Toxic megacolon

　　Toxic megacolon is a complication of severe active colitis. Patients with severe active colitis may develop toxic megacolon primarily due to rapid progression of the disease and improper treatment, or due to errors in the process of insufflation and catheter manipulation during barium enema or fiberoptic colonoscopy for severe active colitis. Potassium deficiency and anticholinergic, antidiarrheal drugs, or opioid analgesics can reduce intestinal muscle tone and inhibit intestinal motility, and may also induce the disease. Due to severe inflammation that destroys the neural and muscular regulatory mechanisms that control the normal intestines, the intraluminal pressure causes the intestinal wall to expand beyond its normal range of movement. In addition, overgrowth of bacteria and the toxins they produce further exacerbate intestinal distension and can lead to peritonitis. The toxicity of bacteria further spreads to the systemic circulation, leading to the production of systemic toxic symptoms.

　　Toxic megacolon involves the entire colon, and the disease can present as segmental lesions, with the transverse colon and splenic flexure being particularly prominent. The pathological changes, in addition to the characteristics of ulcerative colitis and Crohn's disease, mainly manifest as severe inflammation, deep ulcers, crypt abscesses, and pseudopolyps. Due to the rapid expansion of the colon, thinning of the intestinal wall, circulatory disorders, or penetration of intestinal wall abscesses, intestinal perforation is prone to occur.

　　The course of illness from inflammatory bowel disease to toxic megacolon is generally short, with Fazio reporting that about 24% are less than 3 months. Toxic megacolon can also be the initial symptom of inflammatory bowel disease,表现为 high fever, tachycardia, decreased blood pressure, drowsiness, and systemic failure; the abdomen rapidly swells, is tender, presents with tympany on percussion, and has weak or absent bowel sounds, with occasional massive lower gastrointestinal bleeding. When there is tenderness, rebound pain, and muscle tension in the abdomen, it often indicates acute perforation. Laboratory tests show significantly increased total white blood cell count and neutrophil count, left shift, and the presence of toxic granules. Anemia, hypoproteinemia, hypokalemia, hypocalcemia, and hypomagnesemia, as well as dehydration, are common.

　　The abdominal X-ray shows segmental or total colonic dilation, with the transverse colon and splenic flexure being the most obvious. Fazio reported that the diameter of the dilated colon is 5.0-16.0cm, with an average of 9.2cm. In the early stage of toxic megacolon, within a few hours, the colon mesentery at the lower edge of the transverse colon can thicken and then disappear, and a large amount of gas in the stomach and small intestine can be observed at the same time. These symptoms may be caused by gastrointestinal weakness due to intracellular hypokalemia, hypocalcemia, hypophosphatemia, hypomagnesemia, and metabolic alkalosis.

　　1. For patients with recurrent long-term attacks or persistent instability, they should maintain a peaceful and tranquil mood, avoid overexertion, and prevent intestinal infections.
　　2. Pay attention to dietary adjustment, for those with abdominal pain and diarrhea, it is recommended to eat low-fiber, easy-to-digest, low-fat, and high-protein diet; it is best to avoid eating foods that are suspected of being intolerant, such as fish, shrimp, crab, turtle, milk, peanuts, etc.; it is forbidden to eat chili, frozen, and cold food, and to quit smoking and drinking habits.
　　3. Mild patients can continue to work while receiving treatment, while severe and acute patients should rest in bed to reduce intestinal motility and symptoms, and reduce physical consumption.

　　Inflammatory bowel disease patients with severe abdominal pain, a sudden increase in defecation frequency to dozens of times, and bloody mucus-like stools should be vigilant for the occurrence of toxic megacolon. If the abdominal X-ray shows that the transverse colon lumen diameter is greater than 6cm, it can be diagnosed.

　　Some people believe that abnormal accumulation of gas in the small intestine is an early symptom of toxic megacolon, but persistent small intestinal gas and severe metabolic alkalosis make patients with severe inflammatory bowel disease prone to develop toxic megacolon, manifested as body temperature > 38.6°C, heart rate > 120 beats per minute, significantly increased blood leukocytes, anemia, accompanied by consciousness disturbance, decreased blood pressure, dehydration, and electrolyte imbalance.

　　Therefore, the early diagnosis of this condition relies on strict clinical observation, abdominal X-ray, and the understanding of the condition. When the medical history is unclear or toxic megacolon is the first symptom, it is necessary to differentiate it from toxic megacolon caused by bacterial dysentery, amebic dysentery, typhoid fever, cholera, pseudomembranous colitis, ischemic colitis, diverticulitis, and other conditions.

