Motility

Question 1

what is rectoanal inhibitory reflex (RAIR)?

Answer 1

anal sphincter relaxation with balloon distension in the rectum

relaxation of the internal anal sphincter is controlled by a reflex controlled by parasympathetic fibers. this reflex is RAIR.

Question 2

on anorectal manometry, what defines an absence rectoanal inhibitory reflex (RAIR)?

Answer 2

lack of anal sphincter relaxation with balloon distension in the rectum

Question 3

what should an absent RAIR make you concerned about?

Answer 3

an absent RAIR should raise suspicion for Hirschsprung’s disease

Question 4

what is Hirschsprung’s disease?

Answer 4

Hirshsprung disease is the agangliosis of the myenteric plexus. variable lengths of the distal colon can be affected. the ganglionic segment fails to relax and remains contracted, resulting in dilation of the more proximal colon. The failure of relaxation is attributed to the absence of inhibitory neurons containing the inhibitory neurotransmitters nitric oxide and VIP

it is synonymous with congenital megacolon.

Typical presentation: large bowel obstruction in infancy. n/v, abd distension, and constipation are common sx.

10% of pts w/ Down Syndrome have Hirschsprung.

can appear later in life w/ chronic constipation and recurrent fecal impaction

Question 5

what is the major side effect of lubiprostone? what is it used to treat?

Answer 5

nausea is the major side effect of lubiprostone (amitiza). it is used to treat IBS-C

Question 6

what is chronic intestinal pseudo-obstruction categories and how do you distinguish between them?

Answer 6

CIPO is classified as neuropathic, myopathic, or mixed.

Myopathic - on antroduodenal manometry, normal contraction frequency. Causes include systemic sclerosis (also has component of neuropathic)

Neuropathic - on antroduodenal manometry, low contraction amplitude. Causes include DM, paraneoplastic syndrome (carcinoid tumor), neurofibromatosis, multiple sclerosis.

Question 7

what do you see for distal esophageal spasm on esophageal manometry?

Answer 7

an increased proportion of swallows (>20%) w/ decreased distal latency (<4.5 sec)

Question 8

what do you see for Type II achalasia on esophageal manometry?

Answer 8

increased IRP w/ pan esophageal pressurization

also shows “bird’s beak” on esophagram

Question 9

what is the perforation risk of pneumatic dilation of the esophagus?

Answer 9

5%

Question 10

what is the first step in determining tx for achalasia?

Answer 10

determine pt’s overall health and surgical risk

pneumatic dilation should only be done on pts where rescue surgery can be safely pursued, since perf risk is 5%

pneumatic dilation and myotome are more durable tx, as compared to botox injections which are only effective for 6-12 months but are appropriate for pts who are not good surgical candidates. can also consider meds for poor surgical candidates

Question 11

what must you do before considering anti reflux surgery?

Answer 11

do esophageal manometry to rule out major motility disorders that would be contraindications for anti reflux surgery or post high risk for postoperative dysphagia

anti reflux surgery would pose high risk of postoperative achalasia in pts w/ absent contractility or scleroderma

Question 12

why do we recommend low fiber low fat diet for gastroparesis patients?

Answer 12

fat and fiber slow gastric emptying

Question 13

what is dumping syndrome?

Answer 13

a potential complication of gastric surgery resulting from rapid emptying of hyperosmolar stomach content into the small bowel

occurs in up to 50% of post-gastric bypass pts, especially after consuming foods rich in simple carbs/hyperosmolar.

the hyperosmolar content results in rapid fluid shift from the plasma into the small bowel lumen –> hypoTN and sympathetic response

symptoms:
postprandial nausea, vomiting, fullness, abdominal cramps, and diarrhea w/ diaphoresis, lightheadedness, palpitations, and flushing

Question 14

how do you tx dumping syndrome?

Answer 14

primary, dietary changes:

• multiple small meals
• avoid simple sugars
• increase dietary fat and fiber
• separate taking liquids and solids (i.e. no liquids 30 min before and after meals)

can also use octreotide

Question 15

rate the types of achalasia in order of highest to lowest treatment efficacy

Answer 15

type II (highest treatment efficacy)
type I
type III

Question 16

True or False.

graded pneumatic dilations and surgical myotome have been found to have similar treatment response at 5 yrs

Answer 16

True

per the European Achalasia Trial

Question 17

what is the proposed mechanism of buster for functional dyspepsia?

Answer 17

buspar improved fundi accommodation

Question 18

what cutoff for symptom-reflux correlation/symptom index on pH/impedance testing suggests significant correlation?

Answer 18

a symptom index (# of correlated episodes / # of reported heartburn events) of 0.5 suggests significant correlation

Question 19

True or False.

Baclofen relaxes LES

Answer 19

False.

