Disseminated Subpial Demyelination Presenting as Respiratory Stridor

Abstract

A 61‐year‐old female with long‐standing bipolar disorder presented with recurrent episodes of laryngeal stridor occurring over 2 years. Her stridor was worse while lying supine, and examination of her vocal cords show paradoxical movement. MRI showed scattered diffuse white matter lesions in the cerebral hemispheres without brainstem involvement. Her final episode of stridor was fatal, and an autopsy was performed revealing no abnormalities of laryngeal structures. Examination of her brain showed diffuse anoxic encephalopathy with acute and remote infarctions in or adjacent to bilateral caudate nuclei. There were numerous chronic demyelinating lesions, demonstrated by LFB/PAS and Bielschowsky stains, located in the optic chiasm, cerebellum, midbrain, pons and medulla. Many of these lesions were localized to the subpial parenchyma, a finding which was most evident in the pons and medulla. Involvement of the dorsal motor nucleus and other fibers contributing to the formation cranial nerve X as it exits the medulla was also noted and may have contributed to her stridor. The pattern of demyelination demonstrated in this case has been referred to as disseminated subpial demyelination, which has only been reported twice in the literature in the absence of classic patterns of demyelination, and it may represent an unusual phenotype of multiple sclerosis.