Hirschsprung's disease

Question 1

Definition

Answer 1

Aganglionosis->partial or complete obstruction due to tonically contracted lumen

Question 2

When does it present

Answer 2

Usually within first year of life.

Question 3

Cingenital associations

Answer 3

Down syndrome

Anorectal rarely

Question 4

Why misdiagnosis of Hirschsprungs and anorectal

Answer 4

Most patients born with anorectal malformations with present with a degree of constipation

Question 5

Chromosomal abnormality

Answer 5

Associated with deletion in long arm xsome 10

Question 6

Key features in pathological diagnosis

Answer 6

Absence of ganglion cells
Hypertrophic nerve
Increased acetylcholinesterase

Question 7

Pathohysiology

Answer 7

arrest in the craniocaudal migration of the neuroenteric ganglion cells from the neural crest into the upper gastrointestinal tract, down through the vagal fibres, and along the distal intestine-> ganglion cells are missing from the Auerbach myenteric plexus, the Henle plexus, and at the Meissner plexus->para/sympathetic affected, uncoordinated contraction.

Question 8

Response of muscle

Answer 8

Spasm, lack of propulsive peristalsis and mass contraction->lack relaxation of bowel/internal sphincter
Develops megacolon

Question 9

Presentation in neonate

Answer 9

Failure to pass meconium in first 48 hours
Billous vomiting
Enterocolitis
Explosive passage of liquid and foul stools
Abdominal distension
Fever
Failure to thrive

Question 10

Presentation in older children

Answer 10

Chronic constipation

Question 11

Strong risk factor

Answer 11

Downs syndrome

Question 12

Investigations

Answer 12

Plain abdominal xray
Contrast enema
?rectal biopsy

Question 13

Findings on abdominal xray

Answer 13

Air fluid level

Distended bowel loops

Question 14

Findings in enema

Answer 14

Narrowed distal colon with dilation of proximal

Question 15

Findings on biopsy

Answer 15

Absence of ganglion cells
Thickened non-myelinated nerves
\+Acetycholinesterase
-ve NADP neurons
\+ACh nerve bundles

Question 16

Differentials

Answer 16

Meconium plug
CF with meconium ileus
Hypothyroidism
Chronic constipation
Cerebral injury

Question 17

Management of typical without enterocolitis

Answer 17

Bowel irrigation

Definitive surgery

Question 18

Management of typical with enterocolitis

Answer 18

Bowel irrigation
IV antibiotics
Decompression by colostomy
Definitive surgery

Question 19

Management of total colonic aganglionosis

Answer 19

Ileostomy

Definitive surgery

Question 20

Short segment disease

Answer 20

Resection
Bowel irrigation
IV antibiotics

Question 21

When may there be occassional passage of stool w/ diarrhea

Answer 21

When only a few centremetres of the rectum are affected

Question 22

What are the three surgical procedures for repair

Answer 22

Swenson rectosigmoidectomy
Duhamel retrorectal transanal pullthrough
Soave endorectal pullthrough

Question 23

Describe the surgery for repair

Answer 23

Remove the denervated segment and bring to the unaffected anus

Question 24

Short term risks of operation

Answer 24

Normal operative and anaesthetic risks

Anastomosis leak/breakdown

Question 25

Complications (6)

Answer 25

Recurrent enterocolitis
Constipation
Stricture
Prolapse
Epianal abscess
Fecal soiling

Question 26

What is the most important complication and why

Answer 26

Enterocolitis, major cause of mortality

Question 27

Outline the post-operative monitoring (3)

Answer 27

Observe for enterocolitis (diarrhea and fever)
Receive follow up until toilet trained
Soiling after toilet training needs medical treatment

Question 28

What is an important cause and management if enterocolitis persists beyond 1 year

Answer 28

Anatomical cause

May need to redo the pull through procedure

Question 29

Prognosis

Answer 29

Excellent

Question 30

Percentage and type of defractory problems following surgical treatment

Answer 30

10-20%
Enterocolitis
Incontinence
Persistent constipation