Melena is black tarry stools that are formed during heavy (more than 60 ml) acute or chronic bleeding from different parts of the gastrointestinal tract. The cause of the pathological condition may be primary lesions of the digestive system, violations of the hemostasis system, some infectious diseases. In order to detect the source and cause of hemorrhage, endoscopic, radiological and laboratory research methods are used. With a characteristic change in the appearance of feces, you should immediately consult a doctor.
general characteristics
In the case of the development of melena, the patient notices a sharp change in the consistency and color of the feces - they become more liquid, "sticky", turn black (tarry stools). It is necessary to distinguish between melena and physiological changes in the color of feces due to medication - feces after the use of iron and bismuth preparations are formed, solid. Bleeding is accompanied by abdominal pain of varying intensity and other dyspeptic disorders, the severity of which depends on the level and degree of damage to the digestive system.
In some cases, with the appearance of blood in the feces, the pain syndrome subsides. Simultaneously with the onset of melena, vomiting of “coffee grounds” develops, general well-being is disturbed: the skin and mucous membranes become pale, dizziness, weakness, and fainting are noted. With massive blood loss, collapse is possible, which is characterized by a frequent weak pulse, a sharp drop in blood pressure, and loss of consciousness. Bleeding from the gastrointestinal tract is a symptom of serious pathological conditions and requires emergency qualified medical care.
Causes of melena
Most often, heavy bleeding, leading to the release of black tarry feces from the rectum, complicates the course of gastroduodenal pathology. A more rare factor causing the development of melena are abundant nasal and pulmonary hemorrhages, accompanied by the ingestion of blood. Violation of the color and consistency of feces is observed in acute erosive esophagitis, periarteritis nodosa, which occurs with the involvement of small vessels of the gastrointestinal tract in the process. Altered blood that appears in the stool in the general serious condition of the patient may indicate a rupture of the aortic aneurysm into the lumen of the small intestine.
Gastrointestinal bleeding
The main cause of melena is the development of acute or profuse chronic hemorrhages from the upper segments of the gastrointestinal tract, associated mainly with ulcerative-destructive processes in the mucous membrane. The dark color of feces appears when whole blood interacts with hydrochloric acid of the stomach and the conversion of hemoglobin into hematin hydrochloride. The appearance of melena is also caused by bleeding from the small or initial sections of the large intestine, subject to a slowdown in peristalsis and a violation of the passage of feces. Tar-like stools are a symptom of gastrointestinal diseases such as:
- Gastritis . Melena is often found in the erosive variant of acute gastritis, which is manifested by extensive superficial lesions of the mucous membrane of the organ. Bleeding occurs against the background of severe pain in the epigastric region, nausea and vomiting, changes in the nature and frequency of stools. The condition develops after poisoning with chemicals, taking drugs that irritate the mucous membrane.
- Ulcer disease . With a deep lesion by the ulcerative process of the wall of the stomach or duodenum, the vessels are destroyed, hemorrhage occurs. Bleeding can be minor or massive with signs of melena. A pathognomonic sign indicating the presence of an ulcer is a decrease or complete disappearance of the pain syndrome after the onset of hemorrhage.
- Mallory-Weiss syndrome . A detailed clinical picture of the disorder often develops against the background of recurrent vomiting, intense coughing, and indomitable hiccups. For the disease, repeated vomiting with impurities of scarlet blood is more characteristic, but sometimes blood accumulates in the stomach and is destroyed by hydrochloric acid, which causes the appearance of tarry stools 6-8 hours after the first symptoms.
- Cancer of the stomach . For tumors of the stomach, the combination of coffee grounds vomiting and melena is pathognomonic. The condition appears in the later stages of neoplasm development, when the tumor tissue grows deep into the wall of the organ and destroys the blood vessels. Typical is a persistent pain syndrome, frequent nausea, vomiting after eating, symptoms of cancer intoxication (weight loss, general weakness, lack of appetite).
- Erosive bulbitis . Hemorrhage and melena are more often observed in the acute variant of the lesion of the duodenal bulb. Other symptoms - dull epigastric pain, periodic nausea and vomiting, stool instability with a tendency to constipation - are of little specificity and occur with any lesions of the upper digestive system. Bleeding can be provoked by chemical damage, taking NSAIDs.
- Occlusion of the mesenteric arteries . Due to thrombosis and vascular embolism, there is a sharp cessation of the blood supply to the intestine with ischemic and destructive changes in its wall. The first sign of occlusion is severe abdominal pain, accompanied by reflex repeated vomiting with bile impurities. The color and texture of the feces change several hours after the onset of symptoms.
- Necrotizing enterocolitis of newborns . The disease manifests itself mainly in premature babies 1-2 weeks after birth. Melena develops as a result of extensive ischemic and necrotic changes in the intestinal wall due to intrauterine hypoxia or asphyxia during childbirth. The disease is very difficult, bleeding from the gastrointestinal tract is complicated by DIC, multiple organ failure.
Infectious pathologies
Melena in viral or bacterial lesions is potentiated both by the direct action of microorganisms on the walls of the digestive tract, and by indirect influence through disturbances in the mechanisms of vascular permeability and hemostasis. The appearance of black fetid feces is accompanied by a general infectious syndrome: febrile fever, headaches, myalgia and arthralgia. Gradually develop pathognomonic symptoms for each pathogen. Of the infectious diseases, chalk is most often complicated by:
- Hemorrhagic fever . Viral damage to the organs of the reticuloendothelial system causes a pronounced lack of platelets, which, combined with pathological changes in the vascular wall, provokes melena, hematuria, nosebleeds. In addition to the allocation of black feces, a hemorrhagic rash on the skin and mucous membranes is determined. In severe situations, hypovolemic shock may develop.
