BOWEL INCONTINENCE IS ONE OF THE MOST PSYCHOLOGICALLY AND SOCIALLY DEBILITATING CONDITIONS in an otherwise healthy individual. It can lead to social isolation, loss of self-esteem and self-confidence, and depression as the affected person is unable to control the discharge of bowel contents despite inappropriate situations or timing.
Total anal incontinence is probably not common but minor degrees of incontinence is very common. Partial or minor incontinence may include incontinence of flatus, liquid stool or mucus. Different degrees of bowel incontinence may overlap, ranging from severe to minor in nature. And even within each category, incontinence may be occasional or constant. Many “normal” people for example may occasionally have minor staining of stool or mucus on their underwear especially when stools are diarrhoeic or there is associated anxiety or nervousness.
While direct lack of control over bowel contents is bad enough, indirect effects - for example severe itching sensation from the anus, irritation and inflammation of the skin around the anus, skin excoriations and discharge - are major problems as well for affected patients.
To understand better the causes of incontinence, let’s first look at the factors that are responsible for normal continence, many of which are inter-related. A breakdown of any of its components may therefore result in incontinence. The major players in this regard concerns the muscles around the anus, the sensory nerves of the anus and rectum and the consistency of the stools within the rectum. Any injury or disease affecting the ability of the anal muscles to contract appropriately in response to faeces within the rectum may affect anal continence. An intact sensation is also important. Thus, if the anus and rectum is unable to appropriately detect the nature of the rectal content, the patient may unknowingly pass solid faeces when he was only willing to pass flatus.
The rectum needs to be sufficiently big to store stool until defecation. The rectal walls need to be able to distend to accommodate stool. Furthermore, the nature and speed with which contents are passed into the anus or rectum is also important in the control of faeces. A patient with very liquid stool or with a hyperactive contracting colon may find it hard to maintain continence in spite of a normal anal musculature and sensation.
Bowel incontinence therefore is a symptom only and may be due to a long list of causes. Up to 80 per cent of patients may have more than one abnormality causing incontinence. Sometimes deficits of some functional components can be compensated for some period of time, until the compensating components themselves are unable to maintain continence.
The most common causes of incontinence are obstetric and ano-rectal injuries and inappropriate surgeries as well as diseases like fistula and rectal prolapse. Prolonged childbirth may injure the pudendal nerve leading to various degrees of immediate or delayed incontinence later in life. Traumatic injuries to the anal sphincters may result from assault, accidents and even insertion of foreign bodies into the rectum and anal sex.
Other causes relate to sphincter trauma and degeneration, or neurological disorders. Inflammatory bowel diseases and irritable bowel syndrome may also cause incontinence by its resultant watery diarrhoea. Diabetes mellitus may result in incontinence by affecting sensory nerves within the rectum and anus. Radiation therapy may also affect the ano-rectal muscles, nerves as well as rectal distensibility leading to incontinence.
Liquid stool is more difficult to control than formed, solid stool. Diarrhoea is one of the most common cause of temporary incontinence. Chronic conditions, such as irritable bowel syndrome or Crohn’s disease, can cause severe diarrhoea lasting for a long time.
Identification of the exact causes can be made first by a thorough medical history followed by a thorough physical examination including digital examination to assesses the anal muscles and other disorders if present. Testing of the anorectal muscles and nerves can be performed by anorectal physiology testing. 结肠镜检查 may be needed to assess the nature of any bowel pathology present. Traditional or MRI defecography may be helpful to assess defects of defecation. Endoanal ultrasound can be used for the detection of anal canal injuries. Other tests may be needed as the situation dictates.
Faecal incontinence has an impact on all aspects of peoples’ lives, and not just physical and mental health, but also personal, social and professional life.
Persons with this symptom are frequently ostracized socially. In older people, it is one of the most common reasons for admission into a care home. Persons who develop bowel incontinence are less likely to get useful employment. Often, people will go to great lengths to keep their condition secret. It has been termed “the silent affliction” since many do not discuss the problem with their close family, employers or clinicians.
However, patients should not suffer in silence. There are many effective treatments available for such patients currently and a consult with an anorectal specialist with an interest in such problems can be very rewarding and helpful for these patients.
Symptoms of incontinence may worsen over time but minor incontinence is generally treatable with conservative management. Surgery may be needed if this fails or if major incontinence is present. Success depends upon the exact causes and how easily these are corrected. The treatment of choice depends usually on the cause and severity of disease. Conservative measures include dietary modification, drug treatment, retrograde anal irrigation, biofeedback retraining, anal sphincter exercises.
Incontinence products refer to devices such as anal plugs and perineal pads and garments such as diapers/nappies. Perineal pads are efficient and acceptable for only minor incontinence.
Dietary advice must be tailored to address the underlying cause or it may be ineffective or counter productive. In persons with diarrhoea, treatment of diarrhoea or a reduction of the cause of diarrhoea e.g. lactose if there is lactase deficiency, is important.
Anti-diarrhoeal agents is always helpful in these patients. Biofeedback is a commonly used and researched treatment, but the benefits are uncertain. The role of pelvic floor and anal phincter exercises are poorly documented.
Surgery may be carried out if needed and there are many surgical options. The optimal treatment regime may be a complex combination of various surgical and non-surgical therapies. The surgical options are to improve poor anal muscles function e.g. sphincter repair, sacral nerve stimulation, dynamic graciloplasty where a thigh muscle is used to reconstruct the anal muscle, use of injectable bulking agents to bulk weak muscles, artificial bowel sphincter or even the use of antegrade continence enema.
Finally, if nothing works, faecal diversion i.e. colostomy or even resection of the anus can be considered if necessary. Isolated sphincter defects may be treated with sphincter repair and if this fails, the person can be assessed for sacral nerve stimulation. Functional deficits of the anal muscles where there is no structural defect, or only limited muscles structural defect, may be suitable for sacral nerve stimulation. If this fails, neosphincter with either dynamic graciloplasty or artificial anal sphincter may be indicated.