Name
CONGENITAL MEGACOLON
DESCRIPTION
DETAIL
CAUSES : Congenital absence of Auerbach’s and Meissner’s autonomic plexuses in bowel wall - usually limited to the colon -------------------------------------------------------------------------- DIFFERENTIAL DIAGNOSIS • Megacolon, secondary (to Chagas disease) • Megacolon, acquired, functional • Functional constipation • Hypoganglionosis • Meconium plug syndrome • Small left colon syndrome • Meconium ileus* Electrolytes, albumin, CBC, urinalysis, thyroid function SPECIAL TESTS . Proctoscopy: Ampulla empty of feces . Biopsy: Absence of ganglia in wall of narrowed rectum . Anorectal manometry IMAGING * X-ray - barium enema shows: . Large ovoid mass mottled by small, irregular gas shadows . Dilatation of sigmoid colon above narrowed distal sigmoid or rectum . Narrowed portion rippled or segmented . Fluid levels within bowel . Diaphragm elevated DIAGNOSTIC PROCEDURES : . Suction aspiration biopsy of bowel wall . Barium enema . Proctosigmoidoscopy . Large bowel wall biopsy . Laparoscopy: Normal proximal colon dilatation . Anorectal manometry: Internal sphincter relaxation failure
TYPENOTES
RISK FACTORS: F. H/O Hirschsprung disease, Offspring risk if parent has short segment-2%; if parent has long segment-up to 50%, Sibling risk if male affected-female has 0.6% risk(short seg.), Sibling risk if female aff.- male has 18% risk (long seg.)GENERAL MEASURES: . Treatment may be symptomatic or definitive . May need emergency correction of fl uid and electrolyte imbalance . Removal of fecal accumulation - retention enemas of 3-4 ounces (90-120 mL) of mineral oil followed by repeated colonic irrigations with isotonic saline solution. Avoid use of other solutions, e.g., water, soapsuds enemas. SURGICAL MEASURES: . Inpatient surgery . Proximal colostomy and resection of agangliononic bowel is gold standard (and necessary when there is significant proximal dilation) . Definitive pull-through procedure (Duhamel, Soave, or Swenson) when dilation has resolved (usually 2-4 months) . Single stage procedure may be possible in infants . Transanal pull-through in infants . Laparoscopic technique may be used . Confirmation of normal ganglion cells mandatory at colostomy site and proximal resection site prior to anastomosis DRUG(S) OF CHOICE: • None recommended for treatment • Preliminary to surgery: Bowel prep with neomycin or nystatin ALTERNATIVE DRUGS: • Metronidazole (Flagyl) for bowel preparation PATIENT MONITORING : Closely until recuperated fully from surgical intervention POSSIBLE COMPLICATIONS: . Toxic enterocolitis, possibly fatal . Bleeding and/or perforation EXPECTED COURSE/PROGNOSIS: . Favorable . Requires long-term followup * Requires aggressive management of any suspected Hirschsprung enterocolitis with: . Rectal irrigation . IV antibiotics . Nasogastric decompression PATIENT EDUCATION : • After surgery instruct parents to detect and report dehydration, decreased urinary output, sunken eyes, poor skin turgor, vomiting, fever • Encourage bonding with parents by having parents participate in child’s care as much as possible • Request enterotomy therapist to teach family
RELATED DISEASE
Not Available Disease
DISEASE
INVESTIGATION
SERUM PROTEIN TOTAL, SERUM SODIUM, SERUM POTASSIUM, SERUM CHLORIDE, URINE ROUTINE, X-RAY BARIUM ENEMA, COMPLETE BLOOD COUNT, SIGMOIDOSCOPY, BIOPSY, THYROID PROFILE