49: Bloody Stool

A newborn infant has passed a bloody stool. This is generally a benign and self-limiting disorder. In a large majority of patients, the cause is unknown, but it is important to detect the cases that have significant underlying pathology.

1. Is the stool grossly bloody? Hematochezia (bright red or maroon colored stool) is usually an ominous sign; an exception is a bloody stool as a result of swallowed maternal blood, which is a benign condition. A grossly bloody stool usually signifies lower gastrointestinal (GI) bleeding (typically below the ligament of Treitz, which is the anatomic landmark of the duodenojejunal junction): it includes the jejunum, ileum, cecum, colon, rectum, and anus. Hematochezia can occur rarely with massive upper gastrointestinal tract bleeding. Necrotizing enterocolitis (NEC) is the most common cause of bloody stool in premature infants and should be strongly suspected.

2. Is the stool otherwise normal in color but with streaks of blood? What is the consistency of the stool? This is more characteristic of a lesion in the anal canal, such as anal fissure. Anal fissure is the most common cause of bleeding in well infants. A hard stool usually signifies a fissure; a loose or diarrheal stool signifies colitis.

3. Is the stool black and tarry looking? Melena (black or tarry stools) suggests blood in the stool from the upper gastrointestinal tract (proximal to the ligament of Treitz: esophagus, stomach, or duodenum). It can also be from bleeding from the small bowel or proximal ascending colon if transit is slow enough to allow bacteria to denature the hemoglobin. Nasogastric trauma and swallowed maternal blood are common causes.

4. Is it occult blood (fecal occult blood testing/hemoccult) positive only? Microscopic blood as an isolated finding is usually not significant. Tests for occult blood are very sensitive and can be positive with repeated rectal temperatures or any perianal dermatitis.

5. Was the infant given vitamin K at birth? Hemorrhagic disease of the newborn or any coagulopathy may present with bloody stools.

6. What medications are the mother and infant on? Certain medications can cause bleeding. If the mother was on thiazides, phenobarbital, oral anticoagulants, or anticonvulsants, these can cross the placenta and cause coagulation abnormalities in the infant. If the infant has been given nonsteroidal anti-inflammatory drugs, heparin, tolazoline, indomethacin, or dexamethasone, these are all associated with bleeding.

7. Is the infant well or is the infant ill? Infants with NEC, Hirschsprung enterocolitis, or volvulus are ill; infants with an anal fissure, a milk protein allergy, or nodular lymphoid hyperplasia can appear well.

The most common routine reasons are swallowed maternal blood and fissures. Significant hemorrhages are usually caused by a duodenal or gastric ulcer.

1. Melena (black tarry stools). Usually from the upper GI tract but can be from the small bowel or proximal colon, as noted previously.

   1. Maternal blood. Swallowing of maternal blood during delivery (melena neonatorum) accounts for 30% of infant “GI bleeding.” Infant has normal meconium, then swallowed blood usually appears in the stool on the second or third day of life (second or third stool has blood). Swallowing of blood during breast-feeding (secondary to cracked and bleeding nipples) can also cause this. Swallowing of bloody amniotic fluid from antepartum hemorrhage associated with bleeding into the amniotic fluid for several hours before birth is rare. This usually presents in the first stool.

   2. Nasogastric tube trauma.

   3. Coagulopathies. Hemorrhagic disease of the newborn occurs from a deficiency in vitamin K–dependent coagulation factors and can be prevented if vitamin K is administered at birth. Melena typically appears on the second or third day of life. Severe hemorrhage can occur in about 0.25–0.50% of neonates. Other coagulopathies: liver failure found in some metabolic disorders (iron storage disorder) or ischemic injuries, infections (sepsis).

   4. Formula intolerance/dietary protein intolerance. Milk protein sensitivity is secondary to cow's milk or soybean formula, and symptoms of blood in the stool usually occur in the second or third week of life. Infants usually have a mucoid bloody diarrhea.

