Motility disorders of the GI tract - Paul MK Flashcards
Gastroparesis
“Stomach paralysis” –> impairment of food transit W/O obstruction. Syndrome with many causes.
Functional dyspepsia
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
Esophageal Manometry. What is it.
Measures the pressure in the esophagus using a tube run through the nose and down through the nasopharynx.
What is the criteria for a positive gastric emptying study? How is it performed?
Eat radioactive eggs.
Abnormal: retention >60% at 2 hr or >10% at 4 hr
What defines a neuropathic cause of decreased gastric motility?
Damage to the enteric nervous system. (any cause)
Myenteric plexus or submucosal plexus.
What defines a myopathic cause of decreased gastric motility?
What might be some examples?
Diseased gastric muscles. Can be due to a genetic defect (dystrophy), or acquired (scleroderma)
What is achalasia? What are the hallmarks?
Patient may have dysphagia and heartburn.
Hallmarks: Absence of peristalsis and no lower esophageal sphincter (LES) relaxation
What is the principal pathological abnormality of scleroderma?
high yield.
Smooth muscle atrophy and gut wall fibrosis
Motility issues everywhere in the GI tract.
[Scleroderma is a small vessel vasculitis]
What type of process is scleroderma?
Myopathic
What are some symptoms of scleroderma?
Dysphagia due to absence of peristalsis.
GERD due to lack of contraction of the esophageal sphincter.
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?
Noncholinergic. There are more of these near the LES.
What is receptive relaxation? What mediates it?
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.
Liquid emptying of the stomach occurs by:
tonic pressure gradient
Solid emptying of the stomach occurs by:
vagally mediated contractions.
What symptom might a lung transplant lead to, and why?
Severing of part of the vagus leads to gastroparesis. This would be an example of a neuropathic cause of gastric immotility.
Imaging shows dilation of the small bowel without occlusion. What is the likely condition?
What is a complication?
Chronic Intestinal Psuedo-Obstruction (CIPO)
Stasis–> bacterial overgrowth –> fermentation and malabsorption–> bloating
NOTE: this is a syndrome, so it can have many causes.
An infant born with CIPO will not survive past one year of age, generally. True or false.
False. 1/3 of infants die before the age of 1
What are the two types of peristalsis in the colon?
Haustra–> low amplitude and rhythmic–> mixing
High Amplitute Propagated Contractions (HAPCs) for expulsion.
Name three things that increase colonic motility.
Coffee
Waking up
Eating
Diabetes. Constipation or diarrhea?
Constipation
Scleroderma. Constipation of diarrhea
Constipation
Hirschprungs. Constipation or diarrhea/
Constipation.
How is the Sitz test performed? What defines normal/abnormal.
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
What is the fundamental defect in Hirschprungs disease?
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
