Motility Flashcards
what is rectoanal inhibitory reflex (RAIR)?
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.
on anorectal manometry, what defines an absence rectoanal inhibitory reflex (RAIR)?
lack of anal sphincter relaxation with balloon distension in the rectum
what should an absent RAIR make you concerned about?
an absent RAIR should raise suspicion for Hirschsprung’s disease
what is Hirschsprung’s disease?
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
what is the major side effect of lubiprostone? what is it used to treat?
nausea is the major side effect of lubiprostone (amitiza). it is used to treat IBS-C
what is chronic intestinal pseudo-obstruction categories and how do you distinguish between them?
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.
what do you see for distal esophageal spasm on esophageal manometry?
an increased proportion of swallows (>20%) w/ decreased distal latency (<4.5 sec)
what do you see for Type II achalasia on esophageal manometry?
increased IRP w/ pan esophageal pressurization
also shows “bird’s beak” on esophagram
what is the perforation risk of pneumatic dilation of the esophagus?
5%
what is the first step in determining tx for achalasia?
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
what must you do before considering anti reflux surgery?
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
why do we recommend low fiber low fat diet for gastroparesis patients?
fat and fiber slow gastric emptying
what is dumping syndrome?
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
how do you tx dumping syndrome?
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
rate the types of achalasia in order of highest to lowest treatment efficacy
type II (highest treatment efficacy) type I type III
True or False.
graded pneumatic dilations and surgical myotome have been found to have similar treatment response at 5 yrs
True
per the European Achalasia Trial
what is the proposed mechanism of buster for functional dyspepsia?
buspar improved fundi accommodation
what cutoff for symptom-reflux correlation/symptom index on pH/impedance testing suggests significant correlation?
a symptom index (# of correlated episodes / # of reported heartburn events) of 0.5 suggests significant correlation
True or False.
Baclofen relaxes LES
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.
what is the pathophys of urge fecal incontinence?
what will you see on anorectal manometry?
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)
what defect is suggested by passive stool leakage without sensation?
a weakness of the internal anal sphincter or resting tone, characterized by decreased anal sphincter resting pressure
what is the “ideal brake”
the presence of fat in the ileum delays gastric emptying
what are the excitatory motor neurons and inhibitory motor neurons of digestive peristalsis?
excitatory motor neurons:
substance P, acetylcholine
inhibitory motor neurons:
nitric oxide, VIP
what is the fasting motility pattern of the small intestine?
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
What comprises small intestine motility in the fed state?
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
define gastroparesis as per gastric emptying study criteria
gastric retention >10% at 4 hrs
and/or
gastric retention >60% at 2 hrs
this assumes using the standard low fat, scrambled egg meal
what is the classic triad in patients with hyperemesis cannabis syndrome?
- cyclic vomiting
- chronic marijuana use
- hot showers to relieve symptoms
hyperemesis cannabis syndrome should not be confused w/ cyclic vomiting syndrome
what are the most common causes of non cardiac chest pain?
- GERD
- esophageal motor disorders
- functional chest pain (dx requires ruling out major esophageal motor disorders)
what esophageal motor disorders are associated w/ GERD?
weak LES and ineffective esophageal motility (IEM)
what anatomical defect is responsible for dysphagia lusoria?
sx?
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
what types of esophageal abnormalities can result from the following systemic/autoimmune diseases?
polymyositis
diabetes
SLE
scleroderma
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
what is the cutoff for an abnormal sitz marker study?
the sitz marker study is abnormal if there are more than 5 markers retained in the colon on day 5 after ingestion
chronic opiate use has been associated w/ which esophageal motor disorders?
opiates have been associated w/
- esophagogastric junction outflow obstruction
- achalasia (not type 1)
- other hyper contractile esophageal abnormalities
what is the most common cause of gastroparesis?
which symptoms best correlate w/ severity of gastric emptying?
idiopathic gastroparesis
early satiety and postprandial fullness correlate better w/ gastric emptying (as compared to abdominal pain and bloating)
when considering gastric emptying study for diabetics, what condition would preclude performing the study?
do not do gastric emptying study in diabetics w/ glucose >275
if a pt w/ scleroderma has anorectal involvement, what effect does that have?
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)
