then annually for the first 3 years to monitor for residual or recurrent tumour.
• Pituitary panel — monitor cortisol (hydrocortisone adequacy), free T4, testosterone, IGF-1 at each visit. Adjust replacement as needed.
• Patient education — steroid card, MedicAlert, sick day rules, emergency hydrocortisone kit. Ensure family and GP know the sick day rules.
• Address cardiovascular risk — this patient has hypertension and atrial fibrillation; manage anticoagulation carefully (the apoplexy was potentially precipitated by warfarin). [1]

SAQ 2 — Acromegaly Workup and Management Plan (15 marks, 20 minutes)

Prompt: A 49-year-old man is referred by his GP for assessment of progressive enlargement of his hands and feet over 2 years. His wife has noticed his jaw is more prominent and he snores heavily. He has recently been diagnosed with type 2 diabetes and hypertension. On examination he has frontal bossing, prognathism with interdental spaces, large sweaty hands, multiple skin tags, and blood pressure 160/96. Outline the diagnostic workup, the management plan, and the surveillance strategy. Justify with evidence. [1]

Model Answer

Diagnostic workup (5 marks): [1]

The clinical features are highly suggestive of acromegaly. The diagnostic pathway per the Endocrine Society acromegaly guideline (Katznelson 2014, PMID 25356808) is: [1]

1. Serum IGF-1 (age- and sex-matched) as screening. IGF-1 is the integrative marker of GH action — it is stable and reflects average GH exposure. A normal IGF-1 excludes acromegaly. I expect it to be elevated. [1]

2. Oral glucose tolerance test with GH measurement (confirmation). If IGF-1 is elevated, give 75 g oral glucose and measure GH at 0, 30, 60, 90, and 120 minutes. Failure of GH to suppress below 1.0 microgram per litre (0.4 on modern sensitive assays) confirms acromegaly. This patient would be expected to fail suppression. [1]

3. MRI pituitary with contrast to localise the somatotroph adenoma. [1]

4. Full anterior pituitary panel — cortisol, TSH, free T4, LH, FSH, testosterone, prolactin — to assess for co-secretion (e.g., prolactin in a mammosomatotroph adenoma) or hypopituitarism from mass effect. [1]

5. Visual fields (Humphrey perimetry) — if the tumour abuts the chiasm. [1]

6. Echocardiogram — screen for acromegalic cardiomyopathy (concentric LVH, diastolic dysfunction). [1]

7. Sleep study — screen for obstructive sleep apnoea (affects up to 70% of acromegaly patients; an independent cause of mortality). [1]

8. Colonoscopy — acromegaly increases colonic polyp and colon cancer risk; colonoscopy is mandatory at diagnosis. [1]

Management plan (6 marks): [1]

1. Transsphenoidal surgery first-line. This is the gold standard. An experienced pituitary surgeon achieves biochemical remission in 75 to 95% of microadenomas and 40 to 70% of macroadenomas. Cure is defined as normal IGF-1 and GH below 1.0 microgram per litre with OGTT nadir below 0.4 (modern assay). [1]

2. Medical therapy if not cured. If surgery does not achieve biochemical remission (likely if this is a macroadenoma with cavernous sinus invasion), start a first-generation somatostatin analogue: octreotide LAR 20 to 30 mg IM every 4 weeks, or lanreotide autogel 90 to 120 mg SC every 4 weeks. These normalise IGF-1 in 50 to 60% and shrink residual tumour in 40 to 60%. [1]

3. Escalate if resistant. If IGF-1 is not controlled on first-generation SSA, escalate to pasireotide LAR (PAOLA trial, PMID 25260838, showed superior efficacy but with hyperglycaemia risk) or pegvisomant (GH receptor antagonist; Trainer trial, PMID 10770982, normalised IGF-1 in 89%). Monitor LFTs on pegvisomant. [1]

4. Treat comorbidities aggressively. Control type 2 diabetes (consider metformin first-line; GH excess causes insulin resistance, which improves with biochemical control), hypertension (ACE inhibitor or ARB), and dyslipidaemia. [1]

5. CPAP for obstructive sleep apnoea — mandatory pre-operatively to reduce anaesthetic risk and long-term cardiovascular mortality. [1]

Surveillance strategy (4 marks): [1]

• IGF-1 every 3 to 6 months — aim for normal IGF-1 and GH below 1.0 microgram per litre. Biochemical control restores mortality to population norms.
• Annual MRI for the first 3 years, then less frequently if stable.
• Annual anterior pituitary panel — surgery and medical therapy may cause or unmask hypopituitarism.
• Colonoscopy at 3 to 5 years (or sooner if polyps found at baseline).
• Echocardiogram every 2 to 3 years to monitor cardiomyopathy.
• Annual sleep study review.
• Visual fields annually if the tumour abuts the chiasm.
• Patient education about the chronic nature of the disease, the importance of adherence to medical therapy, and the role of biochemical control in restoring life expectancy. [1]