Motility Disorders of the GI Tract Flashcards
How is Esophageal motor function assessed on esophageal manometry
By the amplitude and propagation of the pressure waves. These two parameters can be used to determine the presence and success rate of peristalsis.
Describe esophageal manometry .
This test is performed using a transnasal, intraluminal catheter containing pressure sensors spaced closely together (1cm apart). Once positioned from the nares into the stomach, assessment of esophageal motility is made as patient swallows repeated small boluses of water.
Achalasia is the prototypical esophageal motility disorder. Achalasia results from inflammatory destruction of neurons in the _______ of the esophagus
myenteric plexuses
Loss of inhibition at the (lower esophageal sphincter) LES leads to the cardinal defect in ______ , the failure of appropriate LES relaxation after swallowing
achalasia
what are the diagnostic findings in achalasia
Diagnostic findings are incomplete relaxation of the (LES) aperistalsis in the smooth muscle esophagus, seen on Esophageal manometry
Scleroderma is associated with:
alterations of the microvasculature, the autonomic nervous system, and the immune system with a downstream consequence of fibrosis
describe why 90% of patients with scleroderma have GI tract involvement.
Small vessel vasculitis -> vascular derangement -> smooth muscle atrophy -> fibrosis. The entire smooth muscle section of the GI tract is susceptible
how can Scleroderma be distinguished from achalasia
presence of a weakened lower esophageal sphincter pressure in scleroderma (as opposed to a hypertensive LES with failure to relax after swallowing in achalasia).
what are the 3 esophageal manifestations of scleroderma
1) dysphagia (difficulty swallowing)
2) GERD
3) Esophageal stricture (chronic GERD)
what are the symptoms of Spastic Disorders of the Esophagus
Chest pain and difficulty swallowing
Manometric abnormalities of spastic disorders
1) swallows associated with dramatically increased contractile vigor (high pressures over a broad esophageal length and for a long duration)
or
2) rapid/premature esophageal peristalsis (contraction of the esophagus that occurs to rapidly after initiation of a swallow).
The 3 major digestive functions of the stomach are:
- Storage of large amounts of food. The volume of the stomach can vary between about 50ml in an empty state to nearly 1500ml after eating.
- Mechanical breakdown of larger particles into smaller particles (< 2 mm), known as chyme.
- Slow delivery of chyme to the duodenum at a rate not to exceed the digestive and absorptive capacity of the small intestine.
Gastric peristalsis originates in the ‘pacemaker-cells’ (_______) in the mid-portion of the body, and travel distally towards the pylorus at a frequency of about 3/minute
interstitial cells of Cajal
what is Gastroparesis
a disorder of delayed gastric emptying in the absence of mechanical obstruction.
what are the 7 classic symptoms of gastroparesis
early satiety, bloating, nausea, anorexia, vomiting, abdominal pain, weight loss
name 5 Common causes of gastroparesis
diabetes,
medications,
prior gastric or thoracic surgery (potential vagal injury), post-viral state
some neurologic or infiltrative disorders.
When Scleroderma affects the stomach, delayed gastric emptying may result. As with the esophageal dysmotility seen in scleroderma this is related to _______
smooth muscle fibrosis.
what is Receptive relaxation?
Swallowing-induced vagal response that relaxes the stomach (fundus and proximal corpus) facilitating food storage, allowing an increase in volume up to 15 times its empty state with very little increase in intragastric pressure
how is Gastroparesis Diagnosed
scintigraphic gastric emptying (AKA a gastric emptying study)
describe the scintigraphic gastric emptying (AKA a gastric emptying study)
technetium labeled egg (or substitute) is eaten as part of a standardized meal and the percentage of radiotracer left in the stomach after 4 hours is measured. Gastroparesis is described as mild, moderate or severe based on the percentage of the meal remaining (> 35% is severe gastroparesis).
Describe accomodation
Smooth muscle relaxation elicited by mechanical distention of the stomach (Gastric mechanoreceptors)
define Dyspepsia
Discomfort or pain centered in the upper abdomen
what are the Sx’s of dyspepsia
postprandial heaviness,
early satiety,
epigastric pain or burning
what is Functional Dyspepsia
When there’s dyspepsia and no organic etiologies
what are 5 causes of dyspepsia
Peptic Ulcer Disease (PUD), atypical GERD, gastric/esophageal cancer, pancreatico-biliary disorders, food/drug (NSAIDs) intolerance
40% of FD patients have impaired ________
gastric accommodation
what is a smart pill?
Ingested capsule that wirelessly measures:
Temperature
pH
Pressure
what can a smart pill assess?
Gastric emptying
Small bowel transit time
Colonic transit time
what medications are used in MGMT of gastroparesis
Prokinetic agents
Antiemetics
what is the Migating Motor Complex
Occurs during Fasting State
Sequential orderly short peristaltic waves
Stomach -> Caudally
Sweep gut between meals
Characterize Small intestinal pseudo-obstruction
signs and symptoms of a mechanical obstruction of the small or large bowel in the absence of an anatomic lesion that obstructs or partially blocks the flow of intestinal contents.
Pseudo-obstruction may be acute or chronic (CIPO) and is characterized by the presence of _______ on
imaging.
dilation of the bowel
When there is evidence of chronic small intestinal motility disorder in the absence of bowel dilatation, the preferred term is ________
chronic intestinal dysmotility.
what are the 3 most common Sx’s of CIPO
1) nausea/vomiting
2) Abd. Pain
3) Distention
To maximize time for reabsorption, most colonic motility (approximately 95% of contractions) is ________
nonperistaltic
what are the major constipation cause highlighted in class
DM, Amyloid, Scleroderma Hirschsprung’s dyssynergic defecation
Descibe a sitz marker study
A capsule containing 24 radioopaque markers is swallowed by the patient and an abdominal X-ray is obtained after 5 days. Less than 5 markers left in the colon is considered normal.
describe the abnormal results from a Sitz study and what they mean
> 5 markers in recto-sigmoid suggests defecatory disorder
>5 markers scattered throughout colon = slow transit
describe a scintigraphy as it relates to colonic transit studeis
Isotope in delayed-release capsule dissolves in alkaline pH of distal ileum
Gamma camera scans in 4,24, and 48 hours to show colonic distribution
The reflex of stool causing distention of the rectum leading to internal anal sphincter relaxation is termed the _______ reflex (which is absent in _______ disease).
recto-anal inhibitory,
Hirschsprung’s
describe anorectal manometry
A catheter with pressure sensors (similar to esophageal manometry) is placed traversing the anus and rectum. Resting pressure, simulated defecation, rectal sensation testing and recto-anal inhibitory reflex testing are all assessed.
Describe Hirschsprung’s Disease
Congenital absence of myenteric neurons of the distal colon (always involving the internal anal sphincter). Results in lack of reflex inhibition of the internal anal sphincter following rectal distention. Anorectal manometry reveals absence of recto-anal inhibitory reflex.
Describe dyssynergic defection
Disorder on coordination of pelvic floor musculature. Anorectal manometry reveals paradoxical contraction of the pelvic floor and external anal sphincter with attempts at defecation.
what is the Tx of dyssynergic defection
Biofeedback (essentially re-learning how to have a bowel movement is effective).
