(Kiosk 4) Novel Variant of Acute Motor and Sensory Axonal Neuropathy (AMSAN) with Bulbar Involvement

Case Diagnosis: Novel variant of acute motor and sensory axonal neuropathy (AMSAN) with bulbar involvement

Case Description or Program Description: 34-year-old female with a history of alcohol abuse presented to the emergency department with worsening lower extremity weakness and paresthesia with recurrent falls for the last four weeks. Prior to her presentation, patient recalled seven days of severe nausea and diarrhea. In an extensive inpatient workup, was diagnosed Guillain Barre Syndrome (GBS) with thiamine and folate deficiency. She received 1 round of IVIG and vitamin supplementation with initial stabilization of symptoms. The patient was discharged to acute inpatient rehabilitation. During her stay, she suffered further decline including total hearing loss and progressive weakness prompting transfer back to acute care for additional work-up and treatment. She received a second dose of IVIG, resulting in clinical stabilization. Electrodiagnostic testing revealed motor and sensory axonal damage with increased spontaneous motor activity in all extremities. She was diagnosed with severe acute motor and sensory axonal neuropathy (AMSAN) with variance affecting cranial nerve eight.

Setting: Inpatient Rehabilitation facility

Assessment/Results: Long-term care was set up prior to discharge in preparation for her prolonged recovery.

Discussion (relevance): This case illustrates an atypical, and sparsely documented, type of GBS. AMSAN involves axonal, rather than myelin, damage via an antibody/compliment mediated response. Axonal-targeted GBS is frequently observed in China, Japan, and Mexico, but only makes up 5 to 10 percent of GBS cases in the United States. AMSAN is primarily preceded by Campylobacter jejuni infections. AMSAN is usually more severe with a poorer prognosis for recovery. Thus, it is paramount to consider timely electrodiagnostic testing in the setting of progressive GBS, to assure accurate diagnosis and appropriate management.

Conclusions: This case demonstrates an atypical presentation of AMSAN with vestibulocochlear involvement. Axonal variants of GBS should be considered in cases of unexpected plateau or decline given implications for prognosis and rehabilitation planning.