II. Exam: Normal Stool

  1. First few newborn stools are normally black and tarry (meconium)
  2. Subsequent stools become yellow-brown with a seedy consistency
  3. Normal stools may also vary from green to a darker brown
  4. Stool frequency varies between several times daily to every few days

III. Causes: Dark or black stool or bloody Emesis (upper gastrointestinal source)

  1. Upper Gastrointestinal Bleeding (uncommon in newborns)
  2. Ingested blood from cracked maternal nipples during Lactation
  3. Swallowed maternal blood from delivery
    1. Distinguish newborn blood from maternal blood with the Modified Apt Test
    2. Fetal Hemoglobin contains 2 alpha subunits and 2 gamma subunits (contrast with beta subunits in adults)
      1. Fetal blood is resistant to denaturation when alkali is applied (fetal blood remains pink)
      2. Adult blood denatures in contact with alkali and turns brown

IV. Causes: Bright red stool (lower gastrointestinal source)

  1. Precautions
    1. Exclude serious causes before assuming a benign cause of neonatal Lower GI Bleeding
    2. Ill appearing infants should undergo extensive work-up
    3. Larger volume bleeding (even in well appearing infant) may warrant observation in hospital
  2. Serious Causes (typically with an ill appearing infant or complicated history)
    1. Necrotizing Enterocolitis
      1. Intestinal mucosa ischemic necrosis complicated by gut Bacteria translocation across the intestinal wall
      2. Consider especially in Premature Infants, or those with complicated birth history
      3. Among the first diagnoses to evaluate in an Ill appearing newborn
      4. Obtain Abdominal XRay
    2. Malrotation with Midgut Volvulus
      1. Intestinal Obstruction with progressive Vomiting
      2. Evaluate with upper GI study
    3. Intussusception
      1. May present even in newborns with intermittent inconsolability
    4. Hirschprung-Related Enterocolitis
      1. History of Hirschprung's Disease is often already diagnosed or history of not passing meconium on day 1
      2. High risk of perforation (avoid Rectal Exam, rectal medication, enemas)
      3. Consult pediatric surgery emergently
    5. Vitamin K Deficiency
      1. Consider in infants that did not receive Vitamin K at birth (e.g. out of hospital delivery)
    6. Coagulopathy (e.g. Sepsis, liver failure, Coagulation Factor deficiency)
      1. Rarely presents as Gastrointestinal Bleeding (other bleeding sites are more common)
      2. Obtain Complete Blood Count
  3. Benign Causes (well appearing infant)
    1. See Swallowed Maternal Blood (Breast fed infant) as above
    2. Milk Protein Allergy
      1. Distal colon, non-IgE mediated inflammation due to cow milk Protein reaction
      2. Responds to maternal diet change in Lactation, or formula change in infants
    3. Anal Fissures
      1. Uncommon; consider Constipation Causes including Cystic Fibrosis
      2. Avoid diagnosing an Anal Fissure without actually seeing the fissure
    4. Food or medication ingestion
      1. Red Gatorade
      2. Baby Percy (Pepto-Bismol like product containing Salicylates, which infants should NOT be given)

V. Causes: White Stool (acholic stool)

  1. Biliary Atresia
    1. Requires emergent evaluation and Consultation (best outcomes are with early management)
  2. Other biliary tract lesions
    1. Biliary tract cyst, bile plugs or stones
    2. Biliary tract tumors
    3. Neonatal sclerosing Cholangitis

VI. References

  1. Mason and Woods in Herbert (2019) EM:Rap 19(2): 7-8

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