The Internal Anal Sphincter in Systemic Sclerosis

Abstract

Available literature suggest that internal anal sphincter in systemic sclerosis is invariably thinned and hyperechoic. This series suggests that two distinct morphologic changes are possible.

Vascular events are risk factors for anal incontinence in systemic sclerosis: a study of morphology and functional properties measured by anal endosonography and manometry

“…The internal sphincter of SSc patients with AI has been described as both thin and thick, as well as with endosonographic signs of atrophy such as a hyperechoic sphincter (9,13). In the present study we confirm that the internal sphincter is thinner than in healthy controls, and also show that the external sphincter had normal thickness.…”

“…The most proximal part of the oesophagus and the external sphincter of the anal canal are composed of striated muscle and usually unaffected in SSc whereas the lower part of the oesophagus and the internal sphincter of the anal canal are composed of smooth muscle, which is often affected in SSc. There are, however, reports on a thicker internal anal sphincter but it is unclear whether this is due to a specific subgroup of SSc patients with AI with more collagen deposition (9). Furthermore, measurement of the internal sphincter thickness does not provide information on sphincter function.…”

“…The sphincters may show signs of atrophy, fibrosis, and possibly vasculopathy. In addition, neuropathy throughout the rectal walls including the sphincters will contribute to AI (9,10). As well as pathology, naturally occurring events outside the anal sphincter, such as diarrhoea, neurological disorders, age, and obstetric trauma, may lead to AI.…”

Faecal incontinence in patients with systemic sclerosis: is an impaired internal anal sphincter the only cause?

“…This result strongly supports the idea that poor function of the smooth internal anal sphincter muscle causes faecal incontinence in SSc. Others have shown a reduced anal resting pressure in SSc patients (12)(13)(14)(24)(25)(26), and by means of ultrasonography, some authors have found either fibrosis and thinning (12) or oedema and thickening (27) of the internal anal sphincter.…”

Patient subgroups and potential risk factors in systemic sclerosis: is there a possibility of an early diagnosis?

“…It may be complicated by colonic telangiectasia and pseudodiverticula, leading to bleeding and obstruction. The involvement of the anal sphincter together with rectum collagen deposition may lead to fecal incontinence that is reported in up to 38% of SSc patients [81].…”