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Adult onset MELAS Syndrome Presenting as A Mimic of Herpes Simplex Encephalitis

Wan-Ting Chen1, Yung-Shuan Lin1, Yen-Feng Wang1

  • 1Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.

Acta Neurologica Taiwanica
|December 24, 2019
PubMed
Abstract

Insights

Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) can present in older adults, mimicking infections like herpes simplex encephalitis (HSE). Early diagnosis and avoiding mitochondrial toxins are crucial for managing this rare condition.

Area of Science:

  • Neurology
  • Genetics
  • Mitochondrial Diseases

Background:

  • Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is often diagnosed in younger individuals.
  • In older adults, MELAS can present with symptoms mimicking infectious encephalopathies, such as herpes simplex encephalitis (HSE).

Observation:

  • A 52-year-old woman with diabetes and end-stage renal disease presented with acute fever, delirium, and epilepsy.
  • Initial symptoms mimicked HSE, but persistent elevated cerebrospinal fluid lactate and mitochondrial DNA analysis confirmed MELAS.

Findings:

  • The patient had a point mutation at nucleotide 3243 in her mitochondrial DNA.
  • Clinical presentation and imaging in adult MELAS cases can be highly variable, resembling HSE.

Implications:

  • Antiviral therapy is recommended for suspected HSE until MELAS is definitively diagnosed.
  • Infection and certain medications (e.g., metformin) may precipitate MELAS in susceptible individuals.
  • Clinicians should exercise caution and avoid potentially mitochondrial-toxic drugs in patients with suspected MELAS.

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