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CM 23- Encopresis, Constipation, Hirschprungs, Megacolon Objectives • Know the classic presentation and physical exam findings consistent with Hirschsprung’s disease. • Describe the histologic findings consistent with a diagnosis of hirschsprung’s disease. • Name the gold standard diagnostic test for hirschsprung’s • Define toxic megacolon, know the most commonly associated disease, symptoms, treatment for and contraindicated diagnostic studies. • Define constipation and encopresis • List functional constipation/encopresis treatment options for both disimpaction and maintenance Hirschprung Disease • Congenital aganglionic megacolon- neurocristopathy • Absence of ganglion cells in the submucosal and myenteric plexus • Incidence of 1 in 5,000 live births • Most common cause of lower intestinal obstruction in neonates • Male:female ratio is 4 : 1 and 1:1 (short vs long segment) • Associated with other congenital defects- Down Syndrome • Microcephaly, mental retardation, abnormal facies, autism, cleft palate, hydrocephalus, and micrognathia. Pathology • Consequence of an arrest of neuroblast migration from the proximal to distal bowel • Inadequate relaxation of the bowel wall and bowel wall hypertonicity, lead to intestinal obstruction • Limited to the rectosigmoid in 80% of patients, 10% -5% of patients have long-segment disease • Total bowel aganglionosis- 5%- rare • Histologically is an absence of Meissner and Auerbach plexus and hypertrophied nerve bundles • High concentrations of acetylcholinesterase between the muscular layers and in the submucosa • Inheritance- sporadic, dominant and recessive patterns Clinical manifestations • Distended abdomen • failure to pass meconium • and/or bilious emesis (neonatal period) • Failure to thrive with hypoproteinemia • Stool dilatation increase intraluminal pressure, decrease blood flow • Proliferation of bacteria enterocolitis (Clostridium difficile, Staphylococcus aureus, anaerobes, coliforms) diarrhea, abdominal tenderness • Sepsis and signs of bowel obstruction • Tympanitic and distended- with a large fecal mass • Ultrashort-segment • Ganglionic segment is limited to the internal sphincter • Ganglion cells are present, anorectal manometry is abnormal • Long-segment (5%) • Involving the entire colon • The extent determined accurately by biopsy at the time of laparotomy Rectal Examination • Normally placed anus- snug • The rectum empty of feces • Explosive discharge of foul-smelling feces and gas • The stools can consist of small pellets, be ribbon-like, or have a fluid consistency • Retained feces may be associated with pain and fever • Urinary retention with enlarged balder or hydronephrosis CM 23- Encopresis, Constipation, Hirschprungs, Megacolon Diagnosis • Gold standard- rectal suction biopsy • The biopsy specimen should be stained for acetylcholinesterase to facilitate interpretation • hypertrophied nerve bundles that stain positively for acetylcholinesterase with an absence of ganglion cells • Unprepared contrast enema –looking for an abrupt narrow transition zone- proximal and distal colon • Compare rectum to that of the sigmoid colon • 10% of newborns have a normal contrast study • Anorectal manometry (helpful for dx) • measures the pressure of the internal anal sphincter while a balloon is distended in the rectum • the internal anal sphincter fails to relax in response to rectal distention • Equivocal or paradoxical response- rectal biopsy Treatment • Definitive treatment is operative intervention • Primary pull-through procedure • 3 basic surgical options – Swenson- excise the aganglionic segment and anastomoses – Duhamel- create a neorectum – Soave- the endorectal pull-through procedure • Treatment of choice laparoscopic single-stage endorectal pull-through procedures Lateral view of a barium enema in a 3 yr old girl with Hirschsprung disease. The aganglionic distal segment is narrow, with distended normal ganglionic bowel above it. CM 23- Encopresis, Constipation, Hirschprungs, Megacolon Constipation Constipation: Two or fewer stools per week OR passage of hard, pellet-like stools for at least 2 weeks. Functional Constipation: Two or fewer stools per week, voluntary withholding of stool, and infrequent passage of large diameter, often painful, stools. • Encopresis: Fecal Incontinence caused by leakage of retained stool • Caused by either a defect in