Melena

A common sign of upper GI bleeding, melena is the passage of black, tarry stools containing digested blood. The characteristic color results from bacterial degradation and hydrochloric acid acting on the blood as it travels through the GI tract. At least 60 ml of blood in the GI tract is needed to produce this sign. (See Comparing melena with hematochezia.)

Severe melena can signal acute bleeding and life-threatening hypovolemic shock. Usually, melena indicates bleeding from the esophagus, stomach, or duodenum, although it can also indicate bleeding from the jejunum, ileum, or ascending colon. This sign can also result from swallowing blood, as in epistaxis; from taking certain drugs; or from ingesting alcohol. Because false melena may be caused by ingestion of lead, iron, bismuth, or licorice (which produces black stools without the presence of blood), all black stools should be tested for occult blood.

Action stat!

If the patient is experiencing severe melena, quickly take his orthostatic vital signs to detect hypovolemic shock. A decline of 10 mm Hg or more in systolic pressure or an increase of 10 beats/minute or more in the pulse rate indicates volume depletion. Quickly examine the patient for other signs of shock, such as tachycardia, tachypnea, and cool, clammy skin. Insert a large-bore I.V. catheter to administer replacement fluids and allow for blood transfusion. Obtain hematocrit, prothrombin time, International Normalized Ratio levels, and partial thromboplastin time. Place the patient flat with his feet elevated. Administer supplemental oxygen as needed.

History and physical examination

If the patient's condition permits, ask when he discovered that his stools were black and tarry. Ask about the frequency and quantity of bowel movements. Has he had melena before? Ask about other signs and symptoms, notably hematemesis or hematochezia, and about use of anti-inflammatories, alcohol, or other GI irritants. Also, find out if he has a history of GI lesions. Ask if the patient takes iron supplements, which may also cause black stools. Obtain a drug history, noting the use of warfarin or other anticoagulants.

Next, inspect the patient's mouth and nasopharynx for evidence of bleeding. Perform an abdominal examination that includes inspection, auscultation, palpation, and percussion. Then perform a rectal examination.

Medical causes

Colon cancer.On the right side of the colon, early tumor growth may cause melena accompanied by abdominal aching, pressure, or cramps. As the disease progresses, the patient develops weakness, fatigue, and anemia. Eventually, he also experiences diarrhea or obstipation, anorexia, weight loss, vomiting, and other signs and symptoms of intestinal obstruction.

With a tumor on the left side of the colon, melena is a rare sign until late in the disease. Early tumor growth commonly causes rectal bleeding with intermittent abdominal fullness or cramping and rectal pressure. As the disease progresses, the patient may develop obstipation, diarrhea, or pencil-shaped stools. At this stage, bleeding from the colon is signaled by melena or bloody stools.

Ebola virus.Melena, hematemesis, and bleeding from the nose, gums, and vagina may occur later with Ebola virus. Patients usually report an abrupt onset of headache, malaise, myalgia, high fever, diarrhea, abdominal pain, dehydration, and lethargy on the fifth day of illness. Pleuritic chest pain, a dry hacking cough, and pharyngitis have also been noted. A maculopapular rash develops between days 5 and 7 of the illness.

Esophageal cancer.Melena is a late sign of esophageal cancer. Increasing obstruction first produces painless dysphagia, then rapid weight loss. The patient may experience steady chest pain with substernal fullness, nausea, vomiting, and hematemesis. Other findings include hoarseness, a persistent cough (possibly hemoptysis), hiccups, a sore throat, and halitosis. In the later stages, signs and symptoms include painful dysphagia, anorexia, and regurgitation.

Esophageal varices (ruptured).Ruptured esophageal varices is a life-threatening disorder that can produce melena, hematochezia, and hematemesis. Melena is preceded by signs of shock, such as tachycardia, tachypnea, hypotension, and cool, clammy skin. Agitation or confusion signals developing hepatic encephalopathy.

Gastritis.Melena and hematemesis are common with gastritis. The patient may also experience mild epigastric or abdominal discomfort that's exacerbated by eating, belching, nausea, vomiting, and malaise.

Mallory-Weiss syndrome.

Mallory-Weiss syndrome is characterized by massive bleeding from the upper GI tract due to a tear in the mucous membrane of the esophagus or the junction of the esophagus and the stomach. Melena and hematemesis follow vomiting. Severe upper abdominal bleeding leads to signs and symptoms of shock, such as tachycardia, tachypnea, hypotension, and cool, clammy skin. The patient may also report epigastric or back pain.

Mesenteric vascular occlusion.Mesenteric vascular occlusion is a life-threatening disorder that produces slight melena with 2 or 3 days of persistent, mild abdominal pain. Later, abdominal pain becomes severe and may be accompanied by tenderness, distention, guarding, and rigidity. The patient may also experience anorexia, vomiting, fever, and profound shock.

Peptic ulcer.With a peptic ulcer, melena may signal life-threatening hemorrhage from vascular penetration. The patient may also develop decreased appetite, nausea, vomiting, hematemesis, hematochezia, and left epigastric pain that's gnawing, burning, or sharp and may be described as heartburn or indigestion. With hypovolemic shock come tachycardia, tachypnea, hypotension, dizziness, syncope, and cool, clammy skin.

Small-bowel tumors.Small-bowel tumors may bleed and produce melena. Other signs and symptoms include abdominal pain, distention, and an increasing frequency and pitch of bowel sounds.

Thrombocytopenia.Melena or hematochezia may accompany other manifestations of bleeding tendency that occurs with thrombocytoenia: hematemesis, epistaxis, petechiae, ecchymoses, hematuria, vaginal bleeding, and characteristic blood-filled oral bullae. Typically, the patient displays malaise, fatigue, weakness, and lethargy.

Typhoid fever.Melena or hematochezia occurs late in typhoid fever and may occur with hypotension and hypothermia. Other late findings include mental dullness or delirium, marked abdominal distention and diarrhea, marked weight loss, and profound fatigue.

Yellow fever.Melena, hematochezia, and hematemesis are ominous signs of hemorrhage, a classic feature of yellow fever, which occurs along with jaundice. Other findings include fever, headache, nausea, vomiting, epistaxis, albuminuria, petechiae and mucosal hemorrhage, and dizziness.

Other causes

Drugs and alcohol.Aspirin, other nonsteroidal anti-inflammatory drugs, or alcohol can cause melena as a result of gastric irritation.

Nursing considerations

▪ Monitor the patient's vital signs, and look closely for signs of hypovolemic shock.

▪ Encourage bed rest, if the patient is unstable.

▪ Provide good skin care and monitor skin integrity.

▪ Insert a nasogastric tube, if indicated, to assist with drainage of gastric contents and decompression.

▪ Prepare the patient for diagnostic tests, including blood studies, gastroscopy or other endoscopic studies, barium swallow, and upper GI series, and for blood transfusions as indicated by his hematocrit.

Patient teaching

▪ Explain the underlying cause of melena and its treatment.

▪ Explain bowel elimination changes that the patient needs to report.

▪ Stress the importance of colorectal cancer screening.

▪ Reinforce the need to avoid aspirin, other nonsteroidal anti-inflammatory drugs, and alcohol.

Pictures

Book Source Details

• Book Title: Nursing: Interpreting Signs and Symptoms
• Author(s): Springhouse
• Year of Publication: 2007
• Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.

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Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: Nursing: Interpreting Signs and Symptoms Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-58255-668-7

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