- Typhoid fever . At the stage of necrotic changes and cleansing of typhoid ulcers of the intestine, bleeding from damaged intestinal arteries may occur. Such a complication usually occurs at 3-4 weeks of typhoid fever with a typical staging of the process. Also characteristic is a discrepancy between changes in the pulse and the degree of increase in body temperature - heart rate of normal frequency with high febrile fever.
- Dengue fever . Melena is detected in the hemorrhagic form of the infectious process. At the initial stages, patients complain of fever, malaise. Spontaneous bleeding from the digestive tract occurs 2-3 days after the onset of symptoms, due to the predominant lesion of the capillaries in combination with changes in the rheological properties of the blood, a decrease in the number of coagulation factors.
Blood clotting disorders
Hemorrhage in the upper parts of the digestive tract may be associated with systemic hematological diseases, which develop a tendency to hypocoagulation, insufficiency of coagulation factors, and a pathological increase in the permeability of the vascular wall. In such diseases, melena is accompanied by nasal, uterine and pulmonary bleeding. Hemorrhages in the cavity of the joints and pericardium are possible, which leads to the appearance of the corresponding symptoms. The main causes of tarry stools are the following hemorrhagic diseases:
- Hemophilia . Massive bleeding, manifested by melena, is observed in moderate and severe forms of pathology, in which the level of clotting factors is not more than 5% of the norm. In most cases, the manifestation of hemophilia occurs in early childhood. The main symptom, which occurs in 80% of patients, is hemorrhages in the joint cavity, extensive hematomas after impact, hematuria are also characteristic.
- Rendu-Osler-Weber disease . Blood staining of the feces indicates a severe course of the process with diffuse damage to the small vessels of the digestive tract. With this disease, in addition to melena, nosebleeds often begin for no reason, which are extremely difficult to stop. A characteristic feature is hemorrhagic telangiectasia on the skin of the face, mucous membrane of the lips and cheeks.
- thrombocytopenia . The hemorrhagic syndrome is provoked by a sharp decrease in the number of platelets, which may be of an autoimmune nature or develop secondary to other hematological disorders. Patients complain of the causeless appearance of bruises and bruises, bleeding from the nasal passages. For thrombocytopenia, a combination of melena and pain in the left hypochondrium is typical, which is due to an increase in the spleen.
Liver pathology
The cause of gastric bleeding with the release of black "sticky" stools are chronic liver diseases (fibrosis, cirrhosis), leading to portal hypertension. Due to a violation of the outflow of blood, the collateral vessels of the lower third of the esophagus and stomach expand, and then rupture with an increase in pressure in the abdominal cavity, which is accompanied by massive blood loss. In primary lesions of the liver, melena, as a rule, is combined with hematemesis, specific “liver signs”: palmar erythema, spider veins on the skin of the abdomen.
Survey
The patient is examined by a gastroenterologist, in case of massive hemorrhage, a consultation with a surgeon is required. Diagnostic search in the presence of melena is aimed at the rapid detection of the source of bleeding, and, if possible, its elimination. A complex of instrumental and laboratory methods is used, which are necessary to study the state of the digestive tract, assess the severity of the patient's condition and the degree of hemodynamic disorders. The most valuable for diagnosis are:
- X-ray examination . A series of radiographs with oral contrasting of the gastrointestinal tract with barium sulfate is an alternative to the endoscopic examination method. With the help of radiography in 80-85% of cases it is possible to determine the localization of damage, but the technique is not always informative for establishing the etiology.
- Endoscopy . EGDS using a flexible probe is used not only to detect the site of hemorrhage, but also as a therapeutic method - special tools allow you to "burn" a bleeding vessel. In doubtful cases, to verify the causes of melena, a biopsy of the altered sections of the mucosa is performed.
- Fecal analysis . In order to confirm the presence of blood in the feces, a triple Gregersen reaction is performed, which reveals even a small amount of blood pigments. Be sure to perform a standard coprogram, according to indications, a bacteriological examination of feces is prescribed.
- Coagulogram. The results of the analysis of clotting ability, activity of the internal and external links of hemostasis are indicative of suspected hereditary hemorrhagic pathologies with clotting disorders. To control the dynamics of the patient's condition, the study is done several times.
- Studies of blood parameters . All patients with melena are recommended a complete blood count, which provides an approximate assessment of the degree of blood loss for the development of further treatment tactics. To exclude concomitant diseases, a biochemical blood test, liver tests are necessary.
In case of massive bleeding and the impossibility of conducting a qualitative endoscopic examination, selective mesenteric arteriography is prescribed to visualize the exact site of damage to the vessel. Radionuclide scanning with labeled erythrocytes is used as a screening test for unclear etiology of melena.
To detect traces of blood in the feces, a stool test for occult blood is prescribed.
Symptomatic therapy
Melena is a specific sign of profuse bleeding from the vessels of the digestive organs. Such a pathological condition cannot be eliminated independently at home. With the appearance of tarry dark feces, it is necessary to immediately seek qualified medical help, since untimely diagnosis and treatment are fraught with massive blood loss, severe disturbances in the activity of all body systems.