The intussusceptum itself may mechanically obstruct the rectoanal lumen, creating a blockage that straining, anismus and colonic dysmotility exacerbate.Some believe that internal rectal intussusception represents the initial form of a progressive spectrum of disorders the extreme of which is external rectal prolapse. The intermediary stages would be gradually increasing sizes of intussusception. However, internal intussusception rarely progresses to external rectal prolapse. The factors that result in a patient progressing from internal intussusception to a full thickness rectal prolapse remain unknown. Defecography studies demonstrated that degrees of internal intussusception are present in 40% of asymptomatic subjects, raising the possibility that it represents a normal variant in some, and may predispose patients to develop symptoms, or exacerbate other problems. Treatment
Conservative
Surgery is thought to be the only option to potentially cure a complete rectal prolapse. For people with medical problems that make them unfit for surgery, and those who have minimal symptoms, conservative measures may be beneficial. Dietary adjustments, including increasing dietary fiber may be beneficial to reduce constipation, and thereby reduce straining. A bulk forming agent (e.g. psyllium) or stool softener can also reduce constipation. Surgical
Surgery is often required to prevent further damage to the anal sphincters. The goals of surgery are to restore the normal anatomy and to minimize symptoms. There is no globally agreed consensus as to which procedures are more effective, and there have been over 50 different operations described.Surgical approaches in rectal prolapse can be either perineal or abdominal.
Symptoms of internal intussusception overlap with those of rectocele, indeed the 2 conditions can occur together.Patients with solitary rectal ulcer syndrome combined with internal intussusception (as 94% of SRUS patients have) were shown to have altered rectal wall biomechanics compared to patients with internal intussusception alone. The presumed mechanism of the obstructed defecation is by telescoping of the intussusceptum, occluding the rectal lumen during attempted defecation. One study analysed resected rectal wall specimens in patients with obstructed defecation associated with rectal intussusception undergoing stapled trans-anal rectal resection. They reported abnormalities of the enteric nervous system and estrogen receptors. One study concluded that intussusception of the anterior rectal wall shares the same cause as rectocele, namely deficient recto-vaginal ligamentous support. Comorbidities and complications
The following conditions occur more commonly in patients with internal rectal intussusception than in the general population:

Rectocele
Solitary rectal ulcer syndrome. Diagnosis
Unlike external rectal prolapse, internal rectal intussusception is not visible externally, but it may still be diagnosed by digital rectal examination, while the patient strains as if to defecate. Imaging such as a defecating proctogram or dynamic MRI defecography can demonstrate the abnormal folding of the rectal wall. Some have advocated the use of anorectal physiology testing (anorectal manometry). Treatment
Non surgical measures to treat internal intussusception include pelvic floor retraining, a bulking agent (e.g. psyllium), suppositories or enemas to relieve constipation and straining. If there is incontinence (fecal leakage or more severe FI), or paradoxical contraction of the pelvic floor (anismus), then biofeedback retraining is indicated.