   5. Other GI causes

      1. NEC. Usually presents with bloody stool but can also have melena.

      2. Gastritis/stress ulcer/esophagitis/erosions/gastritis. Occurs in up to 20% of infants in the neonatal intensive care unit (NICU). Prematurity, stress, and mechanical ventilation are associated with stress gastritis. Hemorrhagic gastritis can occur from tolazoline and theophylline therapy. Indomethacin is associated with gastric mucosal injury. Stress ulcer is a common cause and can occur in the stomach or duodenum and is associated with prolonged severe illness or steroid therapy. Maternal stress in the third trimester may increase maternal gastrin secretion and contribute to a peptic ulcer in the newborn. Esophagitis can occur from trauma from pharyngeal, esophageal, or gastric suction at birth. A gastric and esophageal lesion together is unique to neonates. Erosions of the esophageal, duodenal, and gastric mucosa are a common cause of bloody stool. Mallory-Weiss or iatrogenic tear is a tear in the esophagus that is an unusual cause of upper gastrointestinal bleeding in an infant.

      3. Congenital GI tract malformations

         1. Anatomic. Intestinal malrotation, duplication cysts, anatomic duplications, Meckel diverticulum, Hirschsprung disease.

         2. Vascular. Gastrointestinal hemangiomas can present with GI bleeding. Associated syndromes with vascular malformations of the GI tract are Down syndrome, Klippel-Trenaunay syndrome, Osler Weber Rendu disease, and blue rubber bleb nevus syndrome.

   6. Unknown cause. Many cases of bloody stool in an infant have no identifiable cause.

   7. Rare causes. Gastric teratoma, gastric Dieulafoy lesion, GI tract telangiectasia, heterotopic pancreatic tissue in the stomach, pyloroduodenal intestinal duplication, and dengue shock syndrome.

2. Grossly bloody stool (hematochezia). Usually from lower GI tract (jejunum, ileum, colon) but can be from the upper GI tract with rapid transit time (rare).

   1. Swallowing of maternal blood with rapid transit time.

   2. Necrotizing enterocolitis. Rare in the first couple of days of life. Emergency room (ER) presentation at 16 days of age with bloody stool in a term neonate.

   3. Coagulopathies. Disseminated intravascular coagulation (DIC)—there is usually bleeding from other sites and it may be secondary to an infection. Hemorrhagic disease of the newborn occurs from a deficiency in vitamin K–dependent coagulation factors and can be prevented if vitamin K is administered at birth. Bloody stools typically appear on the second or third day of life. Severe hemorrhage can occur in 0.25–0.50% of neonates. Bleeding diathesis—platelet abnormalities and clotting factor deficiencies can cause bloody stools. Hemophilia can present as GI hemorrhage. Severe liver disease can cause a coagulopathy.

   4. Surgical diseases

      1. Malrotation with midgut volvulus. Obstruction after birth and possible bleeding with ischemic damage or other causes of volvulus.

      2. Meckel diverticulum. Painless rectal bleeding (rule of 2's: 2% of population, length 2 inches, within 2 ft of ileocecal valve, 2 times as common in males, diagnosed in the first 2 years of life, 2 types of tissue present).

      3. Hirschsprung enterocolitis. Ten to thirty percent present with GI bleeding and abdominal distension; failure to pass meconium and feeding intolerance.

      4. Intussusception. Rare in the neonatal period; incidence is greatest in infants 3 months to 1 year of age. Most present with typical symptoms: bloody stool (“currant jelly” stool), abdominal mass, vomiting, and intermittent screaming. Intrauterine intussusception presents with a complete ileus.

      5. Gastrointestinal duplications. Colonic and tubular are least uncommon but do occur; presents with obstruction or abdominal mass and bleeding can occur due to presence of ectopic gastric mucosa or stasis.

      6. Incarcerated inguinal hernia. Infants are typically very irritable, refuse to eat, and on physical examination have a tender firm mass in the inguinal canal.

      7. Rare causes. Rectal polyp (more common in toddlers but can occur in newborns); acute appendicitis; duplication cyst induced by a congenital ileal polyp.

