Motility Disorders of the GI Tract Flashcards
Broadly, what causes motility disorder?
- Missing enteric nervous input
- Disease GI muscles (can be genetic defect or progressive sclerosis)
- Abnormal pacemaker cells (the interstitial cells of Cajal)
- CNS disorders
Achalasia is __________________.
absence of esophageal peristalsis
Progressive systemic sclerosis presents with what GI findings?
Smooth muscle atrophy (leading to weak peristalsis , GERD, and dysphagia) and gut wall fibrosis
––– predominantly a myopathic process
Where are the interstitial cells of Cajal?
In the proximal body along the greater curvature of the stomach
What is the role of the fundus?
It relaxes in response to food intake, thus allowing you to eat a big meal.
Which part of the stomach does the processing?
The distal stomach, near the antrum
What nerve mediates receptive relaxation and distal grinding?
The vagus nerve (in response to LES relaxation); hence, patients with vagotomies often have failure of gastric accommodation.
Define gastroparesis.
(n.) stomach paralysis; can be caused by muscle weakness or obstructive disorders
What percent of radiolabeled EggBeaters is considered abnormal retention?
- Greater than 60% at two hours
- Greater than 10% at four hours (greater than 35% is considered severe)
What is the hallmark of GI motility disorders?
Intestinal pseudo-obstruction – signs/symptoms of intestinal obstruction without a lesion obstructing flow of intestinal contents
What major small intestine complication should you worry about in someone with chronic intestinal pseudo obstruction?
Stasis can lead to bacterial overgrowth, which can lead to malabsorption, fermentation
CIPO has a ___________ prognosis in children. What usually causes it?
poor (1/3 die before age 1!); it is generally congenital
Low-amplitude contractions in the colon produce ________________.
mixing
High-amplitude contractions in the colon produce _______________.
propulsion
Describe the process of Sitz markers.
You give someone a capsule containing 24 radio opaque capsules and then x-ray their abdomen five days later; less than five markers is considered normal. It is used to evaluate colonic transit.
What causes Hirschsprung’s?
Congenital absence of the myenteric neurons of the distal colon, resulting in absence of the inner-anal sphincter reflex. (It’s normally supposed to relax in response to arrival of feces.)
Small frequent meals low in insoluble fiber and fats is a treatment for ________________.
gastroparesis
Describe the setup for recording esophageal manometry.
It is a nasogastric catheter placed down the esophagus that records pressure every one centimeter while the patient swallows water.
Achalasia results from ________________.
inflammatory destruction of the myenteric nerve plexus of the esophagus – predominantly the nitric-oxide-producing inhibitory neurons (sparing the cholinergic excitatory)
True or false: achalasia usually presents suddenly.
False. The progression is gradual, with many patients not seeking treatment until years of symptoms.
What percent of patients with scleroderma have GI involvement?
90
How can you resolve scleroderma and achalasia?
Those with scleroderma usually have a weak LES pressure, while those with achalasia have a normal or even overactive LES pressure.
Contrast the roles of the proximal and distal portions of the stomach.
Proximal: relaxes in response to filling so as to accommodate meals
Distal: contracts to mechanically grind food; empties into the duodenum
What are some classic causes of gastroparesis?
- Vagotomy
- Diabetes (autonomic neuropathy)
- Medications
- Neurologic disorders (MS, Parkinson’s, stroke)
True or false: the MMC phases occur in transplanted small bowel.
True. Only the enteric nervous system is needed; extrinsic innervation (i.e., the vagus nerve) is not needed
Chagas disease (Trypanosoma infection) can lead to what bowel problem?
Chronic intestinal pseudo-obstruction
Most of the colonic contractions are which type of movement?
Segmental (95%)
Peristaltic (5%)
The _____________ reflex is lost in those with Hirschsprung’s.
internal anal sphincter relaxation
What is the characteristic pattern of neuropathic small-bowel disorders?
Normal amplitude contractions, but uncoordinated
Increased frequency of MMC
Biofeedback therapy is helpful for ____________.
dyssynergia
