Case of the Week

Background:

• Few studies have reported epileptic seizures as a complication of treated prolactin-producing macroadenoma. These have shown association of pituitary apoplexy (most commonly related to prolactinomas) under treatment or large tumors with extension into the suprasellar region, cavernous sinus, or medial temporal lobe.
• On MRI, evidence of hemosiderin deposition along the medial temporal lobe after intratumoral hemorrhage during medical treatment for pituitary macroadenoma can act as a trigger for seizure. Symptoms of weakness or paralysis, involving a part or all of the body soon after an episode of seizure (also known as Todd paralysis), make it the most common acute ischemic stroke mimic.

Clinical Presentation:

• Retro-orbital headache is the most common symptom of pituitary apoplexy, followed by vision loss. Seizures in patients with pituitary pathology are uncommon, however they are seen as a consequence of large prolactinomas, particularly those that are being treated. 
• Weakness or paralysis affecting a portion or the entire body following a seizure corresponds to the ictal topography, and presenting symptoms will localize to the area of brain where the seizure occurred, which is crucial in cases where the seizure was not witnessed.

Key Diagnostic Features:

• In pituitary apoplexy, MR imaging depicts a mass lesion as heterogeneous signal intensity with predominant hyperintensity on T1-weighted MR images and predominant hypointensity on T2-weighted images. T2*-weighted gradient-echo MR imaging helps in detecting intralesional bleeding with extension to subarachnoid (Sylvian fissure in our patient) or intraparenchymal compartments.
• On postcontrast images, there is peripheral rim enhancement in the acute phase and surrounding dura may show reactive thickening and enhancement.
• Regional vasogenic and cytotoxic edema occur after epileptic activity that reflects hemodynamic and metabolic changes, respectively. This makes them appear hyperintense on DWI, with no arterial distribution and with variable ADC values. They show high signal intensity on FLAIR and T2WI and low signal intensity on T1WI with cortical swelling. Hence, atypical distribution (temporo-occipital in our case) not pertaining to any arterial territory and involvement of the cortex only with T2 hypointense signal in the underlying white matter point towards postictal changes instead of stroke.  

Differential Diagnoses:

• Other conditions that can cause symptoms of headache, vomiting, visual disturbances, and hemodynamic instability or seizures: subarachnoid hemorrhage, infectious meningitis, cavernous sinus thrombosis, stroke. A history of preceding seizure with key imaging findings is an important differentiating factor.

Treatment:

• Based on the clinical, biochemical, and endocrine assessment, conservative management is considered that commonly includes steroid replacement therapy.
• In cases where there is severe visual loss or mental status deterioration, surgical management is considered.