   5. Colitis can be secondary to the following:

      1. Intestinal infections (bacterial enteritis). Rare in neonatal period and more common in older children and adults.

      2. Food allergy (common cause in newborns). Dietary/formula intolerance factors, including allergy and dietary protein-induced colitis. The top allergens are cow's milk products and soy. There are multiple disorders: Allergic enterocolitis can present with massive bloody stool, and lab data show no eosinophilia. Rectal mucosal biopsy shows eosinophilic infiltration. Neonatal transient eosinophilic colitis—there are cases of infants with this with no known allergic component involved (no prior feeding had occurred). Eosinophilic gastrointestinal disorders (EGIDs) are disorders where there is primary eosinophil inflammation in the gastrointestinal tract. Food protein–induced proctocolitis (FPIPC)—presents with bright red rectal bleeding with mucus in healthy neonate. Infant can occasionally have mild peripheral eosinophilia. Mainly in breast-fed infants but can be found in infants receiving cow's milk or soy. Nodular hyperplasia is found on endoscopy. Food protein–induced enterocolitis syndrome (FPIES)/dietary protein–induced enterocolitis syndrome (DPIES): non–IgE-mediated immune reaction in GI tract portions or entire GI tract involvement. Rare in breast-fed infants. Hematochezia in exclusively breast-fed infants presents at an average age of 7.4 weeks. Diarrhea is the most common symptom (also mild anemia, red and white cells in stool, negative culture, colitis on colonoscopy) and may represent sensitivity to protein eaten by the mother. The hematochezia disappears after the mother is on a protein-free diet.

3. Streaks of bright red blood coating a normal or hard stool. Most commonly associated with a perianal disorder.

   1. Anal fissure can be secondary to constipation and straining. This is the most common cause of bleeding in infants: spots of blood in the diaper or a strip of blood on the outside of one side of the stool. Etiology is a tear of the anal canal at the mucocutaneous line from a hard stool. Deeper rectal fissures can also occur.

   2. Rectal trauma may be secondary to temperature probes.

   3. Perianal irritation and excoriations can cause small amounts of blood. This can be from a diaper rash.

   4. Rare causes. Rectal prolapse is reported with chronic constipation, cow's milk allergy, Shigella diarrhea, rectal parasite infections, Hirschsprung disease, high anorectal malformations, and cystic fibrosis. Perianal abscess/fistula in ano is common in infants <1 year of age. It can originate from anal cryptitis, which then forms a perianal abscess. Proctitis—eosinophilic proctitis from cow's milk protein intolerance can present with rectal bleeding and proctitis.

4. Bright red blood mixed in with a normal /loose stool. This suggests bleeding from the lower GI tract. May occur from a proximal source with some degree of digestion of blood.

   1. Eosinophilic proctocolitis. This is also called protein-induced proctitis or milk-induced enterocolitis. Blood mixed with normal stools (sometimes with mucus) in a healthy infant that occurs most commonly in breast-fed infants, but can occur with cow's milk, soy protein–based, or hydrolysate formula.

   2. Lymphonodular/nodular lymphoid hyperplasia (of the rectosigmoid area). Characterized by multiple masses of lymphoid nodules that are usually present in the terminal ileum or colon. It disrupts the normal mucosa and leads to thinning of the mucosa and bleeding. Etiology is unknown. It can occur from cow's milk allergy or an immunologic response.

5. Occult GI blood by fecal occult blood testing/hemoccult

   1. Positive fecal occult blood test/hemoccult test/stool guaiac. As an isolated finding, is usually not significant. Tests for occult blood are very sensitive and can be positive with repeated rectal temperatures or any perianal dermatitis.

   2. Can be positive earlier in breast/cow's milk–fed infants and in more significant diseases such as esophagitis, gastritis, Meckel diverticulum, vascular malformations, eosinophilic gastroenteritis, polyps, colitis and others.

   3. NEC. Presence of occult blood does not correlate with the development of NEC.

6. Blood spots in a diaper (non-GI causes). This can be from other etiologies beside the gastrointestinal tract: hematuria, severe diaper rash with excoriation, blood from a circumcision, vaginal bleeding in a female infant (pseudomenses—withdrawal of maternal hormones). Reddish-orange spots (“brick stain”) in the diaper are from uric acid crystals in the urine and are usually benign but may indicate concentrated urine. A red stained diaper can also be from bile pigments or porphyrins.

The age of the infant is important. If the infant is <7 days old, swallowed maternal blood is a likely cause; in older infants, this is unlikely. Ask the mother about medications taken during pregnancy. Is the infant breast-feeding? Get a detailed description of the stool since type of stool and color of blood can all help to differentiate the bleeding source (see Section III above).

