Clinical Presentation

Clinical presentation depends almost exclusively upon the underlying etiology. The history and examination are important to narrow the field of possible etiologies. The presence or absence of related symptoms and/or signs is often helpful to establish the cause. Rectal bleeding may be in the form of hematochezia, melena, or occult blood. Hematochezia, although usually from a distal gastrointestinal lesion, can occur from either upper or lower gastrointestinal sources. Melena or tarry stools only occur when the bleeding is from a lesion proximal to the ligament of Treitz.

Perhaps the most common presentation of rectal bleeding in infancy is an otherwise healthy-appearing infant noted by the parents to have a small amount of bright red blood on the diaper or on the outside of stool. An anal fissure is the most likely etiology in this scenario and is often identifiable as a small tear or ulceration at the anal verge usually located posteriorly. Anal fissures are very unusual in breast-fed infants. However, in children going from formula to cow's milk, allergic colitis is not unusual due to the cow's milk protein allergy. These children also have spotty bleeding on stool, mixed with stools, or present on toilet paper as their complaint.

Necrotizing enterocolitis (NEC) may also produce rectal bleeding in infancy (usually in premature infants), although rectal bleeding is seldom the primary symptom. The diagnosis is suggested by history which may include prolonged gastric emptying, feeding intolerance, apnea, jaundice, abdominal distension, vomiting, thrombocytopenia, leukocytosis, or other signs ofsepsis. Recurrent rectal bleeding after recovery from NEC suggests recurrent NEC or a postNEC gastrointestinal stricture.

Intussusception occurs most commonly in infants between 6 and 18 months of age. Rectal bleeding associated with intussusception is classically described as having a "currant-jelly" appearance, which is probably only apparent in about a third of cases. Intermittent abdominal pain is the usual distinguishing symptom. A palpable sausage-shaped abdominal mass helps establish the diagnosis. A pneumatic enema is performed to both confirm and reduce the intussusception.

An acute onset of melena and bilious emesis in an otherwise healthy baby suggests malrotation with midgut volvulus. At onset, the physical examination may be unremarkable. With time, the abdomen will become progressively distended and tender to palpation. An upper gastrointestinal contrast study should be obtained immediately to confirm the diagnosis. Emergent laparotomy is indicated. Gangrenous bowel from midgut volvulus or other causes (segmental small bowel volvulus, internal hernia, sigmoid volvulus, etc.) is the second most common source of rectal bleeding in infants between one and 12 months of age.

Rectal bleeding may also be a presenting sign of intestinal duplication or Meckel's diverticulum with ectopic gastric mucosa.