Prospective Dysphagia Assessment in Adult Patients With Nephropathic Cystinosis

Myopathy and dysphagia are common manifestations of nephropathic cystinosis, a rare autosomal recessive lysosomal storage disorder. We previously demonstrated that both the oral and pharyngeal phases of swallowing are affected and impact function and quality of life in patients. To better understand and characterize swallowing impairment, we evaluated patients with nephropathic cystinosis experiencing dysphagia and myopathy.

We prospectively evaluated patients who had participated in a prior clinical trial readiness study of myopathy and dysphagia, using functional outcomes and video fluoroscopic swallowing studies.

Eight patients underwent functional and swallowing assessments. Oral and pharyngeal stages of swallowing were affected in all subjects. There was an improvement in oral stage dysphagia (Visit 3 8 [3:9]; Visit 4 5 [1:5]) between Visits 3 and 4 median of 1090 days (IQR [921:1288]) while pharyngeal stage dysphagia Modified Barium Swallow Impairment Profile scores stayed unchanged in the same amount of time. There was also improvement in M. D. Anderson Dysphagia Inventory (MDADI) scores (MDADI-C Visit 3 73 [62:87], Visit 4 96 [76:99]; MDADI-F Visit 3 18 [17:21], Visit 4 25 [23:25]), indicating a higher quality of life pertaining to swallowing.

Despite the progressive nature of the myopathic changes typically described in patients with nephropathic cystinosis, we demonstrated improvement in some swallowing metrics. This may suggest a possible late-onset effect of respiratory training or cognitive-behavioral impact from repeated swallowing measurements.