Pituitary apoplexy: Pitfalls in diagnosis

Headache is a common presenting complaint in the emergency department. A rare cause is pituitary apoplexy - a complication of pituitary adenoma consisting of hemorrhage or infarction of the primary tumor accounting for approximately 1 % of headaches. A 44 -year -old female presented with intractable headache, nausea, photophobia and later - signs of meningeal irritation. Initial imaging demonstrated no mass or hemorrhage, labs showed only leukocytosis and elevated CRP. Patient was started on empiric acyclovir and methylprednisolone. CSF analysis was negative for meningitis, thus MRI of the brain was performed which demonstrated a 2.5 cm suprasellar mass. Initial Pituitary hormone evaluation demonstrated low prolactin, normal TSH and low ACTH thought to be due to steroid use. Repeat laboratory evaluation demonstrated hypopituitarism. Patient underwent resection of the adenoma with pathology consistent with pituitary apoplexy. We highlight the need for careful evaluation of patients presenting with headache and signs of meningeal irritation given 16 % prevalence of pituitary adenoma. CT of the head may not always demonstrate acute infarction, with MRI of the brain remaining the most sensitive imaging modality. Given the common use of methylprednisolone for headache, a pitfall in the diagnosis of pituitary apoplexy includes proper assessment of a pituitary panel prior to initiation of steroids.