Colorectal Quiz: Episode 46 - Hirschsprung's Disease

Trisomy 21 is associated with approximately 50 times higher incidence of Hirschsprung disease compared to non-trisomy 21 patients, with about 5-10% of trisomy 21 patients having Hirschsprung disease.

Rectal irrigations for Hirschsprung enterocolitis should use 20 mL per kg, 3 times a day, with warm saline to avoid hypothermia in small children.

In Hirschsprung disease with free air, perforation typically occurs in the cecum when the transition zone is around the hepatic flexure, due to Laplace's law causing the cecum to perforate as the most dilated segment.

In anorectal malformation patients with delayed diagnosis, perforation typically occurs in the sigmoid colon as a linear longitudinal tear along the taenia.

Irrigation technique requires instilling small aliquots of saline (20-40 mL at a time) and then evacuating it rather than just infusing into the colon lumen.

Hirschsprung disease is almost never an emergency operation; irrigation usually wins the day.

Contrast enema findings of rectosigmoid ratio less than 1, saw-toothing pattern in the rectum, and hyperperistalsis are indicative of Hirschsprung disease with associated enterocolitis.

Definitive pathologic diagnosis of Hirschsprung disease requires absence of ganglion cells on 100 levels and presence of hypertrophic nerves greater than 40 microns.

Frozen section can only definitively tell you it is NOT Hirschsprung disease by showing ganglion cells, but cannot confirm it IS Hirschsprung disease because that requires 100 levels showing no ganglion cells anywhere.

Calretinin staining is used as an adjunct diagnostic tool; if calretinin is present it indicates ganglion cells are nearby, while absent calretinin further confirms Hirschsprung disease.

Experts recommend waiting minimum 4 weeks after treating enterocolitis before performing definitive pull-through surgery, as long as the patient is receiving good irrigations and growing and healthy otherwise.

Literature from the PCPLC and Michael Rawlins shows that delayed definitive surgery for Hirschsprung disease (around 3 months out) has similar outcomes to earlier surgery.

If a Hirschsprung patient is not being fed due to ongoing issues, diversion is a reasonable next step rather than continuing irrigations at home.

For leveling biopsies, the recommended strategy is to start with sigmoid biopsy; if frozen section shows ganglion cells, no other biopsies are necessary.

When mapping the colon without frozen section available, biopsies should be taken from left colon, transverse colon, and hepatic flexure/distal ascending colon, as cecal pull-throughs do not succeed very well.

The appendix should not be biopsied for Hirschsprung mapping because many patients' appendixes are aganglionic and it should be saved for possible future use.

When going to OR electively for pull-through and finding no ganglion cells in sigmoid/left colon, the surgeon should not proceed with pull-through that day but should biopsy transverse colon and hepatic flexure, do an ileostomy, and wait for permanent section before discarding any colon.

Frozen section interpretation can be unreliable in the setting of active enterocolitis due to inflammation obscuring ganglion cells.

In resource-limited settings without frozen section capability, the strategy is to bring up the dilated portion of colon which is more likely to be functional, and ileostomy is not an option due to inability to manage dehydration with quick medical access.

Modern telemedicine technology allows pathologists to evaluate H&E stained slides for ganglion cells via Zoom using a camera and microscope, enabling better surgical planning in resource-limited settings and potentially saving 80% of colons in rectosigmoid Hirschsprung disease.

Approximately 80% of Hirschsprung disease cases are rectosigmoid in extent.

Ileostomy is preferred over colostomy for diversion in Hirschsprung disease because colonic diversion can shorten the mesentery through division and inflammation, making subsequent pull-through technically more difficult with inadequate reach.

Frozen section should be performed on the ileostomy site to ensure it will function properly.

Patients who had Hirschsprung surgery with overstretched sphincters developed fecal incontinence but never got enterocolitis, demonstrating that sphincter preservation paradoxically maintains susceptibility to enterocolitis.

Hirschsprung patients cannot relax their internal sphincter even after pull-through, which is why they remain susceptible to enterocolitis despite technically successful surgery.

A published study of Botox injection at one month post-operatively for Hirschsprung disease showed no benefit in preventing enterocolitis.

Botox injection at the anal sphincter at time of ileostomy closure is being studied prospectively but is not 100% effective, as some patients in the protocol still developed enterocolitis.

Families should be sent home with irrigation equipment and taught irrigation technique before pull-through surgery, with parents practicing the technique, to avoid having catheters go through the anastomosis post-operatively when issues arise.