GOOD MORNING!Monday, August 6th, 2012

NEONATES: FIRST STOOL Healthy full term neonates:

60% stool in first 8 hours 91% by 16 hours 98.5% by 24 hours >99% by 48 hours

Premature neonates: 95% stool by 48 hours

ILLNESS SCRIPT Predisposing Conditions

Age, gender, preceding events (trauma, viral illness, etc), medication use, past medical history (diagnoses, surgeries, etc)

Pathophysiological Insult What is physically happening in the body, organisms

involved, etc.

Clinical Manifestations Signs and symptoms Labs and imaging

BARIUM ENEMA

BARIUM ENEMA

HIRSCHSPRUNG: PREDISPOSING CONDITIONS Sporadic or familial (4 gene mutations

identified) Male predominance (3.8:1) Slightly more common in African-American

and Asian ethnicities 70% are isolated birth defect 30% associated with other disorders

Trisomy 21 Waardenburg, Laurence-Moon-Biedl, Smith-Lemli-

Opitz, MEN type IIa, congenital central hypoventilation syndrome (Haddad syndrome)

HIRSCHSPRUNG: PATHOPHYSIOLOGY Congenital absence of ganglion cells in the

myenteric and submucousal colonic plexuses Failure of migration of ganglion cell precursors to migrate

from the neural crest to GI tract (5-12 WGA) Begins at the internal anal sphincter and extends

proximally to a variable distance The earlier the arrest in migration occurs, the longer the

segment involved Abnormal innervation disrupts the inhibitory

paraympathetic nerves results in sustained contraction of the aganglionic segment Leads to colonic obstruction

80% are short segment (S-HSD) Distal to splenic flexure; often limited to rectosigmoid

20% are long segment (L-HSD) Rarely can affect entire colon and small intestine

HIRSCHSPRUNG: CLINICAL MANIFESTATIONS** Failure to pass meconium in first 24hrs of life** Abdominal distension Bilious emesis Diarrhea Feeding intolerance Short-segment HD: Presents later in childhood

Intractable constipation Ribbon-like stools Abdominal distension FTT

Rectal exam: increased tone, empty rectal vault, explosive release of stool

BARIUM ENEMA Transition zone

Narrow-diameter rectosigmoid colonic segment

Dilated/hypertrophied proximal colon

HIRSCHSPRUNG: DIAGNOSIS Barium enema: suggestive; but absence of

transition zone does not rule out HD Anorectal manometry

Tests response to balloon inflation in the region of the internal and external sphincters Normally, balloon inflation/dilation of rectum induces

relaxation of internal sphincter Absence of this relaxation indicates HD

Rectal biopsy (Gold standard)** Suction rectal biopsy at 2 and 5cm from anal verge Looking for absence of ganglion cells Acetylcholinesterase staining shows hyperplastic

axons due to absence of ganglion cells If inconclusive, may need full thickness biopsy

HIRSCHSPRUNG: COMPLICATIONS**

Enterocolitis** Bacterial infection secondary to stasis/dilated colon Watery, explosive foul-smelling stools, +/- bleeding Abdominal distension Fever Hemodynamic instability 20% mortality

Sepsis Bowel Perforation

Stricture formation after surgery

TREATMENT Surgery

Remove all or most of the aganglionic segment Reanastomose normal proximal bowel to the

distal rectum or anal canal Goal: to establish regular defecation and

maintain continence Most have a good outcome, however 30%

remain constipated or never develop fecal continence

THANK YOU!! Noon conference: NICU Radiology (Dr.

Congeni)