Alternating Hemiplegia as A Major Symptom of Maple Syrup Urine Disease: Case Report

Abstract

The aim of the present study is to draw attention to the rare association of maple syrup urine disease and alternating hemiplegia. We describe a case report from medical record review. RFD, 3 years and 6 months, male, white, adopted 3 months before, had abrupt onset of paroxysmal motor events characterized by alternating hemiplegia, with a duration of 30 minutes, evolving with total and spontaneous recovery in up to 24 hours, totaling 28 in 6 months. There was no information on prior development and symptoms of the child currently presenting language and fine motor delay. The physical exam showed dimorphisms: absence of lip groove, thin upper lip, large eyes, thick eyebrows, blond and fine hair, brachydactyly, hypotrophy, hypotonia, hyperreflexia, and low weight. Magnetic resonance imaging of the brain was performed with spectroscopy revealing hypersignal of globus pallidus, subthalamic nuclei, thalamus, mesencephalon and dentate nuclei; restriction areas in the cerebellar hemisferes and hypersignal in subcortical white matter; branched chain amino acid spike. Analysis of urinary organic acids showed elevated levels of 3-hydroxybutyric acid, 2-hidroxisovaluric,2-hidroxi-3-metilvaluric, 2-hidroxisocaproic and 2- ketoisocapric acids, leucine, and isoleucine. The patient was diagnosed with MSUD and experienced resolution of neurological symptoms and milestones improvement after treatment with restriction of protein intake. MSUD has a worldwide incidence of 1: 185 000 live births and is not present in neonatal screening in our country, despite having treatment that alters the course of the disease. They can be divided into classical form and variants, that can vary according to the residual enzymatic activity. In the presenting case the lack of information of years previous to the adoption, associated with the rare atypical manifestation, lead to a difficulty in clinical suspicion and diagnosis. Despite the compatible laboratory and radiological diagnosis and good response to therapy for MSUD, gene sequencing was already requested for diagnostic confirmation of the subtype of the disease. There are only a few reports of the association between MSUD and alternating hemiplegia, making effective recognition and treatment a challenge. Therefore, it is necessary to approach the subject in order to improve these patient's morbidity and mortality, preventing the progress of neurological deficits.