Best invesigation in hirschsprung disease:
Correct Answer: Rectal biopsy
Description: Ans: A (Rectal biopsy) Ref: Sabislon Textbook of Surgery. 19th edition. Page 1849Explanation:Hirschsprung disease (HD)Absence of ganglion cells in the myenteric (Auerbach) and submucosal (Meissner) plexus1 in 5000 live births. M:F 4:1Neurogenic parasympathetic abnormalityMuscular spasm of distal colon and internal anal sphincter - functional obstruction - abnormal bowel is contracted distal segment and the normal bowel is the proximal dilated portionAganglionosis begins at anorectal lineRectosigmoid - 80%; splenic or transverse colon 17%; entire colon 8%Transition zone: Area between dilated and contracted segments - ganglion cells begin to appear, in reduced numbers3-5%' have Down syndromeRisk for HD is greater with family historyAbnormal locus on the chromosome 10 identified; associated w ith the RET oncogene>90% present with progressive abdominal distention, bilious vomiting and failure to pass meconium w ithin first 24 hours of lifeDiarrhea may develop due toenterocolitisEnterocolitis i.s the most common cause of death in patients with uncorrected HD - Diarrhea alternating with obstipation, abdominal distention, fever, hematochezia. and peritonitis.Diagnosis:Initial diagnostic step in a newborn: distal bowel obstruction is a barium enema.Normal barium enema: Rectum is wider than sigmoid colonHD; spasm of distal rectum - smaller caliber compared to proximal sigmoidIdentification of transition zone may be helpful in diagnosis of HDFailure to evacuate instilled contrast completely after 24 hoursExclude other causes of constipation in the newborn - meconium plug and small left colon syndrome, atresiaManometry: Failure of the internal sphincter to relax when the rectum is distended with a balloonRectal biopsy: gold standard- Newborn period - Bedside with special suction rectal biopsy instrument- Obtain biopsy specimen from at least 2 cm above the dentate line to avoid sampling the normal transition from ganglionated bowel to paucity or absence of ganglia in the region of the internal sphincter- Older children: full-thickness biopsy under general anesthesia (thicker rectal mucosa is not amenable to suction biopsy)- Features:deg Absent gangliadeg Hypertrophied nerve trunksdeg Robust immunostaining for acetylcholinesterase (AChE)deg Loss of calretininimmunostaining- superiorto AChEin evaluation of suction rectal biopsiesSurgical ManagementTraditionally: Leveling colostomy, confirmation of transition zone by frozen section evaluation of multiple seromuscular biopsiesDiverting colostomy (end or loop) in the region of normal ganglionated bowelDefinitive surgical options:Swenson procedure; Aganglionic bowel removed down to the level of the internal sphincters:coloanal anastomosisDuhamel procedure: Aganglionic rectal stump left in place and ganglionated normal colon is pulled behind the stumpSoave technique: Endorectal mucosal dissection within aganglionic distal rectum; Normally ganglionated colon then pulled through the remnant muscular cuff;coloanal anastomosisNowadays* performed in newborn period as a primary procedure without an initial colostomyConstipation is the most frequent postoperative problem: others - soiling, incontinence, and entprocolitis
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