Investigation of Toxic Metabolic Encephalopathy in Adult Polyglucosan Body Disease & Other Genetic Leukoencephalopathies
William Roberts1, Vinit Parekh2, Brett Irving2, Jennifer Orthmann-Murphy1
1Hospital of the University of Pennsylvania, Department of Neurology, 2Pennsylvania Hospital, Department of Medicine
Objective:
This case report explores the complexities in diagnosis and management of patients with Adult Polyglucosan Body Disease (APBD) and other genetic leukoencephalopathies, particularly within the context of toxic metabolic encephalopathy (TME).
Background:
APBD is a type IV glycogen storage disease caused by a glycogen branching enzyme deficiency, leading to intracellular polyglucosan body aggregation throughout the nervous system. It presents in adulthood with progressive cognitive decline, spastic paraplegia, gait instability, and neurogenic bladder in the setting of white matter lesions. With only approximately 200 cases reported worldwide, the typical clinical course is not well understood, and the presentation of toxic-metabolic derangements in this population remains poorly characterized.
Results:
We present a 62-year-old male with APBD who presented with progressive confusion and dysarthria initially concerning for stroke vs. primary APBD manifestation. Neuroimaging demonstrated stable white matter changes and no acute intracranial process. Labs were significant for acute kidney injury in the setting of a urinary tract infection and hydronephrosis, managed with nephrostomy tube placement and antibiotics. Despite improvement in his metabolic derangements and antimicrobial therapy, he continued to display impaired mental status. Additional work-up, including a lumbar puncture and EEG, was unrevealing. He began to demonstrate slow recovery to his baseline cognition, prolonging his hospitalization to 17 days.
Conclusions:
The clinical course of APBD and similar inherited white matter disorders remains poorly understood, warranting further study to distinguish primary disease manifestations from secondary TME. These patients have limited neurological reserve, and cognitive recovery may lag despite clinical improvement after non-neurologic insults. This case highlights the uncertainty surrounding the expected nadir and recovery in TME and the difficulty in discerning contribution of underlying APBD. With no disease-modifying therapies available, management is largely a multidisciplinary supportive and preventative approach. Improved understanding of APBD’s natural course and secondary complications is essential to optimizing care for leukodystrophies.
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