The motility of the stomach is initiated in the pacemaker region of the stomach which is in the _______
fundus. Waves then propagate toward the pylorus
How frequently does the stomach contract?
about once every 20 seconds or 3x/min
Note about movement of food through the stomach
peristaltic waves push food from the fundal region into the plyoric region where at most times the pyloric sphincter is constricted to almost produce retrograde movement and continue to break down food until it is small enough to pass through the pylorus into the duodenum
What is gastric accommodation?
ingestion of food is associated with distension of the stomach fundus/body from abotu 200ml to about 500ml
Describe gastric emptying
At 60 minutes most of the food is still in the fundus (~80%), 30-40% at 2 hrs and, and by 4 hrs the vast (95%) majority as passed out of the stomach
Below is a normal solid meal
In contrast, liquids pass much more quickly through the stomach with 50% being passed in about an hour
What is gastroparesis?
delayed gastric emptying NOT caused be mechanical obstruction
What are the cardinal symptoms of gastroparesis?
early satiety (60-86%),
abdominal pain (46-90%)- probably not the primary symptom
weight loss as the condition becomes more severe
What are some main causes of gastroparesis?
-idiopathic (most common)
-Infiltrative processes (scleroderma, amyloidosis)
Dysautonomia (diabetic or amyloid neuropathy)
-CNS disorders (stress, Parkinsonism, MS, etc.)
What are some medications that can delay gastric emptying?
Up to 50% of all cases of gastroparesis are due to _______
How common is gastroparesis in diabetics?
Up to 30-60% of type I diabetics will develop GP after longstanding disease while
up to 30% of type II diabetics will
What part of diabetes caused gastroparesis?
The entire pathogenesis is not completely understood but it is partially due to neuropathy and hyperglycemia itslef can delay gastric emptying
What surgeries most commonly lead to gastroparesis?
fundoplication (an anti-reflux surgery)
How can a mechanical obstruction be eliminated from the Ddx in pts with suspected gastroparesis?
usually via an upper endoscopy
or CT or barium studies
What is this?
gastric outlet obstruction (stenosed pylorus)- not technically gastroparesis. This is usually due to an ulcer and can actually be dilated at the time of the procedure or may be treated with a PPI
What is this?
barium study showing gastric outlet obstruction. Usually followed by endoscopy
Notice how much the stomach is dilated
What is the test of choice to make the diagnosis of gastroparesis?
a gastric emptying study
Typically, the 4hr is more important
What things need to be on the differential for gastroparesis?
-cyclic vomiting syndrome
What is rumination disease?
Rumination syndrome, or Merycism, is an under-diagnosed chronic motility disorder characterized by effortless regurgitation of most meals following consumption, due to the involuntary contraction of the muscles around the abdomen. There is no retching, nausea, heartburn, odour, or abdominal pain associated with the regurgitation, as there is with typical vomiting. The disorder has been historically documented as affecting only infants, young children, and people with cognitive disabilities (the prevalence is as high as 10% in institutionalized patients with various mental disabilities). Today it is being diagnosed in increasing numbers of otherwise healthy adolescents and adults, though there is a lack of awareness of the condition by doctors, patients and the general public.
Dietary management of gastroparesis
High fat diets will delay gastric emptying
Pharm management of GP
What is Metoclopramide?
A dopamine receptor 2 antagonist that enhances gastric antral contractions
5-20 mg QID. Approved for use up to 12 weeks
What limits Metoclopramide use?
Side effects are seen in up to 30% of users including:
drowsiness, fatigue, agitation and hyperprolactinemia (galactorrhea, amenorrhea, etc.). These are reversible
tardive dyskinesia in 1-10% of pts. when taken 3+ months (irreversible)
What is Domperidone?
a dopamine 2 antagonist (not readily available in the US). 10-20 mg TID
Can prolong the QT interval