Peripheral Nerve and Pituitary/Neuroendocrine Surgery - exam-focused guide
Peripheral Nerve and Pituitary/Neuroendocrine Surgery covers nerve injury and entrapment plus pituitary adenomas and neuroendocrine emergencies. The exam tests localization, timing of repair and hormonal management.
Core rules
- Peripheral nerve injury: neurapraxia recovers spontaneously; axonotmesis regenerates at about 1 mm/day; neurotmesis needs repair or grafting. Sharp injuries with transection are explored early; blunt injuries may be observed with EMG/NCS.
- Entrapment: carpal tunnel syndrome affects median nerve with nocturnal numbness; ulnar neuropathy at the elbow causes clawing and intrinsic weakness; peroneal palsy causes foot drop.
- Brachial plexus injury: root avulsion causes severe pain and no proximal recovery; evaluate with MRI and EMG. Timing of reconstruction depends on injury type.
- Pituitary adenomas: prolactinoma is treated with dopamine agonists; acromegaly with surgery, somatostatin analogues or radiotherapy; Cushing disease with transsphenoidal surgery.
- Pituitary apoplexy is an emergency with headache, visual loss, ophthalmoplegia and hypotension; give glucocorticoids and decompress urgently.
- Transsphenoidal surgery risks diabetes insipidus, SIADH, CSF leak and hypopituitarism.
Worked example: A 35-year-old has galactorrhea, amenorrhea and a prolactin of 3,000 ng/mL. This is a prolactinoma. Dopamine agonist therapy is first-line and usually shrinks the tumour; surgery is reserved for intolerance, resistance or apoplexy. A mildly raised prolactin may instead reflect stalk effect.
Traps: missing the prolactin hook effect in very high values; operating first on a prolactinoma; delaying steroids in apoplexy; confusing carpal tunnel with cervical radiculopathy; repairing a nerve too late without considering grafting.