Pediatric constipation

　　1. Etiology

　　Simple constipation is often caused by an increase in water absorption in the colon, common causes include:

　　1. Insufficient diet

　　When infants eat too little, the absorption of digestive fluids is reduced, leaving less residue, leading to reduced stool volume and thickness. If the sugar content in milk is insufficient, intestinal motility is weak, which can cause dry stool. Prolonged periods of insufficient food intake can lead to malnutrition, and a decrease in abdominal and intestinal muscle tone, even atrophy, can weaken contraction strength, forming a vicious cycle that worsens constipation.

　　2. Inappropriate food composition

　　The nature of stool is closely related to the composition of food. For example, if food contains a large amount of protein but insufficient carbohydrates, the fermentation by intestinal flora of intestinal contents decreases, and the stool tends to be alkaline and dry; if food contains more carbohydrates, the number of intestinal fermentation bacteria increases, the fermentation is enhanced, acid production is high, and the stool tends to be acidic, frequent, and soft; if both fat and carbohydrates are high in the diet, the stool is slippery; if a large amount of calcified casein is consumed, the stool contains a large amount of indissolvable calcium soaps, the stool volume is large, and constipation is more likely; carbohydrate foods such as rice and flour are more likely to cause constipation than cereal foods; children with a preference for food can easily develop constipation, as many children prefer meat and eat little or no vegetables, resulting in a lack of dietary fiber.

　　3. Intestinal dysfunction

　　It is common for constipation to occur due to irregular lifestyle and not defecating on time, leading to the lack of a conditioned reflex for defecation. Additionally, school-age children often cannot defecate at any time during class due to the lack of a morning defecation habit, and holding in stool is also a common cause of constipation. The use of laxatives or enemas, lack of physical activity, or chronic diseases such as malnutrition, rickets, hypercalcemia, dermatomyositis, cretinism, and congenital myasthenia gravis, all due to weakened intestinal muscle strength and dysfunction, can lead to constipation. Abnormal function of the sympathetic nervous system, weak or paralyzed abdominal muscles, also often causes constipation. Certain medications can reduce intestinal motility and cause constipation, such as anticholinergic drugs, antacids, certain anticonvulsants, diuretics, and iron supplements.

　　4. Abnormal physical and physiological conditions

　　Conditions such as anal fissure, anal stenosis, congenital megacolon, spina bifida, or tumor compression of the cauda equina can all cause constipation. An anal, lower spine, and perineal examination should be conducted. Some children may have constipation from birth, and if there is a family history, it may be related to heredity.

　　5. Mental factors

　　Children can also experience short-term constipation due to sudden emotional stress or sudden changes in their environment and living habits.

　　Secondly, pathogenesis

　　1. Conscious inhibition of defecation

　　This can make defecation stimulation disappear. The stool thus becomes dry, causing pain during defecation, and this condition can further suppress defecation. Possible reasons for voluntarily inhibiting defecation include: children being too playful and not having time to defecate; being afraid of being late for class and not daring to spend time defecating; or not daring to ask the teacher for permission to go to the toilet during class; or not knowing the location and direction of the toilet. Inpatients may have the intention to defecate but may not be known to medical staff; children over 4 years old may hope to use the toilet alone; during long-distance travel, the defecation routine is often disrupted; being far from familiar homes, feeling anxious and restless in unfamiliar environments, and being unable to get used to the toilets there, all of these. During the training period for children's defecation habits, teach them to defecate or hold it in based on their own wishes, and from then on, the child will act according to their own will. Punishment, unpleasantness, and forced defecation training can make children reactively hold in stool and refuse to cooperate.

　　2. Spinal cord disease

　　When the spinal cord is blocked above the defecation center, the ability to voluntarily control defecation is lost, and defecation becomes a reflex action. If the defecation center is damaged, the entire rectal sensation is lost, leading to fecal incontinence. The normal control of the rectum is carried out by the actions of the anal internal sphincter (reflexive control) and the anal external sphincter (reflexive and voluntary control) together. Rectal incontinence only occurs when the somatic nerve innervating the external sphincter is damaged. In this case, the distended rectum can only be emptied by the reflexive relaxation of the internal sphincter. The loss of voluntary and reflexive actions of the external sphincter leads to rectal incontinence, which can be seen in spinal cord injuries, meningocele, spinal dysraphism, longitudinal cleft of the spinal cord, and spinal tumors, etc.

