MELAS syndrome with rare manifestations misdiagnosed as vasculitis in the absence of lactic acidosis: A case report.

Introduction: The syndrome of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is one of the most common inherited mitochondrial disorders. Presentation of case: A 33- year-old male was admitted due to edema, urinary retention, and reduce urinary output. The medical history included a pigmentary retinopathy (PR) at age of 22 and uveitis at age of 30, which were both treated with prednisolone. At age of 32, unapparent bilateral sensorineural hearing loss (SNHL) and symmetric basal ganglia calcifications were observed in neurologic study, and received prednisolone for the diagnosis of migraine and undefined vasculitis. Also, he described a right transient ischemic stroke (TIA) in the past 4 months. His family history included a dead brother, who had nearly similar components. Physical exam on admission corresponded with parkinsonism. The status points to MELAS but the genetic test was not available. Additional tests were applied, excluding all other disorders. Lactate was normal in serum and CSF. Kidney tests revealed a nephrotic syndrome and glomerulopathy, and the biopsy showed a single hyalinized glomerulus, which most likely suggests focal segmental glomerulosclerosis (FSGS). Muscle biopsy showed ragged red fibers. Conclusion: Here, we report a challenging case of MELAS syndrome with rare manifestations including uveitis, PR, parkinsonism, and FSGS in the absence of lactic acidosis with unapparent muscle or hearing impairments. Since, clinicians might misdiagnose MELAS as vasculitis or other disorders due to its heterogeneous presentations, a proper investigations should guide the diagnosis of these conditions to reduce the delay of diagnosis and ineffective treatments.