Baclofen has been shown to increase basal LES pressure and decrease transient LES relaxation.

Therefore, baclofen may play a role as an anti reflux agent.

Question 20

what is the pathophys of urge fecal incontinence?

what will you see on anorectal manometry?

Answer 20

the external anal sphincter (EAS) reflexively contracts during actions associated with increased intraabdominal pressure (coughing, laughing) to maintain continence.

It is also under voluntary control to “hold” when an urge to defecate is felt.

urge fecal incontinence is likely due to weakness of the external anal sphincter.

On ARM, you will see low anal sphincter squeeze pressure (which measures voluntary contraction of the external anal sphincter)

Question 21

what defect is suggested by passive stool leakage without sensation?

Answer 21

a weakness of the internal anal sphincter or resting tone, characterized by decreased anal sphincter resting pressure

Question 22

what is the “ideal brake”

Answer 22

the presence of fat in the ileum delays gastric emptying

Question 23

what are the excitatory motor neurons and inhibitory motor neurons of digestive peristalsis?

Answer 23

excitatory motor neurons:
substance P, acetylcholine

inhibitory motor neurons:
nitric oxide, VIP

Question 24

what is the fasting motility pattern of the small intestine?

Answer 24

the migrating motor complex (MMC) travels from the proximal to distal small bowel in 90-120 minute cycles (another question says 75-90 min cycles)

the MMC clears residual chyme from the DISTAL stomach to the cecum

the MMC is partially regulated by motion and it is composed of 4 phases

Question 25

What comprises small intestine motility in the fed state?

Answer 25

2 processes - segmentation and peristalsis

SEGMENTATION:
localized contraction at multiple levels simultaneously
no forward movement
purpose is to mix and chop chyme w/ digestive enzymes

PERISTALSIS
slow, coordinated contraction for forward propulsion
balance of excitatory (substance P, acetylcholine) and inhibitory (nitric oxide, VIP) motor neurons

Question 26

define gastroparesis as per gastric emptying study criteria

Answer 26

gastric retention >10% at 4 hrs

and/or

gastric retention >60% at 2 hrs

this assumes using the standard low fat, scrambled egg meal

Question 27

what is the classic triad in patients with hyperemesis cannabis syndrome?

Answer 27

• cyclic vomiting
• chronic marijuana use
• hot showers to relieve symptoms

hyperemesis cannabis syndrome should not be confused w/ cyclic vomiting syndrome

Question 28

what are the most common causes of non cardiac chest pain?

Answer 28

• GERD
• esophageal motor disorders
• functional chest pain (dx requires ruling out major esophageal motor disorders)

Question 29

what esophageal motor disorders are associated w/ GERD?

Answer 29

weak LES and ineffective esophageal motility (IEM)

Question 30

what anatomical defect is responsible for dysphagia lusoria?

sx?

Answer 30

dysphagia lusoria is 2/2 aberrant R subclavian artery

symptoms include solid food dysphagia a/w regurgitation of unthawed food, postprandial bloating, chest pain, and sx that may change w/ position

Question 31

what types of esophageal abnormalities can result from the following systemic/autoimmune diseases?

polymyositis
diabetes
SLE
scleroderma

Answer 31

polymyosiits
affects swallowing by involving the striated muscles of the pharynx and upper esophagus

diabetes
nonspecific motor abnormalities of the esophagus

SLE
nonspecific motor abnormalities of the esophagus

scleroderma
solely affects the distal 2/3 smooth muscle of the esophagus

*** remember, scleroderma solely affects the SMOOTH MUSCLE of the GI tract

Question 32

what is the cutoff for an abnormal sitz marker study?

Answer 32

the sitz marker study is abnormal if there are more than 5 markers retained in the colon on day 5 after ingestion

Question 33

chronic opiate use has been associated w/ which esophageal motor disorders?

Answer 33

opiates have been associated w/

• esophagogastric junction outflow obstruction
• achalasia (not type 1)
• other hyper contractile esophageal abnormalities

Question 34

what is the most common cause of gastroparesis?

which symptoms best correlate w/ severity of gastric emptying?

Answer 34

idiopathic gastroparesis

early satiety and postprandial fullness correlate better w/ gastric emptying (as compared to abdominal pain and bloating)

Question 35

when considering gastric emptying study for diabetics, what condition would preclude performing the study?

Answer 35

do not do gastric emptying study in diabetics w/ glucose >275

Question 36

if a pt w/ scleroderma has anorectal involvement, what effect does that have?

Answer 36

scleroderma only affects the smooth muscle of the GI tract

the internal anal sphincter is completely smooth muscle. therefore, anorectal involvement of scleroderma causes low anal resting pressure BUT WILL SPARE THE EXTERNAL ANAL SPHINCTER (which is made of striated muscle)