　　1. Anal and rectal complications

　　Long-term constipation can stimulate the intestinal mucosal epithelial cells by carcinogenic substances produced by bacterial fermentation in the intestines, leading to atypical hyperplasia and an increased risk of canceration. Constipation can cause perianal diseases such as proctitis, anal fissure, and hemorrhoids, and due to constipation, difficulties in defecation and dry stool can directly cause or worsen anal and rectal diseases. Hard stool blocks the intestinal lumen, causing narrowing of the lumen and compression of the surrounding structures in the pelvic cavity, obstructing colonic peristalsis, and causing circulatory disorders in the rectum or colon. It can also form fecal ulcers, and in severe cases, it can cause intestinal perforation. Colon diverticulosis, intestinal obstruction, and gastrointestinal neurological dysfunction (such as lack of appetite, abdominal distension, belching, bitter taste in the mouth, excessive anal flatus, etc.) may also occur.

　　2. Extraintestinal complications

　　Such as stroke, affecting brain function (decreased memory, attention deficit, dull thinking), sexual dysfunction, etc. It also plays an important role in the occurrence of diseases such as hepatic encephalopathy, breast diseases, and Alzheimer's disease. Clinically, there is a trend of increasing annual incidence of cardiovascular disease发作 due to increased abdominal pressure, straining, and hard defecation caused by constipation, such as诱发 angina, myocardial infarction发作.

　　1. Dry and hard stool

　　The child has a decrease in defecation frequency, dry and hard stools, difficulties in defecation, and anal pain. Sometimes, the stool can scrape the intestinal mucosa or anus, causing bleeding, and a small amount of blood or mucus may be present on the surface of the stool. Stool that stays in the intestines for too long can also reflectively cause systemic symptoms, such as lack of spirit and appetite, fatigue, dizziness, headache, and loss of appetite. Long-term insufficient intake of food can lead to malnutrition, further aggravating constipation, forming a vicious cycle. If stool stays in the rectum for too long, it can cause local inflammation, with a sensation of falling. Sometimes, children with constipation may have a strong urge to defecate but cannot empty their bowels completely, resulting in an increase in defecation frequency. Severe constipation can cause the stool to become blocked locally, and intestinal secretions may inadvertently leak around the dry stool, resembling incontinence of feces. Constipation is a common cause of intestinal colic.

　　2. Abdominal distension, abdominal pain

　　Feelings of abdominal distension and hidden pain in the lower abdomen, intestinal rumbling and excessive flatus. Occasionally, severe constipation children may experience sudden abdominal pain, start to pass hard stools, followed by the discharge of malodorous loose stools, which is called 'heat constipation' in traditional Chinese medicine.

　　3. Rectal prolapse

　　Chronic constipation can lead to hemorrhoids or rectal prolapse.

　　For children over three years old, remind them to defecate after breakfast and dinner every day, and do not make the defecation time too short. Encourage them to defecate as thoroughly as possible. Regardless of whether defecation occurs each time, they must go to the toilet on time every day to develop the good habit of defecating on time. The large intestine can only recover good defecation function after a period of treatment for constipation. Good defecation and dietary habits should be cultivated during the treatment period, and then the medication can be stopped to prevent the recurrence of constipation.

　　1. Gastrointestinal X-ray barium enema

　　The movement function of the colon can be understood according to the situation of barium movement in the gastrointestinal tract, distinguishing between hypotonic constipation and spastic constipation, and promptly detecting organic lesions such as congenital megacolon, tumor, tuberculosis, etc.

