Delayed Stooling in Neonates

1. Delayed Stooling in Neonates Shruti Patel, MSIII UNSOM

2. Normal Passage • Healthy full term infants • 99% pass meconium within 24 hours of birth • 100% pass meconium within 48 hours of birth • Preterm infants • 37% pass within 24 hours • 99% pass within the 9th day after birth

3. Clinical Presentation • Failure to pass meconium in a timely fashion • Abdominal distention • Refusal to feed • Bilious vomitting • Palpable distended loops of bowel

4. Case • A 3,480 g (7 lb, 7 oz) male infant was born after 40 weeks' gestation to a 27 yo G2P1 mother via NSVD . There were no complications during the pregnancy and delivery. He did not pass meconium in the first 24 hours and had the onset of vomiting on the first day. His abdomen became mildly distended. The infant was not able to feed, and abdominal distention increased by day 2.

5. Case • Rectal examination revealed a tight anus. On the second day, flat and upright abdominal films demonstrated numerous loops of dilated bowel. Barium enema radiographic examination showed that most of the dilated bowel was colon.

6. Differential • Hirschsprung's disease • Meconium plug syndrome • Meconiumileus • Anorectal malformation • Small left colon syndrome • Iatrogenic • Hypoganglionosis • Neuronal intestinal dysplasia type A • Neuronal intestinal dysplasia type B • Megacystis-microcolon-intestinal hypoperistalsis syndrome

7. Hirschsprung's Disease • Congenital aganglionicmegacolon • Incidence : 1 out of 4000 live births; 20-25% cases of neonatal bowel obstruction • Males: Female = 4:1 • 8% also have Down Syndrome • Eight genetic mutations identified: most common – RET proto-oncogene • Also associated with MEN2, anomalies of kidneys and urinary tract, congenital heart disease and other genetic disorders

8. Pathophysiology • Defect in craniocaudal migration of neural crest cells to innervate the large intestine during first 12 weeks of gestation • Distal portion of the colon lacks network of nerves: Auerbach’sand Meissner’splexus • Affected segment cannot relax and pass stool through • Most often involves the rectosigmoid and internal anal sphincter

9. Clinical Presentation • Failure to pass meconium in first few days of life • Abdominal distention, refusal to feed, vomitting • Passage of meconium plug followed by sparse BM • Anus and rectum narrow and empty of stool • explosive expulsion of gas and stool after the digital rectal examination (squirt sign or blast sign)

10. Complications • Enterocolitis • Potentially life threatening • Due to proliferation of bacteria due to stasis • Sepsis like presentation • Fever, vomitting, diarrhea, GI bleeding • Can progress to toxic megacolon • fluid resuscitation, intravenous antibiotic therapy, rectal irrigations, emergency colostomy.  • Volvulus • Rare complication • Sigmoid colon ; less common involvement of transverse colon

11. Diagnosis • Rectal Biopsy • Gold standard • Diagnosis established if ganglion cells absent • Abdominal Radiographs • Distal intestinal obstruction • Dilated bowel loops proximal to aganglionic region • Contrast Enema: • Cone shaped transition zone • AnorectalManometry • Useful when segment involved is ultrashort • Relaxation of int. anal sphincter w/ distention of rectum excludes HD. - rectosphinteric reflex

12. Treatment/Outcome • Surgical resection of affected segment • Bring normal ganglionic bowel down to anus • Anal dilatations Long term Complications: • Constipation • Fecal incontinence • Enterocolitis • Occurs within 1st year post-op • Major cause of morbidity and mortality • Increased risk in long-segment disease

13. Meconium Plug Syndrome • Mild and transient functional distal obstruction • Inspissated immobile meconium • Unclear etiology • Incidence : 1/500-1000 live births • Delayed passage of meconium > 24-48 hrs • Intestinal dilation

14. Diagnosis/Treatment • Plain abd. radiograph: • Gaseous distention of intestinal loops without fluid levels • Contrast Enema: • Both diagnostic and therapeutic • Rectal Stimulation: • Thermometer or digital rectal exam Normal BM after the plug is passed. All symptoms resolve*

15. Meconium Ileus • Obstruction at the level of terminal ileum with inspissatedmeconium • 30% of intestinal obstruction cases • 50% of ML patients with undamaged gut • 50% associated with volvulus, atresia, perforation • 15% of CF present with MI • 80-90% with FT infants with MI have Cystic Fibrosis

16. Clinical Presentation • Within first three days • Failure to pass meconium • Abdominal distention present at birth • As air swallowed, within hours, increases distention  bile stained vomit • Massive distention, abdominal tenderness or abdominal erythema complications • Complex: perforation, peritonitis, atresia, volvulus; 40% of CF is complex • Simple: If no associated GI pathology

17. Diagnosis • Stabilized w/ nastograstric decompression and correction of fluid and electrolyte abnormalities • Radiography w/ contrast enema: • Diagnostic • Reveals microcolon and meconium pellets in the terminal ileum • “Ground-glass” appearance • Calcifications, large air-fluid levels indicated complications • Contraindicated if evidence of perforation

