The causes of blood in the stool are different, and how to evaluate and diagnose the treatment is explained in this article (2023)

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Written | Chen Chen's
blood in the stool is one of the common symptoms of
patients presenting to the gastroenterology department.
The etiology of blood in the stool is complex and changeable, and it is a key
point for clinicians to grasp.
The color of blood in the stool may vary depending on the site of the bleeding, the amount of bleeding, and the length of time the blood stays in the bowel lumen, and may be bright red, dark red, or black
A small amount of bleeding (within 5~10ml) does not cause the color of the feces to change, and it can be determined
by occult blood test.

hematochezia is mostly caused by digestive diseases, including lower and upper gastrointestinal diseases, and can also be local manifestations of systemic diseases, such as liver and kidney dysfunction, blood system, infectious diseases, connective tissue diseases, etc.
involving the digestive tract

Lower gastrointestinal diseases
(1) colorectal:
(1) Common causes: colon tumors, colon polyps, acute infectious enteritis, ischemic colitis, hemorrhoids, fissures, fistulas, colonic diverticular disease, colonic ulcerative lesions, colon lesions, postoperative bleeding from surgery or endoscopic treatment, etc
In recent years, taking non-steroidal anti-inflammatory drugs, aspirin or other antiplatelet drugs, and anticoagulant drugs has gradually become an important cause of
colorectal bleeding.

(2) Rare causes: colonic vascular malformation, Dieulafoy disease, radiation enteritis, isolated rectal ulcer, physical and chemical injury, etc

(2) Small intestine: (1) Common causes:
inflammatory bowel disease (Crohn's disease), tumor, Meckel diverticulum, Dieulafoy disease, vascular malformation, ischemic bowel disease, NSAID-associated ulcers, stress ulcers, polyposis syndromes, etc

(2) Rare causes: Henoch-Schรถnlein purpura, small intestinal vascular malformation and/or combined portal hypertension, intestinal bacteria/parasitic infection, intussusception, amyloidosis, blue rubber blister nevus syndrome, vascular intestinal fistula and Kaposi sarcoma

upper gastrointestinal diseases
(1) stomach, duodenum: peptic ulcer, acute erosive hemorrhagic gastritis, Gastric cancer, gastrinoma, Dieulafoy disease, lymphoma, gastric polyps, etc

(2) Esophagus: reflux esophagitis, esophageal diverticulitis, esophageal cancer, esophageal foreign body, esophageal cardia mucosal tear syndrome, etc

(3) Esophageal and gastric varices or portal hypertension gastropathy bleeding
caused by portal hypertension 3
systemic diseases
Leukemia, thrombocytopenic purpura, hemophilia, hereditary telangiectasia, vitamin C and vitamin K deficiency, severe liver disease, uremia, epidemic hemorrhagic fever, sepsis, etc

-2-Initial evaluation and judgment
of hematochezia is mostly lower gastrointestinal bleeding, which can be manifested as acute major bleeding, chronic minor bleeding, and intermittent bleeding
The severity of bleeding, possible sites, and causes
of bleeding should be assessed first.

Assess bleeding severity
: Signs of peripheral circulatory failure suggest large blood loss
ใ€‚ The shock index (heart rate/systolic blood pressure) is an important indicator
of blood loss.
The study found that the following factors may be related to poor prognosis of patients: hemodynamic instability, persistent bleeding, age greater than 60 years, more comorbidities, elevated serum creatinine, and severe anemia, etc.
, the more high-risk risk factors, the more serious the disease, and the need for more aggressive rescue treatment

Patients with chronic small bleeding are often overlooked, and may be seen in other departments due to dizziness, fatigue, palpitations, and pallor

Determine the possible bleeding site and cause, the color of blood in the stool can vary depending on the bleeding site,
The amount of bleeding varies by how long the blood stays in the bowel lumen
If the amount of bleeding is large and fast, it is bright red; The amount of bleeding is small, slow, and the blood stays in the intestine for a long time, which can make the stool appear dark red or black.

Generally speaking, if the amount of blood is large, the feces are small, and the blood and feces are mixed evenly, indicating that the gastrointestinal bleeding is higher, and the small intestinal bleeding below the ligament of Flex is mostly dark red blood
Anorectal lesions are mostly bright red bloody stools, most of which do not mix with feces and attach to the surface of feces, or drip blood
after stool.

