Diarrhea

腹泻

Frequent loose bowel movements (4 to 6/day) may occur in normal infants; they are of no concern unless anorexia, vomiting, weight loss, failure to gain weight, or passage of blood also occurs. Breastfed infants tend to have frequent bowel movements, especially if they are not receiving solid food. The significance of diarrhea in a child at any age differs if it is acute (< 2 wk) or chronic (> 2 wk).

正常婴儿一天可多次稀松排便（4－6次/天)。这不用担心，除非有厌食、呕吐、体征减轻、长不胖、便血等情况。母乳喂养婴儿排便次数较多，特别是在未添加固体食物情况下。任何年龄儿童腹泻意义各不相同，还要看是否是急性< 2 wk)或慢性（> 2 wk)。

Etiology

病因学

Acute diarrhea is most likely infectious, especially if onset is sudden or accompanied by vomiting, bloody stools, fever, anorexia, or listlessness. Diagnosis is clinical, and treatment is supportive until the condition resolves spontaneously.

急性腹泻最可能是感染性，特别是起病突然或伴有呕吐、便血、发烧、厌食或无精打采等情形。予门诊诊断、支持性治疗，直到病情自行消退。

Chronic diarrhea is usually more significant. Causes include gluten-induced enteropathy, cystic fibrosis, sugar malabsorption, and allergic gastroenteropathy. Inflammatory bowel disease and some infections (eg, with Giardia) can also cause chronic diarrhea.

慢性腹泻较重要，其原因包括可谷胶所致肠病、囊性纤维病、糖吸收不良及过敏性胃肠病。炎性肠病和一些传染病（如贾第虫性)也能引起慢性腹泻。

With gluten-induced enteropathy (celiac sprue), the gluten fraction of wheat protein causes intestinal mucosal damage and malabsorption of dietary fats, resulting in malnutrition, anorexia, and bulky, foul-smelling stools. The change in stools starts when wheat and other gluten-containing foods are added.医学.全在线www.med126.com

谷胶所致肠病：小麦蛋白谷胶引起肠粘膜损坏和饮食脂肪吸收不良，导致营养不良、厌食，大便成团、恶臭。当麦和其他含谷胶食物增加时大便就会发生变化。

With cystic fibrosis, pancreatic insufficiency results in trypsin and lipase deficits, causing high fecal losses of protein and fats with consequent malnutrition and growth retardation. The stool is voluminous and often foul-smelling. Children who have cystic fibrosis often have respiratory problems and growth failure.

囊性纤维病：胰腺功能不足导致胰蛋白酶和脂酶不足，蛋白质和脂肪随粪便大量丢失，造成营养不良，发育迟滞，大便量多、味臭。有囊性纤维病儿童常常有呼吸道问题和生长不足。

With sugar malabsorption, intestinal mucosal enzymes, such as lactase, which splits lactose to galactose and glucose, may be congenitally absent or temporarily deficient secondary to GI infection. Improvement after eliminating lactose (or other carbohydrates) from the diet or after substituting a lactose-free formula strongly suggests the diagnosis.

糖吸收不良：小肠粘膜酶，如乳糖酶能将乳糖分解成半乳糖和葡萄糖，可能是先天缺失或因胃肠感染引起暂时不足。从饮食中除去乳糖（或其他碳水化合物)或用无乳糖配方替代后症状改善，都有力支持本诊断。

With allergic gastroenteropathy, cow's milk protein may cause diarrhea, often with vomiting and blood in the stools, but intolerance to the carbohydrate fraction of the ingested food should be suspected also. Symptoms often abate promptly when soy formula is substituted for cow's milk and return if cow's milk is reintroduced. Some infants intolerant of cow's milk are also intolerant of soy, so a formula that has had the protein pre-digested and does not contain the offending disaccharide may be needed. Spontaneous improvement usually occurs toward the end of the 1st yr.

过敏性胃肠病：牛奶蛋白可能引起腹泻，通常伴有呕吐和便血，但也应怀疑对摄入食物中的碳水化合物不耐受。用大豆配方替代后症状迅速减轻，但牛奶可使症状再现。有些对牛奶不耐受的婴儿通常对大豆也不耐受，因此，需要一种蛋白预先消化、不含双糖的配方。1周岁时症状会自行改善。

Evaluation

评估

History: History focuses on the quality and frequency of stools as well as accompanying signs and symptoms. Reports of vomiting or fever suggest GI infection. An accurate dietary history is critical. Reports of diarrhea beginning with the introduction of wheat cereal suggest celiac disease. Reports of variation in the stool pattern with certain elements of the diet suggest dietary intolerance. The persistent presence of blood in the stool mandates a careful search for more serious infection or GI disorder.

病史：病史重点是大便质量和频率及伴随症状。呕吐或发烧提示有胃肠感染。准确的饮食史很关键，始于食用小麦类食品引起的腹泻提示有乳糜泻。大便形态各异伴未消化食物提示为饮食不耐受。持续便血就必须深查是否有严重感染或胃肠疾病。

Physical examination: Examination focuses on overall appearance and signs of dehydration, growth parameters, and abdominal findings; poor growth suggests more serious disorders. Pulmonary status is also evaluated in children in whom cystic fibrosis is suspected.

体检：体检重点是总外表和脱水、生长发育、腹部检查症状等。发育不良提示有更严重的疾病。怀疑有囊性纤维化儿童还应作肺部评估。

Testing: Tests are ordered if history and examination suggest a chronic condition. Tests include electrolyte levels if there is dehydration; sweat Cl and Na levels for cystic fibrosis; cultures for viruses, bacteria, or parasites when infection appears to be present; and stool pH for disaccharide intolerance. Levels of certain antibodies are associated with celiac disease. Dietary manipulations can be diagnostic as well as therapeutic.

化验：如病史和体检提示有慢性疾病则应作化验检查。如有脱水，应检查电解质水平；囊性纤维病检查氯和钠水平；如有感染则进行病毒、细菌或寄生虫培养检查；双糖耐受情况检查大便pH值。一定的抗体水平与乳糜泻有关。饮食控制既是诊断性也是治疗性的。

Treatment

治疗

Supportive care for acute diarrhea consists primarily of providing adequate oral (or rarely IV) rehydration. Antimotility agents (eg, loperamide: IMODIUM) are generally not recommended for infants and young children.

急性腹泻的支持护理主要包括足够的口服补水（或IV补液)。抗能动类药（如洛哌丁胺：易蒙停)通常不建议婴儿和幼儿服用。

For chronic diarrhea, adequate nutrition must be maintained, particularly of fat-soluble vitamins. Specific treatments are indicated for certain causes (eg, gluten-free diet for those with celiac disease).

慢性腹泻必须保持营养，尤其是脂溶性维生素。有些病因应采取对症疗法（如乳糜泻病人的无谷胶饮食)。