18. Treatment • Simple MeconiumIleus • Administration of diatrizoatemeglumine (Gastrografin) enema • Hyperosmolar enema breaks up meconium plug: • 16-50% success rate • Intravenous fluids • Surgical evacuation of meconium if enema unsuccessful • Complex MeconiumIleus • Perforation, peritonitis, atresia require immediate surgery • Resection, intestinal anastomosis, and ileostomy

19. Anorectal Malformations • Incidence: 1/4000-8000 • Failure of the complex embryological development involving intestinal tract and geritourinary structures

20. Anal Stenosis • 20% of anorectal malformations • Anus is very small and tight • Central black dot of meconium present • Ribbon-like stools passed after intense straining • Treatment: • Anal Dilatation • Repeated for several months

21. Anal Atresia • Imperforate or absent anus with or without fistulas • Equal incidence in males and females • High: Rectum ends above the levator muscle • Often presents with fistula ending in prostatic urethra or vagina • Low: Rectum partially descends through the levator muscle • Well formed sacrum and prominent anal dimple • Cutaneous fistula anterior to external anal sphincter near scrotum or vulva - mistaken for anus

22. Associated Anomalies • 50-70% have urologic or other anomalies present • Verterbral defects • Anal atresia • Cardiac defects • Transesophageal fistula • Esophageal atresia • Renal defects • Radial upper Limb hypoplasia

23. Diagnosis • Easy to detect on physical exam • Radiograph w/ Barium enema • X-ray: anatomical location of the malformations, also detect spine and sacrum abnormalities • Ultrasound: abnormal anchoring of spinal cord • Echocardiogram: screen for heart defects • MRI: Definite diagnosis of spinal and pelvic abnormalities

24. Treatment • Surgical correction • To preserve bowel, urinary, and sexual function • High anal atresia • Fistulas: gently dilated to allow gas and meconium to pass • Colostomy • Low anal atresia • Corrected electively when condition stable

25. Small Left Colon Syndrome • Functional distal bowel obstruction • Transient dysmotility in the descending colon • >50% - born to diabetic mothers • Resolves spontaneously • Not related to meconiuminspissation or aganglionosis • Abdominal distention, bilious vomitting, failure to pass meconium within 24 hrs

26. Diagnosis & Treatment • Abdominal radiograph: • Normal caliber rectum • Small caliber sigmoid and descending colon • Abrupt transition zone at the splenic flexure • Distended loops of bowel with air-fluid levels • Contrast Enema: • Diagnostic and therapeutic • Spontaenous passage of meconium with symptom resolution • Suction rectal biopsy and CF workup • Always done to r/o other diagnosis

27. Other Causes • Maternal medications/drugs • Illicit drugs • Magnesium sulfate • Ganglionic blocking agents • Neonatal medical conditions • Hypothyroidism • Hypercalcemia • Hypokalemia • Sepsis • CHF

28. Other Causes • Hypoganglionosis • Symptoms and radiologic findings similar to Hirschsprung’s disease – often co-exist • Reduced number of ganglion cells • Neuronal Intestinal Dysplasia • hypoplasia of the sympathetic innervationof the myenteric plexus and mucosa • mucosal inflammation. • Megacystis-microcolon-intestinal hypoperistalsis syndrome (rare) • Small bowel shortened and dilated; colon is microcolon • Megaureters and megacystis

29. Case • The surgeon performed an anal dilatation, and the infant subsequently passed gas and meconium, which was followed by resolution of all symptoms. • After discharge from the hospital, the infant's mother continued performing periodic anal dilatation because he had difficulties moving his bowel. Digital rectal examination by the physician when the infant was five weeks of age revealed a tight anus and liquid stool but no impaction. • One week later, the mother noticed a bloody ring around his bowel movements. Barium enema radiographic examination at this time showed a transition zone in the distal portion of the sigmoid colon, with marked dilatation of the descending colon and left side of the transverse colon . Anorectalmanometry showed an absent rectosphincteric reflex. No ganglion cells were seen in the rectal biopsy. These findings were consistent with Hirschsprung's disease.

30. References • Loening-Baucke V, Kimura K. Failure to Pass Meconium: Diagnosing Neonatal Intestinal Obstruction. Am Fam Physician. 1999 Nov 1;60(7):2043-2050. • Parisi MA. Hirschsprung disease overview. GeneReviews [Internet] 2002 (revised 2011). Available at: http://www.ncbi.nlm.nih.gov/books/NBK1439/ • Eggermont E, De Boeck K. Small-intestinal abnormalities in cystic fibrosis patients. Eur J Pediatr 1991; 150:824. • Yang J, Cummings EA, O'connell C, Jangaard K. Fetal and neonatal outcomes of diabetic pregnancies. ObstetGynecol 2006; 108:644. • Ellis H, Kumar R, Kostyrka B. Neonatal small left colon syndrome in the offspring of diabetic mothers-an analysis of 105 children. J Pediatr Surg. 2009;44(12):2343