During the initial clinical evaluation, a detailed medical history should be taken, including the characteristics of blood in the stool (color, whether it is formed, whether there is pus, etc.
), duration, frequency and amount, as well as accompanying symptoms such as abdominal pain, abdominal distension, fever, weight loss, dizziness, palpitations, etc.
; At the same time, the patient's previous surgical history, abdomen-pelvic radiation therapy history, and medication status, such as non-steroidal anti-inflammatory drugs, antiplatelet drugs and anticoagulant drugs, etc
Physical examination such as abdominal signs, mucocutaneous membranes, and digital examination can also provide clues
to the diagnosis.
Complete laboratory tests, including blood routine, blood group, blood coagulation routine, stool routine, liver and kidney function, electrolytes, and tumor markers
In patients with hematochezia who cannot exclude upper GI bleeding, gastroscopy should be done before colonoscopy to determine the presence of upper GI bleeding

-3-The basic management principles of gastrointestinal bleeding under the diagnosis and treatment process
are rapid assessment, hemodynamic stability, localization and qualitative diagnosis, and treatment
as needed.
Treatment measures include supportive care, medication, endoscopic therapy, vascular embolization and surgical treatment

If it is colorectal bleeding, commonly used hemostatic drugs include somatostatin, posterior pituitary hormone, snake venom hemocoagulase, norepinephrine, etc.
, which have a certain effect on small intestinal hemorrhagic somatostatin and thalidomide, but the efficacy of drug hemostasis needs to be verified by further clinical studies, and attention should be paid to whether there are contraindications
For patients considering upper gastrointestinal bleeding, there is more evidence to support the use of proton pump inhibitors

According to the "Guidelines for the Diagnosis and Treatment of Lower Gastrointestinal Bleeding" issued by the Chinese Medical Association in 2020, it is aimed at patients considering colorectal bleeding, you can refer to the following diagnosis and treatment process (Figure 1):
Figure 1 Colorectal bleeding diagnosis and treatment process Small intestinal bleeding symptoms are usually more insidious and lack specificity, and the small intestine has anatomical characteristics such as long length, complex arrangement, and large range of motion in the abdominal cavity, which are difficult to fully explore by conventional gastroscopy and
colonoscopy , the diagnosis of small bowel bleeding is still very difficult, and the rate of missed diagnosis and misdiagnosis is high
The diagnosis and treatment process can be referred to Figure 2

Figure 2 Summary of the diagnosis and treatment process
of small intestinal bleeding:
blood in the stool can be caused by digestive diseases.
May also be a manifestation of
systemic disease.
According to the characteristics of blood in the stool, accompanying symptoms and related medical history, the location and cause of bleeding can be preliminarily judged
Qualitative diagnosis should be determined and appropriate medical, endoscopic, interventional, or surgical treatment
should be selected in combination with relevant examinations under the premise of hemodynamic stability.

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๐Ÿ‘‡๐Ÿ‘‡๐Ÿ‘‡ References: [1] Colorectology Group, Digestive Endoscopy Branch of Chinese Medical Association, Colorectal Group of Gastroenterologist Branch of Chinese Medical Doctor Association, National Clinical Research Center for Digestive Diseases.
Guidelines for the diagnosis and treatment of lower gastrointestinal bleeding (2020)[J].
Chinese Journal of Digestive Endoscopy,2020,37(10):685-695.
[2]Triantafyllou K,Gkolfakis P,Gralnek I M,et al.
Diagnosis and management of acute lower gastrointestinal bleeding:European Society of Gastrointestinal Endoscopy(ESGE)Guideline[J].
[3] Emergency Physician Branch of Chinese Medical Doctor Association, Emergency Medicine Branch of Chinese Medical Association, All-Army Emergency Medicine Professional Committee, etc.
Expert consensus on the emergency diagnosis and treatment process of acute upper gastrointestinal bleeding[J].
Chinese Journal of Emergency Medicine,2021,41(1):1-10.

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This article reviewed: Yang Health Deputy Chief Physician of Jingdezhen Second People's Hospital Responsible Editor: Wen Jiaxin
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