1. Physical examination

   1. Evaluate the infant's peripheral perfusion. An infant with NEC can be poorly perfused and may appear to be in early or impending shock. Bruising may suggest a coagulopathy.

   2. Examine naso-/oropharyngeal area for a source of bleeding.

   3. Abdominal examination. Check for bowel sounds and tenderness. Hyperactive bowel sounds are more common in upper gastrointestinal bleeding. If the abdomen is soft and nontender and there is no erythema, a major intra-abdominal process is unlikely. If the abdomen is distended, rigid, or tender, an intra-abdominal pathologic process is likely. Abdominal distention is the most common sign of NEC. Abdominal distention may also suggest intussusception or midgut volvulus. If there are red streaks and erythema on the abdominal wall, suspect NEC with peritonitis. Malrotation with ischemic bowel can also present with peritonitis. If there is an abdominal mass, consider duplication. Consider Hirschsprung disease or malrotation if there is obstruction. Hepatomegaly, splenomegaly, or jaundice may indicate liver disease.

   4. GU/anal examination. Does the infant have a rash? If the infant's condition is stable, perform a visual examination of the anus to check for anal fissure or tear. Look for polyps, masses, or fistulas. Gentle digital rectal examination with a lubricated pinky finger may reveal fissures or polyps. Bedside “anoscopy” can be done by placing a lubricated blood collection tube into the anus.

2. Laboratory studies

   1. Initial studies

      1. Fecal occult blood testing (FOBT). Hemoccult or other test for the presence of blood. This is not useful for screening for NEC. It is positive in more cow's milk–fed infants than formula-fed infants.

      2. Apt test. To differentiate maternal from fetal blood if swallowed maternal blood is suspected. A positive test indicates that the blood is due to either gastrointestinal or pulmonary bleeding from the neonate. A negative test would indicate that the blood is of maternal origin.

      3. CBC with differential. If a large amount of blood is lost acutely, it takes time for it to be evident on hemoglobin results; therefore, initial hemoglobin values may be unreliable. An increased white blood count suggests infection or thrombocytopenia (can be associated with NEC, sepsis).

      4. Chemistry panel. High BUN can be seen in upper GI bleeding (resorption of blood in GI tract).

      5. Coagulation studies. To rule out DIC or a bleeding disorder. The usual studies are partial thromboplastin time (PTT), prothrombin time (PT), fibrinogen level, and platelet count. Thrombocytopenia can also be seen with cow's milk–protein allergy. An elevated PT can indicate a coagulopathy. A prolonged PTT may indicate hemophilia.

      6. Suspected NEC. If NEC is suspected, the following studies should be performed:

         1. CBC with differential. To establish an inflammatory response and to check for thrombocytopenia and anemia.

         2. Serum potassium levels. Hyperkalemia secondary to hemolysis may occur.

         3. Serum sodium levels. Hyponatremia can be seen secondary to third spacing of fluids.

         4. Blood gas levels. To rule out metabolic acidosis, which is often associated with sepsis or NEC.

   2. Further studies

      1. Stool studies. Certain pathogens cause bloody stools, but they are rare in the neonatal nursery. Obtain stool cultures for common pathogens, ova, and parasites. Stool smear for white blood cells (WBCs; elevated with colitis) and eosinophils (suggests allergic colitis).

      2. Allergic enterocolitis diagnosis. Difficult because there is no specific laboratory test. Eosinophilia may be present in the serum and can be present in the stool. A rectal mucosal punch biopsy can show eosinophilic infiltration suggestive of an allergic origin.

3. Imaging and other studies

   1. Immediate study

      1. Abdominal radiograph. A plain radiograph of the abdomen is useful if NEC or a surgical abdomen is suspected. Look for an abnormal gas pattern, a thickened bowel wall, pneumatosis intestinalis, or perforation. Pneumatosis can appear as a “soap bubble” area (see Figure 11–23). If a suspicious area appears on the abdominal radiograph in the right upper quadrant, it is usually not stool. A left lateral decubitus view of the abdomen may show free air if perforation has occurred and it cannot be seen on a routine anteroposterior (AP) film. Surgical conditions usually show signs of intestinal obstruction. Most common sign in intussusception in premature infants is dilated bowel loops.