　　1. In addition to avoiding catching a cold and controlling emotions, diet is also a very important aspect. For those with abdominal pain and diarrhea, it is recommended to eat low-fiber, easy-to-digest, low-fat, and high-protein diet; it is best to avoid eating foods that are suspected of being intolerant, such as fish, shrimp, crab, turtle, milk, peanuts, etc.; it is forbidden to eat chili, frozen, and cold food, and to quit smoking and drinking habits

　　2. Pay attention to food hygiene, do not eat raw, cold, hard, or deteriorated food, and avoid alcohol and spicy and strong刺激性 spices.

　　3. Patients should strengthen their physical exercise in their daily life, such as practicing Tai Chi, to strengthen the lumbar and kidney, and enhance their physique.

　　4. Pay attention to keeping the abdomen warm.

　　The traditional Chinese medicine differentiation and treatment of toxic megacolon is as follows:

　　1 Spleen and Stomach Weakness Syndrome: Symptoms include loose stools, recurrent attacks, loss of appetite, abdominal pain, intestinal rumbling, abdominal distension, increased frequency of stools after eating greasy food, stool often mixed with mucus and a small amount of pus, yellowish face, pale tongue with white coating, weak and slow pulse.

　　Analysis of symptoms: The spleen and stomach are the root of postnatal life, responsible for the digestion and transformation of food and drink. If damaged, the spleen and stomach Yang deficiency, food and drink not transformed, dampness and wetness accumulate, descend to the large intestine, leading to congestion, edema, and ulcers in the large intestine.

　　Treatment method: Invigorate the middle-jiao and strengthen the spleen, harmonize the stomach and stop diarrhea.

　　Herbal formula: Modified Shen Ling Bai Zhu Powder. This formula has the effects of replenishing Qi, invigorating the spleen, and draining dampness to harmonize the stomach. In this formula, Ren Shen, Bai Zhu, Fu Ling, and Gan Cao invigorate the spleen and Qi; Sha Ren, Chen Pi, Jie Geng, Bie Dou, Shan Yao, Lian Rou, Yi Yi Ren regulate Qi, invigorate the spleen, and transform dampness. If the illness persists for a long time without recovery, with Qi sinking, prolonged diarrhea, treat with Bu Zhong Yi Qi Pill; if the spleen and stomach are weakened, with internal cold causing abdominal cold pain, cold limbs, diarrhea, use Modified Guizhi Ren Shen Decoction to warm the middle-jiao and disperse cold, combine with Ping Wei San for dampness, with Xiang Lian Wan for heat, and with Fuzi Li Zhong Wan for internal excess of Yin cold to warm the middle-jiao and disperse cold.

　　2 Large Intestine Damp-Heat Syndrome: Symptoms include severe illness, abdominal pain with diarrhea, diarrhea as if pouring, foul-smelling blood stool. Or watery diarrhea and purulent blood stool, abdominal distension, intestinal rumbling, burning and painful anal area. Or accompanied by chills, restlessness, dry mouth without desire for drinking, loss of appetite, short and red urine, yellow greasy tongue coating, slippery rapid pulse.

　　Analysis of symptoms: The patient has insufficient spleen and stomach, with impaired spleen function, internal accumulation of dampness and wet obstruction of the spleen, leading to heat transformation, damp-heat accumulation in the large intestine, resulting in this condition. Damp-heat moving downward to the large intestine leads to dysfunction of the conveying function, intermingling of damp-heat, obstruction of the intestines and stomach, and adverse flow of Qi, causing abdominal pain and diarrhea; severe heat and accumulated dampness scorch the intestines, damaging the collaterals, corroding the mucosa, resulting in stool with red and white sticky mucus or even bloody stool; acute and sudden diarrhea with burning anal pain, purulent mucus, or accompanied by urgent defecation; damp-heat pathogen damaging the vital Qi, bleeding in the blood, purulent stool in the Qi, and when both Qi and blood are damaged, purulent and bloody stool appear. Dampness is a Yin pathogen, sticky in nature, which may be accompanied by symptoms such as body weightiness, fatigue, loss of appetite, etc. Excessive heat and injury to body fluid lead to dry mouth, and the retention of dampness leads to dry mouth without desire for drinking. Diarrhea and injury to body fluid lead to insufficient source of transformation, resulting in short and dark urine. Yellow greasy tongue coating and slippery rapid pulse are signs of internal excessive damp-heat.

　　Treatment method: Clear heat and drain dampness.

