Brain Herniation Due To Mitochondrial Encephalomyopathy, Lactic Acidosis, Stroke Like Events (MELAS) With 3256 Mutation Responsive To Decompressive Craniotomy (P6.257)

OBJECTIVE: To describe the early warning signs of clinical exacerbation and possible treatment in acute phase of stroke-like episodes (SLE) via a brain herniation case due to MELAS. BACKGROUND: MELAS is a maternally inherited multisystem mitochondrial disorder affecting children and young adults. SLE are frequently associated with aphasia, hemianopsia, hemiparesis, hemineglect and hemiaesthesia epileptic seizures, ataxia, migraine-like headache, visual impairment, amnesia, cognitive impairment, psychosis, hallucinations, confessional state, or coma. However, brain herniation is rarely reported and the characters in acute SLE are less well defined. METHODS: We report a case in which a 18 year old female was diagnosed with MELAS by confirming T3256C mutation and developed two SLE. RESULTS: The early signs of deterioration included increased lactic acid and severe headache refractory to narcotics. Patient developed left hemiparesis and left homonymous hemianopsia gradually with right occipital lesion in 2010. Her second SLE was similar but on the opposite side in 2012. Patient had normal MRI T1, T2, FLAIR, DWI and ADC findings on the second day of SLE although DWI and FLAIR detected the abnormalities on the third days of SLE onset. The MRI changes were prominent two weeks after the onset. Compared with the radiological abnormalities of ischemic stroke, CT and MRI brain showed prominent cortical edema. Symptoms were improved after steroid, anticonvulsants and symptomatic treatments. Patient had neurological decline after the steroid was discontinued and CT head revealed significant brain herniation due to expansion of left sided lesion. Emergent decompressive craniotomy was performed. The clinical symptoms and lactic acid level were rapidly improved. Patient almost returned to her baseline during the fellow up. CONCLUSIONS: In our MELAS case, decompessive craniotomy is life saving for brain herniation due to SLE. Headache refractory to narcotics and increased lactic acid level are early warning signs of acute SLE since MRI can be normal. Steriod might be indicated for acute treatment of cortical edema. Disclosure: Dr. Cui has nothing to disclose. Dr. Schwendimann has received research support from Lundbeck.