The neurological basis of genital numbness has not been defined and requires further investigation. We describe the clinico-neurophysiologic phenotype of a cohort of non-neurological individuals with isolated genital numbness.

Genital numbness is an uncommon presenting symptom and identifying the cause can be challenging. Localisation of genital numbness may be at the level of the conus medullaris, cauda equina, sacral nerve roots or pudendal nerve from origin to distal branches. The aetiology of genital numbness may be focal lesion due to compression, inflammation or due to a peripheral neuropathy. Several medications are increasingly recognised to affect genital sensation.

Consecutive referrals with impairment of genital sensation to a tertiary referral centre from 2018 to 2023 were included. Urogenital clinical symptoms (sexual, bladder and bowel symptoms), contributing factors and past medical history were recorded. Pelvic sensory examination (pinprick and von frey hair, VFH) was performed at the time of sacral sensory neurophysiology testing.

42 Individuals were identified with genital numbness (female, 35.1%). The median age was 37.5 years (IQR 14.1). There were no significant differences in baseline characteristics between the groups. Eight (19%) had abnormal neurophysiology. An abnormal clinical examination with both VFH and pinprick significantly predicted abnormal pelvic neurophysiology (OR 50.94, p=0.012).

We present the first isolated genital numbness cohort with a clinic-neurophysiologic profile to date. Firstly, a normal clinical pelvic sensory examination was associated with normal neurophysiology, therefore this group of individuals do not need further investigation. Secondly, an abnormal examination with both sensory modalities was highly predictive of abnormal neurophysiology (OR 50.94). There were no additional independent factors which predicted abnormal neurophysiology. Evidence for peripheral nerve injury does exist in a small cohort (19%) and further investigations are required to explore an underlying neuropathy. This indicates a significant proportion of non-neurogenic genital numbness is centrally mediated which requires further research.