Daniel Hirsch, MD Director of Neonatology Somerset Medical Center Assistant Professor of Pediatrics UMDNJ RWJMS
Daniel Hirsch, MD Director of Neonatology Somerset Medical Center Assistant Professor of Pediatrics UMDNJ RWJMS
Today s s Talk Case: Term newborn with vomiting & abdominal distension Normal stooling patterns Pathophysiology of Hirschsprung s Disease Signs of Hirschsprung s Differential diagnosis Diagnosis & management of Hirschsprung s Treatment of Hirschsprung s
Neonate with vomiting & abdominal distension Mom 25 y.o., primigravid Good prenatal care Normal level II US GBS positive ROM 6 hrs (clear fluid) No fever No meds given NSVD Apgar scores 8@1, 9@5
Neonate with vomiting & abdominal distension Normal phys exam @ 1 hr Exclusively nursing Passed meconium @ 20 hrs Abd distension @ 30 hrs Vomiting x 1, non bilious Lethargic Temp 98.8 F Resp rate 76 Room air sat.s 98%
Neonate with vomiting & abdominal distension Initial management?
Initial Management CR monitor & pulse oximetry Complete physical exam BP Bedside glucose Place naso or oro gastric tube CBC w differential, lytes, ABG, blood culture Flat plate of abdomen, consider additional view for intraperitoneal air Immediate consultation with Pediatric surgeon Ampicillin & gentamicin and IV fluids
Normal Stooling Patterns 95 99% healthy term newborns pass meconium by 24 hrs 100% pass meconium by 48 hrs Hirschsprung s Disease: 5% pass meconium by 24 hrs 40 50% pass meconium by 48 hrs
Stooling Patent GI tract GI smooth muscle Peptide Hormones GI hormones Enteric nervous system Nerve fibers Neurotransmitters & receptors Anal sphincters (internal & external)
Enteric Nervous System Most complex part of peripheral nervous system Derived from neural crest cells
Enteric Nervous System Innervation of GI tract normally complete by 7 8 weeks gestation Neural crest cells must then proliferate, differentiate & migrate enteric nervous system Mature innervated GI tract by 14 weeks gestation
Hirschsprung s s Disease Dr. Harald Hirschsprung Two children with megacolon, 1887 Dr. Tittel noted absence of ganglion cells in distal colon 1901
Pathophysiology of Hirschsprung s Congenital absence of enteric ganglia (myenteric & submucosal plexuses), aganglionosis in variable segment of distal bowel Abnormal peristalsis & motility in aganglionic segment
Pathophysiology of Hirschsprung s Intrinsic malfunction of intestinal tract ** Intestinal obstruction **
Histopathology
Hirschsprung s s Disease 80% of cases aganglionosis of rectosigmoid region short segment 20% of cases also involves colon and even small intestine Rare aganglionosis may be near total
Epidemiology of Hirschsprung s Incidence: 1 in 5000 Males > Females Long segment: 2 : 1, autosomal dominant Short segment: 4 : 1, autosomal recessive Genetically determined? Risk of recurrence in siblings 3 4% ( 200 times) Other anomalies in 5 35% of cases Sporadic cases: 80%
Why does Hirschsprung s s occur? Two theories 1. Neural crest cells differentiate prematurely 2. Neural crest cells reach their destination but fail to survive
Signs of Hirschsprung s s Dz In FT newborn: Failure to pass meconium in first 24hrs Abdominal distension Vomiting (+/ bilious) Poor feeding Lethargy Irritability Diarrhea Fever
Differential Diagnosis Functional obstruction vs. Mechanical obstruction
Differential Diagnosis Intestinal malrotation ** Necrotizing enterocolitis ** Sepsis (non GI etiology)
Differential Diagnosis Left microcolon Meconium plug syndrome Meconium ileus +/ cystic fibrosis Intestinal atresia Enterocolitis Anal atresia Abdominal mass Hypokalemia Hypermagnesemia Hypothyroidism Maternal opiates
Meconium Plug Syndrome
Diagnosis & Management ** Timely & expeditious ** Serial & thorough assessments ** Vitals Accurate I & O s NPO & IV fluids (** may need extra fluids **) Gavage tube +/ decompression Plain film of abdomen Consider additional view(s) intraperitoneal air
Diagnosis & Management Pediatric surgical consultation ** CBC with manual diff, blood culture, electrolyte panel, LFTs Urine culture? CSF evaluation & culture? Contrast enema Rectal (suction) biopsy definitive Genetic consultation if other anomalies present
*Rectal Biopsy * Size of specimen: diameter= 2 3 mm Depth= 1 mm Absence of ganglion cells (myenteric & submucosal plexuses) ** Ideal specimen not always obtained Ancillary criteria may be used: Large submucosal fibers Acetycholinesterase staining
Histopathology
Treatment Resection of aganglionic segment Specific procedure dependent upon length of aganglionic segment Short segment (rectosigmoid): Soave endorectal pull through Longer segment (proximal to rectosigmoid) Transabdominal & perineal procedure +/ colostomy above aganglionic segment
Treatment Intestinal transplantation? Enteric nervous system (ENS) stem cell transplantation?
Wrap Up Differential diagnosis *Consider potential life threatening diagnoses* Serial & thorough assessments Prompt pediatric surgical consultation Diagnosis depends on biopsy: no ganglia in myenteric & submucosal plexuses risk in subsequent children (genetic?)