LAUSR

A brainstem syndrome is recognizable in patients presenting with a combination of visual disturbances, incoordination, gait problems, speech and swallowing difficulties, and new-onset sleep symptomatology. Brainstem disorders of subacute onset (onset and progression with accumulation of disabling deficits in 6–12 weeks) are generally of autoimmune, infectious, inflammatory, or infiltrative neoplastic cause. An autoimmune or infectious brainstem disorder may be referred to as brainstem encephalitis or rhombencephalitis. We describe a patient with paraneoplastic autoimmune rhombencephalitis, in whom diagnostic clues included the following: diverse visual and sleep symptoms, trismus, and choking in the history; see-saw nystagmus, opsoclonus, dysarthria, jaw dystonia, and episodic laryngospasm on examination; subtle but longitudinal and nonenhancing T2 MRI abnormalities in the brainstem and upper cervical cord; and oligoclonal bands in the CSF. His movement disorder–specific neural IgG profile revealed ANNA-2 (anti-Ri) and KLHL-11-IgG. Both are biomarkers of paraneoplastic brainstem encephalitis. KLCHL-11-IgG has been reported to accompany germ cell tumors, which was found in a solitary metastasis to the left inguinal lymph node in our patient, along with an atrophic left testis. Multidisciplinary treatment (autoimmune neurology, sleep medicine, ophthalmology, and physiatry) led to significant clinical improvements. This case provides a framework for the evaluation of patients with subacute-onset brainstem syndromes and the investigation and management of those with paraneoplastic and other autoimmune diseases.