November 10, 2014
Superficial siderosis is an uncommon disorder affecting the central nervous system. Due to its low prevalence, superficial siderosis often goes undetected at initial evaluation and patients are commonly misdiagnosed with a neurodegenerative process. In this disorder, hemosiderin, a breakdown product of hemoglobin, accumulates in the subpial layers of the brain resulting in parenchymal damage. Patients will often present with a sensorineural hearing loss and progressive cerebellar ataxia, which patients frequently cite as the most troubling symptom. Superficial siderosis is frequently caused from remote trauma or hemorrhage, often subarachnoid, and can be subclinical. Ferritin is thought to be crucial in the conversion of hemoglobin to hemosiderin. Ferritin-containing microglia and associated Bergmann glia are present in high concentrations in the cerebellar molecular layer, which may provide clues into the preferential deposition of hemosiderin around the cerebellar cortex. As the clinical diagnosis is challenging, MRI imaging is often the first clue to such a diagnosis.
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Submitted by: James Addington, MD, Resident Physician, Department of Neurology University of Virginia.
Dr. Addington is a member of the Neurology Resident and Fellow Editorial team.