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Pituitary adenoma — surgery and after
Every pituitary adenoma is first assessed hormonally: a prolactinoma is treated with cabergoline even when it is large and compresses the chiasm, whereas a non-functioning macroadenoma with a visual field defect, Cushing disease and acromegaly are operated on through a transsphenoidal approach.
Why it matters in the exam
Questions start with a patient with bitemporal hemianopia or an incidental sellar finding and test the correct order: first prolactin, IGF-1, morning cortisol, TSH and free T4, and visual field testing. A macroadenoma measures 10 mm or more. A slightly raised prolactin with a non-functioning macroadenoma can come from stalk compression (stalk effect) rather than a prolactinoma; a giant prolactinoma can show a "normal" prolactin because of the hook effect — so dilution is requested. Cavernous sinus involvement is graded on the Knosp scale from 0 to 4, and grades 3 and 4 predict incomplete removal.
After transsphenoidal surgery fluid balance and sodium must be followed: central diabetes insipidus appears in the first 1 to 2 days and usually resolves; a "triphasic response" comprises diabetes insipidus, then an SIADH phase with hyponatraemia around day 7, then permanent diabetes insipidus. Delayed hyponatraemia is a common cause of readmission. Cortisol must be checked and steroids given as needed, especially after Cushing surgery, where a sharp fall in cortisol indicates success. Other complications: CSF leak from the nose, carotid bleeding and visual injury. Pituitary apoplexy — sudden headache, visual loss and ocular nerve palsy — needs immediate hydrocortisone and assessment for urgent surgery when vision is affected.
Key points
- Hormonal work-up and visual fields before every decision.
- Prolactinoma — cabergoline, even when large.
- Non-functioning with compression, Cushing and acromegaly — transsphenoidal surgery.
- After surgery: early diabetes insipidus, SIADH around day 7.
- Apoplexy — immediate hydrocortisone.
Summary table
| Type | Presentation | First treatment | Note |
|---|---|---|---|
| Prolactinoma | Amenorrhoea, galactorrhoea, low libido | Cabergoline | Surgery only for failure or intolerance |
| Non-functioning macroadenoma | Bitemporal hemianopia, hormonal deficits | Transsphenoidal surgery | Mildly raised prolactin — stalk effect |
| Cushing disease | Central obesity, purple striae, hypertension | Transsphenoidal surgery | Fall in cortisol after surgery means success |
| Acromegaly | Enlarged hands and jaw, high IGF-1, no GH suppression on glucose load | Transsphenoidal surgery | Somatostatin analogues if it fails |
| Apoplexy | Sudden headache, vision, ocular nerves | Immediate hydrocortisone | Urgent surgery for visual loss |
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Sources
- Endocrine Society Clinical Practice Guideline: Pituitary Incidentaloma, 2011 — Evaluation and follow-up
- Pituitary Society consensus on the diagnosis and management of prolactin-secreting adenomas, 2023 — Medical and surgical therapy
- Congress of Neurological Surgeons guidelines on non-functioning pituitary adenomas, 2016 — Surgical resection and postoperative care
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.