1117 - Methylmalonic Acidemia with a Metabolic Stroke: A Pediatric Case Report

Thursday, February 22, 2024

5:00 PM – 6:30 PM EDT

Presenting Author(s)

Madeline C. Miller, MD

Resident Physician
Shirley Ryan Ability Lab, Nothwestern McGaw
Chicago, Illinois, United States

Co-Author(s)

GR

Gadi Revivo, DO

Attending Physician
Shirley Ryan Ability Lab, Nothwestern McGaw
Chicago, Illinois, United States

Presenting Author(s)

SW

Sean Weber, DO

Resident Physician
Shirley Ryan AbilityLab/Northwestern University
Illinois, Illinois, United States

Case Diagnosis: Methylmalonic acidemia (MMA) with metabolic stroke

Case Description: The patient was a previously healthy, typically developing 5-year-old girl who recently immigrated to the United States (U.S.). She presented to a children’s hospital with fever, decreased oral intake, emesis, and tachypnea. She was initially diagnosed with strep throat and COVID-19. Soon after, she developed encephalopathy with posturing. Work-up revealed severe metabolic acidosis (pH 6.9, bicarb 3) and elevated methylmalonic acid, leading to the diagnosis of MMA. MRI revealed symmetric diffusion restriction in bilateral globi pallidi, compatible with a metabolic stroke. EEG revealed no seizure activity. Treatment included tube feeds with low protein content and levocarnitine. At admission to the inpatient rehab facility (IRF), the patient had hypotonia, most notably in her neck and trunk, orofacial dyskinesia, dysphagia, and was largely non-verbal.

Discussions: MMA is rare, and severe complications are rarely seen in the US. This patient, born outside the US, had a limited newborn screening that did not include MMA. Decompensation in MMA can be triggered by systemic illness, such as the bacterial/viral illness seen in this patient. Consequences of severe metabolic crises include neurologic manifestations such as metabolic strokes (with the globi pallidi as a typical location), seizures, or developmental delay. Acute medical management for MMA is fairly well outlined, but patients may have rehabilitation needs specific to neurologic sequelae. For this patient, rehabilitation goals included improving communication and mobility, and navigating activities of daily living, with the use of technology and adaptive devices, while also optimizing medical management aimed at avoiding repeated decompensation and further neurological insult.

Conclusions: MMA and severe neurologic manifestations are rare, so little is reported regarding impairments and rehabilitation specific management. MMA patients require unique medical and dietary management which must be balanced with the management of stroke sequelae including tone issues, swallow concerns, communication and cognitive deficits.