　　2. Rectoscopy

　　Sigmoidoscopy and fiberoptic colonoscopy can directly understand the condition of the intestinal mucosa. Due to constipation, the retention and stimulation of feces, the colon mucosa, especially the rectal mucosa, often shows varying degrees of inflammatory changes, such as congestion, edema, and unclear blood vessel direction. In addition, in spastic constipation, there can be contractile contractions of the intestinal tract and narrowing of the intestinal lumen.

　　3. Anorectal manometry

　　Anorectal manometry is a commonly used technique in pediatrics to understand rectal and anal dysfunction. In children with severe constipation, manometry can be used to determine the resistance of rectal dilation, the resting tension of the anal canal, the strength of voluntary anal muscle contraction, and the child's self-perception of rectal dilation. It can also evaluate the reflexes of the anal sphincter. Attention must be paid to the operation by experienced personnel to avoid incorrect results. According to Karen's research on the anorectal and distal colonic dynamics of children with chronic constipation, almost all cases have functional abnormalities.

　　4. Electromyography

　　Electromyographic observation of the pelvic floor muscles and external anal sphincter is a useful method for evaluating chronic constipation. In normal individuals, the tension of the pelvic floor striated muscles is maintained in a tense state at rest. The application of surface skin electrodes for detection shows that the tension of the external anal sphincter decreases during defecation in all normal children, while only 42% of children with constipation show a decrease in electromyographic activity of the puborectalis muscle or external anal sphincter.

　　5. X-ray defecography

　　In recent years, due to the clinical application of defecography, static and dynamic observations can be made on the anal sphincter and anorectal area, and photographs can be taken quickly (2-4 per second), allowing for continuous observation of the entire process of defecation. It is found that some constipation is due to varying degrees of obstruction at the outlet, such as rectal intussusception, anterior rectal prolapse, pelvic floor muscle spasm syndrome, etc. These obstructions are difficult to detect by clinical and endoscopic examinations and do not belong to the category of habitual constipation in fact.

　　Children with malnutrition constipation should pay attention to supplementing nutrition, gradually increasing intake, and after the nutritional condition improves, the abdominal and intestinal muscles grow, the tension increases, and defecation naturally becomes smooth..

　　For patients with primary diseases, actively treat the primary diseases (such as hypothyroidism, etc.). The fundamental treatment of simple constipation should be placed on improving the content of diet, increasing water intake and foods rich in fiber (such as grains, vegetables, etc.), while cultivating the habit of defecation. Medication should only be used temporarily when necessary.
　　1. Diet correction for infants breastfed by mother
　　Infants breastfed by mother have less constipation. If constipation occurs, in addition to breastfeeding, additional lubricating complementary foods such as fresh vegetable juice and fruit juice can be added.
　　2. Diet correction for infants fed artificially
　　Infants fed artificially are more prone to constipation, but reasonable addition of sugar and complementary foods can prevent constipation.
　　3. Training Habit
　　Defecation is a conditioned reflex movement. Children, after training, can develop the habit of defecating on time.
　　4. Medication
　　(1) Phthalein takes effect 6 to 8 hours after administration. Due to the small amount of absorption and the enterohepatic circulation, its effect can sometimes last for 3 to 4 days. It is suitable for habitual constipation.
　　(2) Liquid paraffin taken orally before bedtime, effective 6 to 8 hours after administration. Long-term use can lead to malabsorption of fat-soluble vitamins and calcium, phosphorus.
　　(3) Magnesium milk taken orally before bedtime.
　　(4) Glycerin栓塞入肛门，为轻刺激性导泻药，用药后数分钟即可排便。
　　(5) Glycerin/sodium chloride (contains sorbitol, glycerin, or magnesium sulfate) first apply a small amount to moisten the anus, then slowly insert it into the anus to squeeze the medication into the anus, defecation will occur within a few minutes.
　　(6) Simple method: at home, you can wear rubber gloves and use the little finger to dab a small amount of liquid paraffin (paraffin oil) or Vaseline, insert it into the anus for defecation.
　　(7) Enema using 1% to 2% soap water or normal saline, with a temperature close to room temperature. Enema has strong irritability and should not be used unless there is a special need.