filling or emptying the rectum. • It is self-perpetuating: • Causes: Nonorganic (Functional) Organic • One of the most common causes for generalized abdominal pain in children. • PE - LLQ mass of impacted stool may be felt. Causes of Organic Constipation Anatomic - Anal Stenosis - Imperforate Anus - Anteriorly Displaced Anus - Intestinal Stricture Abnormal Musculature - Prune Belly Syndrome - Gastroschisis - Down Syndrome Intestinal Nerve or Muscle abnormalities • Hirschprung • Visceral Myopathy or Neuropathy • Intestinal Neuronal Dysplasia Spinal Cord Defects • Tethered Cord • Spinal Cord Trauma • Spina Bifida • Drugs (Narcotics, Anticholinergics, Lead) • Metabolic Disorders • Hypokalemia • Hypercalcemia • Hypothyroid • Diabetes • Intestinal Disorders • Celiac Disease • Cow’s Milk Protein Intolerance • Cystic Fibrosis (Meconium Illeus) • IBD (stricture) • Tumor • Connective Tissue Disorders • SLE • Scleroderma • Psychiatric • Anorexia • • CM 23- Encopresis, Constipation, Hirschprungs, Megacolon Long term effects: - Patient anxiety and family stress. - Enuresis - Accompanying Urinary tract stasis – UTIs - Encopresis – watery stool from the proximal colon leaks around hard retained stool and may pass unnoticed by the child. 5-10 year olds typically effected. Often mistaken for diarrhea. Children typically present with soiling • Recurrent Urinary Tract Infections – detrusor instability, which can lead to – urinary incontinence, – large bladder capacity, and – dyscoordinated voiding • 30% of chronically constipated- urinary incontinence, 11% urinary tract infection • 13% of urinary retention had functional constipation Functional Constipation/Encopresis Treatment • Disimpaction – Enemas, Glycerin suppositories or oral laxatives. - Polyethylene glycol (PEG) 1.5g/kg/day • Maintenance - Diet modification – water, fiber, fruit juices - Behavioral Therapy – scheduled toilet times - Laxatives - Polyethylene glycol 1g/kg/day, Lactulose 1-3 ml/kg/day, Glycerin suppositories • Long treatment course with frequent relapses Oral Medications • Osmotic agents- lactulose (a synthetic disaccharide), sorbitol, and polyethylene glycol (PEG 3350) • Lubricants- mineral oil • Stimulants- promote enhanced colonic transit (eg, senna, bisacodyl) avoided as long-term therapy CM 23- Encopresis, Constipation, Hirschprungs, Megacolon • • • • Megacolon Toxic Megacolon- complication of inflammatory bowel disease – total or segmental nonobstructive colonic dilatation plus systemic toxicity congenital megacolon (Hirschsprung's disease) idiopathic or acquired megacolon – chronic constipation of any etiology – intestinal pseudoobstruction lack of systemic toxicity distinguishes these presentations from true toxic megacolon Case 1- Constipation • 11 yo male admitted to PICU with Severe Dehydration, abdominal distension, and Altered Mental Status • Last bowel movement > 1 month ago • Born premature at 35 weeks to a drug-addict mother, adopted at birth • VSD closed spontaneously, ADHD, severe developmental delay; he functions at level 4-5 years old • Chronic constipation (functional), rectal biopsy at age 8 yrs ruled out Hirshsprung disease • Rx with laxatives and purgatives all his life (frequent “Fleet Phoshpo-Soda” Enema) Labs: • Na+ 144 (133-143) • K+ 5.7 (3.4-4.7) • Ca++ 6 (8.9-10.3) • Mg++ 4.1 (1.7-2.4) • PO4- 26 (3.3-6.2) • PH+ 7.16 (7.34-7.44) • HCO3- 15 (22-26) Abd X-ray: • Fecal Impaction • Distended loops of colon ECHO: • LVSF 6% (NR >30%) • [It was 38% at age 8] What happened • 10pm >> ER • 2am >> PICU • 12:30pm >> Cardiac Arrest and Asystole > Vtach>Sinus Rhythm • 7pm >> C. Arrest and Asystole> VTach> PEA (Echo poor contractility) • 7:49pm >> Resuscitation Stopped & Pronounced Death Dx: Chronic Constipation >>> Toxic Megacolon Severe Electrolyte Imbalance >>> Severe Myocardial Depression and Cardiac Arrhythmias Key points (Board Exam Favorites) • Hirschprung: The rectum empty of feces and Explosive discharge of foul-smelling feces and gas • Gold standard for Hirschsprung disease- rectal biopsy • Down Syndrome- Hirschprung disaease- association • Definition of constipation: 2 or fewer stools/wk OR passage of hard, pellet-like stool for at least 2 wks • First line of therapy of constipation-beside diet modificatiob- osmotic agents-polyethylene glycol • Encopresis could be mistaken for diarrhea (encopresis is constipation that finally expels as water when disimpacted, uncontrollable)