Constipation and Megacolon

Question 1

Definition of constipation

Answer 1

Less than 2 BM/week for 12 months
or
less than 3 per week for 12 mths with straining/hard stool over 25% of the time

Question 2

Normal motility in the colon depends on what

Answer 2

Smooth muscle contraction (circular layers)

Less longitudinal contraction in the colon

Question 3

Short duration colonic contractions cause

Answer 3

mixing

less than 15 seconds

Question 4

Long duration

Answer 4

mixing and local propulsion

Question 5

What type of colonic movement causes mass movement of feces?

Answer 5

Giant migrating complex

Question 6

Food instigates a gastrocolic reflex to make room for more food. This is mediated by

Answer 6

CCK

Question 7

Gastrocolic reflex is proportional to qhat?

Answer 7

Caloric content of meal

Question 8

CCK and colonic contractions

Answer 8

CCK stimulates frequency and amplitude of contractions

Question 9

Pg F stimulates

Answer 9

Longitudinal muscle contraction

Question 10

PgE does what

Answer 10

inhibits circular muscle contraction

Question 11

Serotonin does what?

Answer 11

mediates intestinal peristalsis

Question 12

What is the most important neurotransmitter in the brain gut interaction>

Answer 12

Serotonin

Question 13

Serotonin released by what types of cells

Answer 13

Enterochromaffin cells

Question 14

80% of total body serotonin is present where?

Answer 14

GI tract

Question 15

Constipation more common in pts that are 65 or older and esp in women

Answer 15

ok

Question 16

When investigating the causes of Constipation realize that primary causes are generally rare (except IBS). Secondary causes shuld usually be investigated first…

Answer 16

Think about:
- Drugs
Think about neurogenic vs. non-neurogenic causes

Question 17

KNOW Etiology stuff

Answer 17

ok

Question 18

95% of pediatric c0onstipation is

Answer 18

functional…they don’t want to use the bathroom at school or something

Question 19

Complains of constipation but transit study is normal. This IBS

Answer 19

ok

Question 20

Severe idiopathic chronic constipation is most common in who?

Answer 20

Women

Question 21

Sitz marker study investigates

Answer 21

normal colonic transit

Question 22

Puborectalis muscle does what during defecation

Answer 22

relaxes

Question 23

Normal defecation is associated with relaxation of teh puborectalis and external anal sphincter muscles, together with increased abdominal pressure and inhibition of colonic segmenting activity

Answer 23

ok

Question 24

Dyssynergic defecation

Answer 24

Ineffective defecation is associated with a failure to relax, or inappropriate contraction of, the puborectalis and external anal sphincter muscles

Question 25

Hirchsprung Disease

Answer 25

Congenital disorder characterized by constipation from birth and colonic dilatation proximal to a spastic, non-relaxing and non-propulsive segment of distal bowel.

Question 26

Epidemiology of Hirchsprung

Answer 26

More common in males (4:1)

10% of cases in Down Syndrome

Question 27

Pathogenesis of Hirchsprung

Answer 27

Absence of ganglion cells in large bowel, functinal obstruction and proximal dilatation

Rectum is always involved, rectum and sigmoid in most cases, very rare for the entire colon to be involved

Question 28

Clinical presentation of Hirchsprung disease

Answer 28

• failure to pass meconium
• obstructive constipation, occasional passage of stool
• bouts of diarrhea, abdominal distension

Question 29

Gold standard for diagnosis of Hirchsprung

Answer 29

Rectal biopsy

May also do abdominal radiographs, contrast enema,anorectal manometry, etc

Question 30

Differential for megacolon

Answer 30

• Rule out obstruction
• C. Dif Colitis
• IBD due to ulcerative colitis or Crohn’s disease
• Adynamic colon….very common, must rule out the others first though