Functional Disorders

Abstract

6.1

Continence is defined as the voluntary control of bowel content and the ability of its voluntary emptying. Incontinence is the loss of this ability. Incontinence must also be considered a symptom. Its causes are manifold. Incontinence can be directly related to the anorectal continence organ itself, or be a secondary symptom to various pathological conditions (Table 6.1.1). Traditionally incontinence was described as being sensory, muscular, neurogenic, mixed, psychoorganic and idiopathic. These categories carry limitations as they do not take factors determining continence into consideration, such as:

• Stool frequency

• Stool consistency

• Sphincter strength

• Anorectal sensitivity

• Capacity and compliance of the rectum

Especially with regard to a required therapy, a treatmentoriented structuring makes sense (Table 6.1.1). Incontinence is mostly multifactorial. If incontinence occurs secondary to another underlying disease or disorder, treatment should be directed to the primary. The following is focused on incontinence due to disorders of the anorectal continence organs.

6.2

The term constipation covers several forms and causes of impaired defaecation. The differentiation between acute and chronic constipation is important (Fig. 6.2.1).

• An acute constipation is the sudden inability to empty the bowel. The most common reasons are colonic obstructions (carcinoma, inflammation) or painful anal lesions that lead to sphincter spasm or the inability to relax (e.g. fissure-in-ano, intersphincteric abscess). In particular diverticulitis and colonic carcinoma can lead to a mechanical colonic ileus (obstruction).

• In chronic constipation defaecation is irregular with a frequency of two or less evacuations per week. Another definition is “straining at stool for more than 25% of the time”. Chronic constipation itself can divided into:

- Colonic slow-transit constipation

– Outlet obstruction (Chap. 6.3)

In this chapter, we will concentrate on slow-transit constipation.

6.3

Defaecation disorders refer to the inability to efficiently and rapidly empty the rectum of its contents on demand. They are clearly a source of discomfort and impair significantly the quality of life of affected patients.

Defaecation disorders represent a complex field where throughout detailed assessment of the terminal bowel anatomy and function is needed.

A multi-disciplinary approach as developed in “pelvic floor clinics” is a useful adjunct to the traditional colorectal approach.

Medical treatment and pelvic floor retraining are first-line treatment. Various types of surgical approaches currently designed to correct anatomical abnormalities and improve function can be carried out in selected patients.

In this difficult area of functional disorder, information to the patient and his/her relatives is essential, especially when surgery is considered.

6.4

• Rectal prolapse is an uncommon but disabling condition that requires surgical correction to treat symptoms and prevent progressive anal sphincter damage. The majority of patients complain of perineal pressure and a feeling of “something coming down”. This is commonly associated with mucus discharge or frank faecal soiling. Many patients will describe a protrusion through the anal opening, that may reduce spontaneously, but frequently, with time, manual reduction is required. There is considerable controversy regarding the indications for surgical intervention and the most appropriate surgical technique to be used.

• Rectal intussusception is a common finding at defaecography and may be present in normal subjects; internal rectal prolapse is a term used in patients with obstructed defaecation and in whom this proctographic finding is identified.

• Solitary rectal ulcer is a term used to describe ulceration, usually on the anterior rectal wall, at the level of the puborectalis sling. Local trauma due to repeated straining with intussusception and obstructed defaecation is thought to be responsible.

• In terms of treatment, intussusception and internal prolapse, with or without ulceration, are generally treated conservatively.

6.5

• Irritable bowel syndrome (IBS) (synonym: spastic colon) is characterised by abdominal discomfort or pain, associated with altered bowel function (diarrhoea and/ or constipation) and disordered defaecation.

• There are no diagnostic biochemical, physiological or structural abnormalities in IBS.

Over the years groups of experts have developed clinical measures based on positive symptom analysis. Manning and colleagues were the first to propose key symptoms (“Manning criteria”) to help the diagnosis of IBS. The Rome I, II and III criteria are the results of multinational consensus workshops. Table 6.5.1 lists the symptom-based criteria which are so far established for the diagnosis of IBS. The Rome classification system characterises IBS in terms of multiple physiological determinants contributing to a common set of symptoms rather than a single disease entity. The current Rome III criteria subtype IBS according to the stool form by using the Bristol Stool Form Scale.

The IBS-related symptoms overlap with those of other diseases. Experienced clinicians often diagnose these disorders on symptoms alone, but, as functional disorders are so much more common than organic diseases, any diagnostic strategy is likely to have a deceptively high positive predictive value.