What causes fecal incontinence in children?

Fecal incontinence is a symptom that occurs in both the elderly and children, and the causes of fecal incontinence are very complex. And when a person suffers from fecal incontinence, it directly means that the person's normal ability to move is gone. However, when children suffer from fecal incontinence, their parents are the most worried. So what are the causes of fecal incontinence in children?

Causes

1. Causes of disease

1. Congenital malformation of the anus

(1) Developmental defects of the nervous system: Congenital lumbar meningocele or spina bifida may be accompanied by anal incontinence. The patient's external sphincter and puborectalis muscle lose their normal nerve innervation, have no contraction function, and are in a relaxed state. And because both the sensory and motor systems are affected, the rectal mucosa lacks a sense of expansion when filled with feces, cannot arouse the urge to defecate or initiate defecation, and the feces in the rectum can be discharged at any time. Children with this disease often suffer from urinary incontinence.

(2) Anorectal malformation: The anorectum itself and the pelvic structure undergo changes, and the higher the blind end of the rectum, the more obvious and complex the changes. In high-position deformity, the blind end of the rectum is located above the pelvic diaphragm, the puborectalis muscle is shortened and obviously displaced forward and upward; the internal sphincter is absent or only in its rudiments; the external sphincter is mostly in a loose state, filled with fat tissue, and the muscle fibers have abnormal and disordered course. A reporter followed up 225 children after surgery for anorectal malformations, and found that 80 cases (35.5%) had varying degrees of fecal soiling or incontinence. The higher the location of the malformation, the higher the incidence of incontinence. The cause of the disease is mainly related to the deformity accompanied by defects in the sensory and motor nerve tissue structure, and is also significantly related to surgical injuries and surgical errors. In the past, when abdominoperineal anoplasty was performed to treat high-positioned deformities, the rectum did not pass through the puborectalis muscle ring but descended behind it. Anorectal malformations, especially high-positioned malformations accompanied by sacral malformations, are not uncommon in patients with neurological deficits. According to Jiehioiiikhh's analysis, about 10% of postoperative anal incontinence is caused by this reason. The main causes of anal incontinence after surgery for middle and low-position deformities are surgical injury, infection and other factors. For example, cloaca malformation, mainly in which the rectum, anal canal, urethra and vagina of female infants are combined into one hole, and infants with high-positioned anus often suffer from fecal incontinence after surgery. Congenital dementia, meningocele, multiple scleroderma, etc. can all cause fecal incontinence.

2. Trauma

Due to traumatic damage to the anorectal ring, the sphincter loses its sphincter function and leads to fecal incontinence. Such as stab wounds, cuts, burns, frostbite and lacerations (mainly perineal lacerations during childbirth), as well as injuries from anorectal surgery, such as anal fistula, hemorrhoids, rectal prolapse, rectal cancer, etc., which damage the anal sphincter and cause fecal incontinence.

3. Nervous system diseases

It is common in brain trauma, brain tumors, cerebral infarction, spinal cord tumors, spinal tuberculosis, cauda equina injury, etc., which can all lead to fecal incontinence.

4. The most common anorectal disease is anorectal tumors; such as rectal cancer, anal canal cancer, Crohn's disease invading the anorectum and affecting the anal sphincter, or long-term diarrhea caused by ulcerative colitis causing anal canal inflammation, or anal relaxation caused by rectal prolapse, and severe scars around the anus affecting the anal sphincter, resulting in anal atresia, which can all cause fecal incontinence.

2. Pathogenesis of fecal incontinence in children

1. Pathophysiology Defecation is a coordinated and unified process involving multiple systems of the human body. When feces reaches the rectum, the rectum must first have a certain degree of compliance to accept the feces, normally 250 ml. When the contents of the rectum reach a certain amount, it stimulates the rectal receptors, is transmitted to the central nervous system through the afferent nerve fibers, and then reaches the external sphincter and levator ani muscle through the efferent nerve fibers. When the central nervous system determines that conditions permit, the external sphincter relaxes and the intra-abdominal pressure increases to complete defecation. When defecation is not allowed for some reason, the external sphincter compresses the internal sphincter through voluntary contraction, causing the internal sphincter to retrogradely inhibit rectal contraction, thereby expanding the rectum and increasing its volume, or pushing feces back into the sigmoid colon through reverse peristalsis of the rectum, and the urge to defecate disappears. This kind of reverse inhibition of rectal contraction by stimulating the internal sphincter through voluntary contraction of the external sphincter is called voluntary inhibition. Defecation is a very complicated process, and damage to any link can cause fecal incontinence. If the compliance of the rectum is too low, it may lead to a severe increase in the frequency of bowel movements or even fecal incontinence. If the compliance is too high, it may cause the volume of the rectum to increase and the patient may experience constipation. Fecal incontinence may also occur if voluntary inhibition is reduced, as well as if the rectal receptors are abnormal or the external sphincter is damaged. In short, there are many causes of fecal incontinence, which need further exploration.

2. Classification

(1) Classification by degree: According to the different degrees of fecal incontinence, it can be divided into two types: complete and incomplete anal incontinence.

① Incomplete anal incontinence: loose stools and gas cannot be controlled, but dry stools can be controlled.

② Complete anal incontinence: dry stools, loose stools and gas cannot be controlled.

(2) Classification by nature: According to the nature of anal incontinence, it is divided into sensory incontinence and motor incontinence.

. ① Sensory anal incontinence: The morphology of the anal sphincter is normal, but the lower rectum lacks sensation, such as anal incontinence caused by dysfunction of the spinal cord or central nervous system of the brain; or anal incontinence caused by low rectal compliance and severe increase in the frequency of bowel movements.

② Sports anal incontinence: mainly caused by damage to the external anal sphincter, which destroys the anorectal ring and causes the patient to be unable to control defecation at will.