　　Herbal formula: Modified Gan Guan Qin Lian Decoction. This formula focuses on clearing damp-heat in the intestines, raising the clear and lowering the turbid to stop diarrhea. The herb Gegen is decocted to mainly relieve muscular aches and reduce fever, as well as to raise the clear and stop diarrhea; Huang Qin and Huang Lian clear heat, detoxify, and dry dampness to lower the turbid; Gan Cao harmonizes the middle and relieves pain. For those with severe fever, add Yin Hua, Gong Ying, and Chai Hu; for summer heat invasion, add Li Yi San to clear heat and resolve summer-heat, promote diuresis and stop diarrhea; if dampness is predominant, with chest and hypochondrium stuffiness, aversion to drinking, white greasy tongue coating, add Huoxiang, Peilan, Cang Zhu, Bai Kui Ren; for both dampness and heat, with fever, thirst for cold drinks, thick yellow tongue coating, add Jin Yin Hua, Bai Tou Weng, Qin Pi, Ma Chi Xian, raw Da Huang, etc.; for those with nausea and vomiting, add Ban Xia, Chen Pi, Jiang Zhu Ru; for those with hematochezia, use Dang Gui, Chi Xao, Chi Xiao Dou, Qin Pi, etc., to nourish blood and remove dampness, clear heat and detoxify, or use Huai Hua, Di Yu to cool blood and stop bleeding, Fang Feng, stir-fried Jing Jie to clear the wind in the blood, or add San Qi powder, Yunnan Bai Yao to resolve blood stasis, generate new blood, and stop bleeding, and add Bai Ji powder to assist in tissue growth and bleeding.

　　3 Severe Heat-toxin Syndrome: Clinical manifestations include rapid onset, persistent high fever, thirst, irritability, discomfort in the chest, nausea and vomiting, severe abdominal pain, urgency, purulent stools, large amounts of purple and red blood, or in the form of blood and water, frequent stools, a red and deep tongue, a yellow and dry coating, a slippery and rapid pulse, and even coma and convulsions.

　　Analysis of Syndrome: The trend of toxic heat is fierce, so the disease is acute. Heat binding to the Yangming meridian leads to consumption of body fluid, causing high fever and thirst; heat disturbing the mind leads to restlessness and irritability; toxic heat attacking the spleen and stomach leads to discomfort in the chest and nausea and vomiting; toxic heat is severe, causing blood stasis, intestinal obstruction, undescending turbid qi, leading to abdominal pain and urgency; toxic heat intertwining and consuming Qi and blood, turning into purple and red sputum and blood, or heat damaging the collateral vessels, causing sudden copious and forceful stools in the form of blood and water; a red and deep tongue, a yellow and dry coating, and a slippery and rapid pulse are all signs of severe toxic heat. If the toxic heat invades the heart's nutritive Qi, obstructing the spirit, confusion and delirium may occur; extreme heat generates wind, leading to internal movement of the liver wind, resulting in convulsions. Treatment: Clear heat and detoxify, cool blood and stop bleeding.

　　Prescription: Modified Bai Tou Weng Decoction and Huang Lian Jie Du Decoction. They work together to clear heat, cool blood, detoxify and calm the mind. In the prescription, Bai Tou Weng clears heat and relieves dampness, eliminates the toxic evil in the blood; combined with Huang Lian, Huang Qin, Huang Bai, and Zhi Mu, it detoxifies and cools blood, promotes blood circulation; Da Huang guides heat downwards, expels toxins and evil, cleanses the toxic heat in the large intestine; Sheng Shi Gao clears and cools the heat in the qi aspect. If there is severe heat-toxin burning, spreading to the nutrient and blood, with high fever, confusion, and delirium, take Zi Xue Dan or An Gong Niu Huang Wan 2-3g to clear heat and expel toxins, open the orifices and醒神; if there is high fever, convulsions, and spasms, add Zi Xue San 2g, Quan She 10g, Gou Teng 15g to clear the liver, stop wind, and calm; if there is frequent vomiting, consumption of stomach Yin, with a red and dry tongue, add 12g of American ginseng, 30g of Mai Dong, 15g of Shi Hu to nourish the stomach Yin; if there is persistent vomiting, take Yu Zhu Dan for oral administration to harmonize and stop vomiting; if there is excessive diarrhea, with difficulty in taking food and water, or coldness in the limbs, pale complexion, cold sweat, and shortness of breath, it is due to internal closure of toxic heat and external loss of Yang, take Dushen decoction or Ren Shen Si Ni decoction for concentrated decoction and immediate administration to invigorate Qi and secure the Yin.

　　Traditional Chinese Medicine Treatment

　　1 Compound Xianhecao Enteritis Capsule: Take orally, three times a day, 1.2g each time. This product has the effects of clearing heat and drying dampness, invigorating the spleen and stopping diarrhea. It is suitable for syndrome of internal damp-heat.

　　2 Shenshen Bai Shu Granule: Dissolve in boiling water for oral administration, three times a day, 3g each time. This product has the effects of invigorating the spleen and stomach, harmonizing the stomach and transforming dampness. It is suitable for syndrome of spleen deficiency with dampness.