   2. Additional studies

      1. Abdominal ultrasound with color Doppler studies to diagnose intussusception. A pseudo kidney (longitudinal appearance of the intussuscepted segment of bowel) is seen with intussusception and Meckel diverticulum.

      2. Contrast studies can be done for diagnosis of obstruction.

      3. Endoscopy of upper gastrointestinal tract allows visualization of the esophagus, stomach, and duodenum and helps to identify the site of bleeding in the upper tract.

      4. Electronic gastroscopy can be done in infants at 0–3 months. This can be used to assess upper gastrointestinal bleeding.

      5. Meckel scan (technetium-99m pertechnetate nuclear scan) can help diagnose Meckel diverticulum.

      6. Radioactive tagged red blood cell (RBC) scan can localize the site of lower GI bleeding if the source is unknown.

      7. Colonoscopy can be done to rule out colitis, polyps, or other masses.

      8. Rectal mucosal biopsy can show eosinophilia in the lamina propria in cases of allergic enterocolitis.

      9. CT scan to evaluate for obstruction or see gastrointestinal hemangiomatosis.

Based on the clinical status of the infant: Is the infant critically ill? Is the infant in shock? Is the infant who presents with blood in the stool well?

1. Critically ill infant. Follow basic ABCs, and pass nasogastric/orogastric (NG/OG) tube. Aggressive volume replacement if hypotension/hypovolemia is present. Make NPO and consider broad-spectrum antibiotics. Correct acidosis and fluid disturbances if appropriate. Do immediate laboratory and radiograph studies. Consider surgical consultation and initiation of peripheral nutritional support.

2. Noncritically ill infant. Rule out non-GI causes of blood, especially if there was just blood on a diaper (see Section III.F). Rule out swallowed maternal blood, blood from breast-feeding, and an anal fissure. Then do the following:

   1. Place the infant NPO.

   2. Start the workup. Initial laboratory tests and abdominal radiograph.

   3. Antibiotics. Some institutions will start the infant on antibiotics while the workup is done depending on the clinical status of the infant.

   4. For isolated rectal bleeding. Placing the infant NPO for 1 day and antibiotics for 2 days was not associated with increased deterioration or recurrent episodes of isolated rectal bleeding.

3. Individual plans as follows:

   1. Swallowed maternal blood. Observation only.

   2. Anal fissure and rectal trauma. Observation is indicated. Petroleum jelly applied to the anus may promote healing.

   3. Necrotizing enterocolitis. See Chapter 113.

   4. Nasogastric trauma. In most cases of bloody stool involving nasogastric tubes, trauma is mild and requires only observation. If the tube is too large, replacing it with a smaller one may resolve the problem. If there has been significant bleeding, gastric lavages are helpful; it is controversial whether tepid water or normal saline is best. Then, if possible, removal of the nasogastric tube is recommended.

   5. Formula intolerance. Difficult to document acutely, and is usually diagnosed if the patient has remission of symptoms when the formula is eliminated. In breast-fed infants with rectal bleeding, the use of lactobacillus was not supported by the literature. Cow's milk allergy should be treated with a cow's milk–free diet and then those who become symptom-free should be rechallenged to reduce the number of false-positive diagnoses.

   6. Gastritis or ulcers. Treatment usually consists of ranitidine (preferred because of fewer side effects) or famotidine. Use of antacids in neonates is controversial; some clinicians believe that concretions may result from the use of antacids. Use of antacids increases the risk of infection and feeding intolerance in infants receiving gavage feedings. (See Chapter 55.)

   7. Unknown cause. If no cause is found, the infant is usually closely monitored. In the majority of the cases, the bleeding subsides.

   8. Nodular lymphoid hyperplasia. Change the infant's formula to a hypoallergenic type.

   9. Intestinal infections. Antibiotic treatment and isolation are standard treatment.

   10. Hemorrhagic disease of the newborn. Intravenous vitamin K is usually adequate therapy (see Chapter 87). Fresh frozen plasma (FFP) and red cell transfusions are sometimes needed.

   11. Surgical conditions (eg, NEC, perforation, volvulus). All require immediate surgical evaluation. Intussusception can be reduced with an enema in most cases.