To determine the frequency and symptomatic burden of neurogenic lower urinary tract dysfunction in patients with familial dysautonomia (FD).

FD is a rare genetic disease caused by a founder mutation in the IKBKAP gene characterized by impaired development of sensory and afferent autonomic nerves. Some patients with FD complain of urinary symptoms but there are no reports on frequency and characteristics.

We studied consecutive patients with FD between October 2017 and September 2018. All patients underwent urinalysis and ultrasound bladder post-void-residual (PVR) volume measurement; and completed the following symptom scales: International Prostate Symptom Score (IPSS), International Consultation on Incontinence Questionnaire on Urinary Incontinence-Short-Form (ICIQ-UI-SF), and Qualiveen-SF. We also performed a chart review to document renal ultrasound and urinary tract infections (UTI) within the past 5 years. To define medications anticholinergic and sedative effect we used the Anticholinergic Drug Scale (ADS). The Brief Ataxia Rating Scale (BARS) was used to evaluate motor disability.

We studied 45 patients (22 men, 23 women, 24.3±13.1 years). Mean PVR was 54.2±13.1 ml. Five patients (11.6%) had a PVR>100 ml indicating underactive bladder. Patients had a low burden of lower urinary tract symptoms [IPSS: 4.5±4.1 (out of 35); ICIQ-UI-SF: 1.9±3 (out of 21), Qualiveen-SF: 0.3±0.3 (out of 32)]. The PVR was not associated with symptom scores. Of the 15 patients who had renal ultrasound available, 1 had mild hydronephrosis. Urinary retention was not associated with frequency of UTI. Patients with urinary retention had higher anticholinergic side effect burden (ADS score: 4.2 vs. 1.3; P=0.0179) and worse ataxia (BARS score: 19.8 vs. 13.2, P=0.0272) than those without retention.

Neurogenic detrusor underactivity was present in 15% of patients with FD. Importantly, patients with detrusor underactivity were more frequently receiving anticholinergic medications and had greater disease-related motor disability. This has therapeutic implications.