Subarachnoid Haemorrhage with Pituitary Adenoma

Pituitary apoplexy is an uncommon syndrome typically resulting from ischaemic or haemorrhagic necrosis of an existing pituitary adenoma. Patients classically present with sudden-onset severe headache, reduced consciousness, and meningeal irritation. For this reason, the clinical picture is frequently mistaken as being caused by aneurysmal subarachnoid haemorrhage (SAH). It is necessary to distinguish preoperatively between pituitary apoplexy and SAH as there are reports of inappropriate craniotomy being performed with a view to clipping nonexistent aneurysms. Importantly, transsphenoidal excision of a pituitary adenoma risks rupture of an unidentified intracranial aneurysm. This is particularly significant given the established association between pituitary adenoma and development of intracranial aneurysms. This chapter reviews the epidemiology and pathophysiology underlying the relationship between pituitary tumours, intracranial aneurysms, and SAH. It also makes evidence-based recommendations for the investigation of patients with suspected pituitary apoplexy to identify associated conditions preoperatively and manage the risk of iatrogenic aneurysm rupture.