To report clinical case of pituitary apoplexy (PA) mimicking meningoencephalitis (ME) in order to aid early diagnosis and treatment of PA.

PA is a rare but potentially life-threatening condition which may require urgent surgical intervention. The most common clinical manifestations consist of headache, vision impairment, ophthalmoplegia, and hypopituitarism. Other less common findings include meningism and CSF pleocytosis, which may lead to a misdiagnosis like meningoencephalitis, which can cause permanent neurologic sequelae or even death due to delayed treatment.

We report a case that was eventually diagnosed with PA, but had been misdiagnosed as a ME based on clinical manifestations and CSF profile. We also conducted a literature review of other similar published cases and summarized their clinical features.

Headache is the most common symptom, which presents in 100% cases. Hypopituitarism exists in 94.4% cases, among which panhypopituitariam was noted in 38.9% cases. The sensitivity of MRI for detecting PA is 94.7%, much higher than that of CT which is only 31.6%. Neutrophil predominant pleocytosis was present in all cases with neutrophil percentage range from 73% to 98%.  CSF leukocyte count was less than 1000/ul in 86% cases. CSF erythrocyte existed in 92.9% cases with erythrocyte count range from 15 to 2030/ul. Elevated CSF protein was present in all cases with range from 69.8 to 239 mg/dl. CSF glucose level varied from 12 to 136 mg/dl, however, the level was greater than 40 mg/dl in 73% cases.

MRI is the most sensitive tool for preoperative diagnosis of PA.  CSF pleocytosis is always neutrophil predominant in this case series, which is similar with bacterial ME and could be used to rule out viral or fungal ME. On the other hand, CSF leukocyte amount is usually less than 1000/ul and glucose is usually not decreased, which are possible distinguishing features from bacterial ME.