Chapter 54: Bloody Stool

I. PROBLEM

A newborn infant has passed a bloody stool. A bloody stool in a neonate can represent a spectrum of conditions from benign (eg, anal fissure, swallowed maternal blood, cows’ milk protein sensitivity) to life threatening (eg, necrotizing enterocolitis [NEC], malrotation with volvulus). It is critical to detect the cases that have significant underlying pathology, especially those that require emergent operative care.

II. IMMEDIATE QUESTIONS

1. Is the stool grossly bloody? Hematochezia is passage of fresh blood through the anus. It can be pure blood, bright red or maroon colored, or blood mixed with stool. A grossly bloody stool usually signifies lower gastrointestinal (GI) bleeding (typically below the ligament of Treitz, the anatomic landmark of the duodenojejunal junction), which includes the jejunum, ileum, cecum, colon, rectum, and anus. Hematochezia can occur rarely with massive upper GI tract bleeding with a rapid transit time. Necrotizing enterocolitis (NEC) is the most common cause of bloody stool in premature infants and is critical to identify.

2. Is the stool otherwise normal in color but with streaks of blood? This is more characteristic of a lesion in the anal canal, such as an anal fissure. Anal fissure is the most common cause of rectal bleeding in the first 2 years of life and is the most common cause in well-appearing infants.

3. What is the consistency of the stool? A hard stool usually signifies constipation, which can cause a fissure, whereas a loose or diarrheal stool usually signifies colitis.

4. Is the stool black and tarry looking? Melena is the passage of black or tarry stools through the anus. Melena usually suggests the blood is from the upper GI tract (proximal to the ligament of Treitz which includes the esophagus, stomach, or duodenum). Melena can also be from bleeding from the small bowel or proximal ascending colon if transit time is slow enough to allow bacteria to denature the hemoglobin. Nasogastric trauma and swallowed maternal blood are common causes.

5. Is the stool occult blood (fecal occult blood testing) positive only? Microscopic blood as an isolated finding is usually not significant in the neonate. Tests for occult blood are very sensitive and can be positive with conditions such as repeated rectal temperature measurements or perianal dermatitis.

6. How old is the infant? The age of the infant is important as it can give clues to the diagnosis. For the first week of life consider: swallowed maternal blood syndrome, vitamin K deficiency bleeding (early or classic onset), Hirshsprung disease, malrotation with midgut volvulus, term infant with NEC. For infants less than 1 month of age, consider: anal fissure, malrotation with midgut volvulus, NEC, colitis, and milk allergy. For infants usually 1 month or older consider: lymphonodular/nodular lymphoid hyperplasia, milk protein allergy, late onset VKDB, intussusception.

7. Was the infant given vitamin K at birth? What were the maternal medications during her pregnancy? This should be asked of all parents especially if the infant is ...