Chronic cough characteristics in CANVAS

Introduction: Chronic cough (CC) is often the presenting symptom of CANVAS; Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome, caused by biallelic repeat expansions in RFC1 gene. We investigated cough characteristics in CANVAS, compared to refractory chronic cough (RCC). Methods: Patients with neurologist-diagnosed CANVAS who had CC and patients with RCC without evidence of neuropathy were recruited. Symptoms were assessed with cough severity VAS, cough-specific Leicester Cough Questionnaire (LCQ) health status, and Cough Hypersensitivity Questionnaire (CHQ) for triggers. Objective 24hr cough frequency (CF) was measured with Leicester Cough Monitor and cough reflex sensitivity (CRS) with capsaicin challenge. Results: We recruited 53 patients with RCC and 8 patients with CANVAS. All patients with CANVAS had sensory neuropathy and abnormal nerve conduction studies, 7 had ataxia and vestibular areflexia. CC in CANVAS was refractory to asthma, reflux, or rhinitis treatments. Compared to RCC, patients with CANVAS had equal sex distribution and younger age of cough onset (median 33 vs 55 years), Table1. Patients with CANVAS had moderate-severe CF and QoL impact. CANVAS cough was associated with multiple triggers and heightened CRS, similar to RCC. Discussion: CC in CANVAS is refractory, impacts QoL, associated with cough reflex hypersensitivity, and presents at an earlier age compared to RCC. Studies to investigate the prevalence of CANVAS in patients with CC are needed.