A Tree Leading to the Root Cause of Encephalopathy

1University of Maryland School of Medicine, Baltimore, MD

Meeting: Hospital Medicine 2011, May 10-13, Dallas, Texas.

Abstract number: 291

Case Presentation:

A 50‐year‐old woman presented with acute‐onset confusion and seizure‐like episodes. She had experienced recent fatigue, generalized weakness, dyspnea on exertion, and ataxia for several days. She did not drink alcohol or use illicit drugs. History was notable for childhood‐onset hearing impairment, bilateral ptosis requiring surgery, and nonischemic cardiomyopathy. Family history included a mother with heart failure, a sister with congenital hearing impairment and early‐onset heart failure and multiple maternal cousins with deafness. The patient was confused and speaking in nonsensical fragments. She had a disconjugate gaze, widened alae nasale, ptosis, and bilateral hearing aids. She had left‐sided neglect, left‐sided weakness, and dysarthria. She had an S3 gallop and jugular venous pressure, estimated at 10 cm H2O; she had bibasilar crackles. Laboratory data revealed a serum bicarbonate of 9 mmol/L, an anion gap of 19, and a lactic acid level of 4 mmol/L that remained elevated throughout the hospital course. A magnetic resonance image of the brain demonstrated scattered subacute infarcts with atypical rapidly evolving changes on repeat imaging. She had low voltage on electrocardiogram. Echocardiogram revealed an ejection fraction of 30%, left atrial enlargement, normal ventricular wall thickness, and a dilated inferior vena cava suggestive of increased right atrial pressures. Given the patient's presentation with encephalopathy, systolic heart failure, persistent lactic acidosis, and a family tree suggestive of a maternal inheritance pattern of deafness and early‐onset cardiomyopathy, the team was suspicious for an inherited mitochondrial disorder. A muscle biopsy was obtained, which demonstrated variable fiber diameters, atrophic “ragged‐red” fibers, characteristic staining, and morphologically abnormal mitochondria with “parking‐lot” inclusions. The patient was diagnosed with mito‐chondrial myopathy, encephalopathy, lactic acidosis, and stroke‐like episodes (MELAS) syndrome.


Encephalo‐pathy is a problem frequently encountered by hospitalists. Although most etiologies can be rapidly diagnosed with history, physical examination, and laboratory/radiologic evaluation, some etiologies are not readily apparent. This case illustrates the importance of considering inherited genetic causes of encephalopathy in the setting of multiorgan dysfunction without an obvious etiology. MELAS syndrome is a rare genetic disorder that results most frequently from mutations in maternal mitochondrial DNA and has variable phenotypic expression. Mitochondrial disorders commonly present with dysfunction of multiple organ systems that are reliant on aerobic respiration, such as the heart and brain, as was the case in this patient.


This case highlights the importance of considering inherited metabolic disorders when evaluating encephalopathy and multiorgan dysfunction in the hospitalized patient without an obvious etiology.


R. Habicht ‐ none; E. Weld ‐ none

To cite this abstract:

Habicht R, Weld E. A Tree Leading to the Root Cause of Encephalopathy. Abstract published at Hospital Medicine 2011, May 10-13, Dallas, Texas. Abstract 291. Journal of Hospital Medicine. 2011; 6 (suppl 2). https://www.shmabstracts.com/abstract/a-tree-leading-to-the-root-cause-of-encephalopathy/. Accessed April 10, 2020.

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