Late Diagnosis of MELAS Can Lead to A Serious Brain Edema that Ultimately Requires Decompressive Craniectomy

Background: Mitochondrial myopathy, encephalopathy, lactic acidosis and recurrent stroke-like episodes (MELAS) is a rare, maternally inherited, neurodegenerative disease caused by mutations in the mitochondrial DNA. Early symptoms may include muscle weakness and pain, syncopes and seizures. The main pathophysiology is structural and functional abnormalities of mitochondrial DNA, various mutations affect mainly aerobic cellular metabolism at the level of electron transport chain. The clinical managament of patients is largely supportive.

Case: A 12 year-old-boy who had loss of conciousness one year ago which was treated like encephalitis, was having loss of consciousness spells with accompanying visual symptoms lasting 15-20 minutes since the last year. He presented to our pediatric intensive care unit with worsening episodes described as atonic seizures, inability to walk, vision loss and altered mental states for the last 10 days. He was unconsciousness and had stiff neck. Lumbar puncture was performed, no abnormal findings. His blood gas was normal. (No lactic asidosis.) Results of brain MR and CT imaging showed a lesion in the left occipital lobe with long T1, T2 signals,left shift and edema. On follow up, brain edema treatment was started and was commenced on ceftriaxon and acyclovir. All viral serology that could be cause of encephalitis and autoimmune encephalitis panel came back negative. Although he received antibiotheraphy,IVIG and pulse steroid treatment, his clinical findings and swelling/herniation were worsening so he was undergone decompressive craniectomy. The brain biopsy was determined non-specific encephalitis findings. MR angiography/venography was normal. The blood genetic test suggested a mutation of mt.3243A>T, so we got diagnosis of MELAS. After being treated with arginine and coenzyme Q10, the patient dramatically improved.

Conclusion: We should keep in mind that if the diagnosis and treatment was delayed, mitochondrial and metabolic disorders can cause serious brain edema which ultimately may require decompression surgery.