Normal people usually have a bowel movement once a day, and individuals have 2-3 bowel movements per day or once every 2-3 days, with normal stool properties and an average weight of 150-200g of stool per day, containing 60%-75% of water. Diarrhea (diarrhea) is a common symptom that refers to the frequency of bowel movements significantly exceeding the usual frequency, thin stools, increased moisture, and a daily stool volume of more than 200g, or containing undigested food or pus, blood, or mucus. Diarrhea is often accompanied by a feeling of urgency to defecate, anal discomfort, and incontinence. There are two types of diarrhea: acute and chronic. Acute diarrhea has a rapid onset and lasts for 2 to 3 weeks. Chronic diarrhea refers to recurrent diarrhea with a duration of more than two months or an interval of 2 to 4 weeks.
Etiology
(a) Acute diarrhea The duration of the disease does not exceed 3 weeks, and the most common cause is infection.
1, food poisoning As the food is contaminated with toxins from Staphylococcus aureus, Bacillus cereus, Clostridium perfringens and Clostridium botulinum, it mostly manifests as non-inflammatory watery diarrhea.
2, intestinal infection
(1) viral infection: rotavirus, Norwalk virus, enteric adenovirus infection can occur when the small intestine non-inflammatory non-diarrhea.
(2) bacterial infection: Vibrio cholerae and toxigenic Escherichia coli can cause small intestine non-inflammatory watery diarrhea. Salmonella spp, Shigella spp, Campylobacter spp, Yersinia entcrocolitica, invasive Escherichia coli, Staphylococcus aureus, Vibrio parahaemolyticus, and Clostridium difficile can cause colitis and produce purulent blood diarrhea.
(3) Parasitic infections: Pear-shaped flagellates and Cryptosporidium infections can cause non-inflammatory watery diarrhea of the small intestine. Lyso-enteric ameba invading the colon causes inflammation, ulceration and purulent bloody diarrhea.
(4) Traveler’s diarrhea: It is diarrhea that occurs during or after travel. Most of them are caused by infections, and the pathogens are often toxigenic Escherichia coli, Salmonella, Pear-shaped flagellates, and lyso-organic amebas.
(5) drug-induced diarrhea: laxatives, hypertonic drugs, cholinergic drugs, antibacterial drugs and certain antihypertensive or antiarrhythmic drugs, which do not cause diarrhea during the medication period.
(ii) Chronic diarrhea Chronic diarrhea has a duration of more than 2 months, and its etiology is more complex than acute ones, so diagnosis and treatment are sometimes difficult and are the focus of discussion.
1. Infectious diseases of the intestinal tract
① chronic amoebic dysentery.
② chronic bacterial diseases.
③Intestinal tuberculosis.
④ Pear-shaped flagellosis, schistosomiasis.
⑤ intestinal candidiasis.
2, intestinal non-infectious inflammatory diseases
① inflammatory bowel disease (clonorchiasis and ulcerative colitis)
②Radiation enteritis.
(iii) ischemic colitis.
④diverticulitis.
⑤ uremic enteritis.
3.Neoplasm
①colorectal cancer.
② colon adenomatosis (polyps).
③Malignant lymphoma of the small intestine.
④amine precursor uptake decarboxylation cell tumor (APU-Doma).
gastrinoma, carcinoid tumor, intestinal vasoactive intestinal peptide tumor (VIPoma), etc.
4.Small intestine malabsorption
(1) Primary small intestinal malabsorption.
(2) Secondary small intestinal malabsorption.
Malabsorption.
(1) Pancreatic digestive enzyme deficiency, such as chronic pancreatitis, pancreatic cancer, pancreatic fistula, etc.
(ii) Disaccharidase deficiency, such as lactose intolerance.
③ obstructed bile drainage and insufficient bound bile salts, such as extrahepatic biliary obstruction, intrahepatic bile stasis, small intestinal bacterial overgrowth (blind collaterals syndrome), etc.
Reduced absorption surface of the small intestine.
(i) excessive small bowel resection (short bowel syndrome); (ii) proximal small bowel-colon anastomosis or fistula, etc.
Small intestine infiltrative diseases: Whipple’s disease, α-heavy chain disease, systemic sclerosis, etc.
5.Motor diarrhea
Caused by disturbance of intestinal peristalsis (mostly accelerated), such as irritable bowel syndrome, after major gastrectomy, after vagotomy, partial intestinal obstruction, hyperthyroidism, hypoadrenocorticism, etc.
6, pharmacogenic diarrhea
①Laxatives such as phenolphthalein, senna, etc.
② antibiotics such as lincomycin, clindamycin, neomycin, etc.
③ antihypertensive drugs such as reserpine, guanethidine, etc.
④hepatic encephalopathy drugs such as lactulose, lactosorbide, etc.