Original: Fu Chong digestion time
Blood, urine, and stool tests are usually called the "three major routines." Routine stool examination has certain application value in the diagnosis of intestinal infectious diseases, intestinal parasitic diseases, the digestion and absorption function of the gastrointestinal tract and accessory glands, the screening examination of gastrointestinal tumors, and the diagnosis and identification of jaundice. Regarding routine stool examinations, the gastroenterologist must master the following 5 points.
What does a normal person's feces look like?
Normal people usually have a bowel movement once a day, with an amount of 100 to 300 g, which varies with the amount of food consumed, the type of food, and the functional state of the digestive organs. Those who eat fine grains and meat-based foods will have fine and small stools. Those who eat coarse grains and eat more vegetables will increase the amount of feces due to more fiber. The stool of a normal adult is yellowish-brown cylindrical soft stool when it is discharged, and the stool of a baby is yellow or golden yellow mushy stool. After prolonged storage, the color may darken due to the oxidation of porphobilinogen in the stool. Normal feces have a foul smell due to protein decomposition products, which are heavy for meat eaters and light for vegetarians.
What should I pay attention to when sending stool?
Use clean bamboo sticks or wood chips to collect a large piece of fresh feces of broad beans, put them in a cardboard box for specimens, write their names, and send them for inspection immediately. If there is pus and blood in the stool, the pus and blood should be collected, and the water sample should be kept in a container. When checking for parasites, keep a little in each part of the stool. No need to fast for meat and vegetables.
What is the principle of fecal occult blood test?
The CFOBT method uses the heme of hemoglobin to have weak peroxidase activity, which allows hydrogen peroxide to release new oxygen to oxidize and develop color reagents (pilami holes, etc.), thereby indirectly identifying and judging small amounts of gastrointestinal tract Bleeding. This method has poor specificity, is easily affected by factors such as meat, green leafy vegetables, iron and other factors in the food, and has low sensitivity. It can only show positive when the gastrointestinal bleeding reaches 4 to 5 ml/d.
The mechanism of IFOBT is the combination of specific antibodies with the complete globulin in hemoglobin in human feces. The result is not affected by factors such as diet, drugs and animal hemoglobin, so the false positive rate is low. The false negatives are mainly related to hemoglobin degradation and storage. The time is too long. However, the above factors can be avoided as long as the submitted specimens are detected in time.
Therefore, the immunoassay has high sensitivity when detecting colonic bleeding, and can detect bleeding volume of 0.3 mL/d. The chemical method requires 5 mL/d of bleeding.
For bleeding caused by upper gastrointestinal diseases, hemoglobin has been partially degraded into porphyrin and hemoglobin when passing through the stomach, duodenum, and small intestine, and part of the globulin has also begun to degrade. Therefore, intact hemoglobin appears in the stool The probability is reduced.
How does the mucus in the stool come from?
Under normal circumstances, there is a small amount of mucus in the stool, but because it mixes evenly with the stool, it is invisible to the naked eye. In pathological conditions, mucus may increase the most, so if there is visible mucus, it should be considered abnormal. In enteritis, the increased mucus is evenly mixed in the stool; in the case of colitis, since the stool has gradually formed, the mucus is not easily mixed with the stool; the mucus from the rectum is attached to the surface of the stool; the mucus in the simple mucus stool It is transparent and slightly viscous; purulent mucus is yellow-white and opaque.
How to identify diseases based on stool?
When abnormal stool is found through visual inspection, early detection and early treatment of the disease can be achieved. Visual inspection includes identifying color and identifying traits;
1. Color recognition
(1) Normal stool is yellowish brown (due to fecal bilinin).
(2) The colors that can appear when the stool is abnormal are:
Light yellow: more common in baby stools, indicating indigestion of fat.
Green: Stool appears green when children have diarrhea, but it can also appear green when adults eat a lot of green foods such as spinach.
Grayish white: common in biliary obstructive diseases, such as cholecystitis, biliary calculi, biliary tumors, biliary parasites, etc.; when the biliary tract is blocked, bile cannot be discharged into the intestine, which reduces the production of fecal bilinin, resulting in the loss of yellow stool and grayish white After eating a lot of fat, or barium meal fluoroscopy, it can also be off-white.
Jam color: common in acute amoebic dysentery; too much mulberry and animal blood products can also be jam-colored.
Red: mostly caused by bleeding in the lower part of the intestine, such as colorectal cancer, acute dysentery, and hemorrhoids. But hemorrhoids; bleeding is more common at the end of the stool, acute dysentery stool is pus and blood, that is, blood in the pus. If you eat a lot of tomatoes, they can also be red.
Black coal burnt color: can be caused by heavy bleeding in the upper intestine. Such as gastric ulcer bleeding, ruptured esophageal and gastric varices caused by liver cirrhosis, gastrointestinal malignant tumors, etc.
(1) Normal human stool is columnar and soft.
(2) Certain diseases can cause changes in stool characteristics:
Flat ribbon stool: seen in rectal or pyloric stenosis. For example, when suffering from rectal cancer, the stool becomes thin, flat or unshaped. Some excrete mucus, often misdiagnosed as enteritis or dysentery.
Spherical hard stool: It can appear when constipation.
Mucous stool: Sometimes there is a very small amount of mucus on the surface of normal stool. If a large amount of mucus appears, it can be seen when the intestinal wall is irritated or inflamed. Such as enteritis, dysentery and acute schistosomiasis. When suffering from acute enteritis, the stool volume is large, watery, may contain a small amount of mucus, and has a foul smell.
Purulent mucus and blood in stool: more common in dysentery. The stool is mixed with a lot of pus and blood, and the mucus is bright red, off-white or gray-red, viscous-like, without special smell.
Sauce-colored mucous stool: It is more common in protozoa. The stool contains blood and mucus. It often coexists with the stool without mixing, and has a rancid smell.
Watery stool: It can be seen in indigestion or diarrhea caused by intestinal trichomoniasis. If it is accompanied by mucus, pus, and blood, it can be seen in acute enteritis;
Congeal serous stool: more common in cholera, paracholera, etc.
Foamy or egg-drop soup-like stools: more common in infants with indigestion, due to indigestion of fat or casein.