Motility disorders of the GI tract - Paul MK

Question 1

Gastroparesis

Answer 1

“Stomach paralysis” –> impairment of food transit W/O obstruction. Syndrome with many causes.

Question 2

Functional dyspepsia

Answer 2

A syndrome term for discomfort/pain in the upper abdomen related to eating.

Can have organic causes (eg dyspepsia is secondary to something else). Functional dyspepsia is essentially idiopathic.

Prevalence 20-25% lifetime

Question 3

Esophageal Manometry. What is it.

Answer 3

Measures the pressure in the esophagus using a tube run through the nose and down through the nasopharynx.

Question 4

What is the criteria for a positive gastric emptying study? How is it performed?

Answer 4

Eat radioactive eggs.

Abnormal: retention >60% at 2 hr or >10% at 4 hr

Question 5

What defines a neuropathic cause of decreased gastric motility?

Answer 5

Damage to the enteric nervous system. (any cause)

Myenteric plexus or submucosal plexus.

Question 6

What defines a myopathic cause of decreased gastric motility?

What might be some examples?

Answer 6

Diseased gastric muscles. Can be due to a genetic defect (dystrophy), or acquired (scleroderma)

Question 7

What is achalasia? What are the hallmarks?

Answer 7

Patient may have dysphagia and heartburn.

Hallmarks: Absence of peristalsis and no lower esophageal sphincter (LES) relaxation

Question 8

What is the principal pathological abnormality of scleroderma?

high yield.

Answer 8

Smooth muscle atrophy and gut wall fibrosis

Motility issues everywhere in the GI tract.

[Scleroderma is a small vessel vasculitis]

Question 9

What type of process is scleroderma?

Answer 9

Myopathic

Question 10

What are some symptoms of scleroderma?

Answer 10

Dysphagia due to absence of peristalsis.

GERD due to lack of contraction of the esophageal sphincter.

Question 11

IN the esophagus, there are a gradient of excitatory neurons. More excitatory neurons near the top, more inhibitory neurons near the bottom. This is important for movement (timing) of the food bolus. Which neurons are inhibitory, cholinergic or noncholinergic?

Answer 11

Noncholinergic. There are more of these near the LES.

Question 12

What is receptive relaxation? What mediates it?

Answer 12

The vagus nerve mediates relaxation of the smooth muscle as soon as you swallow, to allow distension. The food is subsequently moved and churned down through the duodenal sphincter.

Question 13

Liquid emptying of the stomach occurs by:

Answer 13

tonic pressure gradient

Question 14

Solid emptying of the stomach occurs by:

Answer 14

vagally mediated contractions.

Question 15

What symptom might a lung transplant lead to, and why?

Answer 15

Severing of part of the vagus leads to gastroparesis. This would be an example of a neuropathic cause of gastric immotility.

Question 16

Imaging shows dilation of the small bowel without occlusion. What is the likely condition?

What is a complication?

Answer 16

Chronic Intestinal Psuedo-Obstruction (CIPO)

Stasis–> bacterial overgrowth –> fermentation and malabsorption–> bloating

NOTE: this is a syndrome, so it can have many causes.

Question 17

An infant born with CIPO will not survive past one year of age, generally. True or false.

Answer 17

False. 1/3 of infants die before the age of 1

Question 18

What are the two types of peristalsis in the colon?

Answer 18

Haustra–> low amplitude and rhythmic–> mixing

High Amplitute Propagated Contractions (HAPCs) for expulsion.

Question 19

Name three things that increase colonic motility.

Answer 19

Coffee
Waking up
Eating

Question 20

Diabetes. Constipation or diarrhea?

Answer 20

Constipation

Question 21

Scleroderma. Constipation of diarrhea

Answer 21

Constipation

Question 22

Hirschprungs. Constipation or diarrhea/

Answer 22

Constipation.

Question 23

How is the Sitz test performed? What defines normal/abnormal.

Answer 23

Eat radioopaque mini-doughnut looking-things.

Xray at 5 DAYS.

Less than 5 = normal
Greater than 5 in rectum–> defecatory disorder
Greater than 5 in colon–> motility disorder

Question 24

What is the fundamental defect in Hirschprungs disease?

Answer 24

Internal sphincter does not relax appropriately. Cannot void.

Hirschsprung’s is a congenital absence of myenteric neurons of the distal colon. As a result, there is no reflex inhibition of the IAS following rectal distention.
It is more common in Males compared with female and occurs in 1 in 5000 births

Question 25

What is the name of the muscle that loops around the colon which has to relax a bit before you can poop?

Answer 25

Puborectalis.

Question 26

What is dyssynergic defecation?

Answer 26

Paradoxical contraction of the pelvic floor and external anal sphincters –> straining to poop while clenching the external sphincter.

Question 27

A 2 year-old presents for an outpatient gastroenterology consultation for inadequate weight gain.
He was born in his parent’s home in rural South Dakota.
His parents note that in addition to not gaining much weight, he has been constipated his entire life. He has one bowel movement every 4-5 days. Diagnosis?

Answer 27

Hirschprungs.