What’s the diagnosis? 4 things to think of when the newborn hasn’t pooped
December 24, 2024
Merry Christmas/Happy Holidays to all. My gift to everyone is a repost on the free side of a favorite topic: 4 things to think of when the newborn hasn’t pooped.
For breastfeeding, it takes a village – thank you for all YOU do. And thank you for being here.
The Case
This is a 40-hour-old male infant who was born at 39 weeks by a vaginal birth to a 28-year-old G1P0-1 woman with an unremarkable pregnancy. The infant has been breastfeeding well with a good latch and the mother is able to express quite a few drops of colostrum after each feed which she is giving to the baby. The resident calls to share that the nurses notified her that the baby has not passed any stool since birth (40 hours). The resident examined the infant and reports that the infant appears well, has a soft abdomen and what appears to be an opening at the anus. Bowel sounds are present. The infant has had no spitting or vomiting. On her review of the chart and speaking with the parents, no meconium was noted to date, including after birth.
So, what do you think?
The Basics
First, know the basics - When is a newborn expected to poop after birth?
From an older study, 99% of healthy, full-term infants pass the first stool within 24 hours of birth. By 48 hours, all healthy, full-term infants in this study had passed a stool. (1)
The stool should go from meconium to a transitional stool to a breastmilk stool which looks like French’s mustard with cottage cheese in it.
My resident did an excellent job in reviewing the history (including no meconium noted at birth) and presenting the physical exam (including counting the holes). Sometimes the charting can be off, so I asked her to go ask the parents if they had noted any stools that perhaps the nurse was not aware of. She did and the parents have not seen any poop since birth.
Let’s review what should be in the top four conditions on your differential diagnosis.
#1. Meconium plug syndrome
This is the mildest, most common form of distal obstruction in infants. It is transient - once the plug is passed the infant stools normally. This occurs in 1/500-1/1,000 infants and is due to inspissated (thickened) immobile meconium. Rectal stimulation with a rectal thermometer can help with this. (2,3)
#2. Meconium ileus (seen with conditions like cystic fibrosis)
I get this one confused with meconium plug syndrome. So instead of meconium ileus I think of cystic fibrosis because cystic fibrosis is the underlying disorder in most meconium ileus diagnoses. Cystic fibrosis is one of the most common genetic disorders in white people in the United States, occurring in one of every 3,200 live births. It is less common in African Americans (1 in 17,000), Asian Americans (1 in 31,000) and Native Americans. While still unusual in Hispanics, it is increasing in prominence over time (1 in 4,000 to 10,000). It certainly should be on the differential list of all infants who have delayed pooping. (4)
When asked, the parents do not know of any family members with cystic fibrosis. Cystic fibrosis is included on the newborn metabolic screen in our state (Massachusetts, USA) – check to see if it is included where you live.
#3. Hirschsprung Disease
Hirschsprung Disease is a congenital disorder (a disorder present at birth) in which the infant is missing nerve cells in the large intestine, usually in the distal part of the colon. “Without these nerve cells, the muscles can’t move food and waste through that part of the large intestine. Stool can’t move forward. It stays in the large intestine.” (5) It occurs in 1/5000 live births and is 4 times more common in males. 8% of patients with Hirschsprung Disease also have Down Syndrome.
The resident and I went to exam the infant and we checked for an anal wink. To check for this, we stroked the anus with a soft cotton tip and saw the anal sphincter muscles wink or contract. A patient with Hirschsprung Disease will not exhibit that wink.
#4. Anorectal malformations
An imperforate anus is a congenital defect in which a normal anal opening is absent at birth. This condition occurs in 1 out of 5,000 infants.
Regarding the anatomy, several things can be going on:
The rectum may end in a blind pouch that does not connect with the colon
The rectum may have openings to the urethra, bladder, the base of penis or scrotum in boys or the vagina in girls
There may also be stenosis (narrowing) or a complete absence of the anus.
VACTERL Syndrome
An imperforate anus can be associated with other defects that can be remembered by using the mnemonic: VACTERL.
Vertebral defects – for example, small hypoplastic vertebrae or hemivertebra
Anal defects – anal atresia/imperforate anus
Cardiac defects – most commonly ventricular septal defect (VSD), atrial septal defect (ASD), or Tetralogy of Fallot
Tracheoesophageal fistula
Renal defects – Complete or partial renal genesis or other genitourinary system anomalies
Limb defects – including missing or displaced digits, polydactyly (extra digits), or syndactyly (webbed or fused fingers or toes)
To make the diagnosis of VACTERL Syndrome, at least 3 of defects must be present.
Imperforate anus can be hard to pick up on the physical exam. It can present as delayed stooling, a distended abdomen, or stool exiting the body from an abnormal spot like the vagina. This case is a good reminder to count the holes on the newborn physical exam.
The diagnosis
Our baby passed a meconium plug after a rectal temperature was taken and then passed a lot of meconium. Had the newborn not stooled with the rectal temp, the next thing we would have done was obtain an abdominal plain film. We would have been looking for signs of intestinal obstruction on the film.
A baby has to poop at least once to get out of Dodge. (A baby has to pass stool before it is safe to be discharged from the Post-Partum unit.)
References
Clark DA. Times of first void and first stool in 500 newborns. Pediatrics. 1977 Oct;60(4):457-459. https://pubmed.ncbi.nlm.nih.gov/905009/
https://www.ncbi.nlm.nih.gov/books/NBK562320/
Loening-Baucke V, Kimura K. Am Fam Physician. 1999;60(7):2043-2050.
https://cystic-fibrosis.com/statistics