Internal anal sphincter atrophy in patients with systemic sclerosis

Objectives. SSc is a connective tissue, multisystem disorder of unknown aetiology. The gastrointestinal tract (GIT) is affected in up to 90% of patients. The exact pathophysiology of GIT involvement is not known, but it is related to both neurogenic and myogenic abnormalities as well as possible vascular and ischaemic changes. Thinning of the internal anal sphincter (IAS) has been demonstrated in SSc with faecal incontinence. We aimed to investigate anal sphincter structure in patients with SSc. Methods. Forty-four SSc patients [24 symptomatic (Sx) and 20 asymptomatic (ASx)] and 20 incontinent controls (ICs) were studied. Patients underwent anorectal manometry and endoanal US. Results. In the ICs, external anal sphincter defects were more common, but the IAS was less atrophic, evident by both atrophy scores and IAS thickness. There was no significant difference in atrophy scores [Sx: 2 (1.5-3) vs ASx: 2 (1-2)] or IAS thickness [Sx: 1.85 (1.5-2.3) vs ASx: 1.8 (1.7-2.25)] between the Sx and ASx SSc patients. Conclusion. Patients with SSc (both Sx and ASx) have thin and atrophic IAS, suggesting that IAS atrophy develops even in ASx patients and this may be amenable to treatment with sacral neuromodulation.