Angiographically occult micro-arteriovenous malformation as a rare cause of recurrent Intracerebral hemorrhage (I2-2A)

Abstract

Objective: To report a case of angiographically occult, recurrent non-hypertensive lobar intracerebral hemorrhage (ICH) due to a micro arteriovenous malformation (micro-AVM). Introduction: Micro-AVM is abnormal connection between arteries and veins, characterized by nidus ≤ 1 centimeter diameter. Conventional angiogram is the gold standard procedure for diagnosis of AVMs. Although not all micro-AVMs can be detected on conventional angiogram, they represent about 8-10[percnt] of surgically treated AVMs. The risk of intracranial hemorrhage with such micro-AVMs is unknown. Case Report: We present a 50 year old woman who presented with acute onset left sided weakness. Her vitals including blood pressure were noted to be normal on presentation. CT head revealed a right parietal lobar ICH. MRI of the brain did not show evidence of microhemorrhages, amyloid angiopathy or dural venous fistula. Conventional cerebral angiogram was negative for any aneurysms or AVM. Etiology of the hemorrhage was deemed to be cryptogenic. A month later she improved to modified Rankin Scale (mRS) of 0. Three months later, she presented again with left sided weakness. CT of the head, at that time, revealed an acute parietal hematoma in the same location as prior. She underwent hematoma evacuation and a diagnostic biopsy. Biopsy showed evidence of abnormal vascular wall, suggestive of vascular malformation. A year after initial ICH, repeat diagnostic angiogram was again negative for any AVM or vascular malformation. Discussion and Conclusion: Diagnosis of micro-AVM requires high index of clinical suspicion in young patients with atypical hemorrhage locations. Conventional angiogram during the initial presentation and at three months follow-up may fail to reveal source of Intracerebral hemorrhage. We propose that limited resources should not be exhausted for a follow-up angiogram especially if it was inconclusive during the initial evaluation and early biopsy should be considered instead.

Disclosure: Dr. Patel has nothing to disclose. Dr. Tunguturi has nothing to disclose. Dr. Puri has nothing to disclose. Dr. Moonis has nothing to disclose.