Koch: Motility Disorders Of Stomach And Sb

Front 1

Normal postprandial gastric neuromuscular work: emptying a solid meal

Back 1

First: fundic relaxation

Second: fundic contraction and emptying

Third: Corpus and antrum mill solid food into small particles (1-2mm)

Fourth: Antral peristalsis empties chyme through pyloris. Particles that are too large are sent back to stomach for more milling.

Fifth: Duodenal peristalsis (coordinated through antropyloroduodenal coordination)

Requires normal smooth muscle, enteric neurons, and ICCs

Front 2

Normal slow wave activity in body-antrum coordinates gastric peristalsis

Back 2

Gastric pacemaker

Slow waves (pacesetter potentials) from gastric pacemaker region on greater curvature of body at 3 cycles per minute
-Encircle stomach and then migrate distally toward pylorus
-Coodinate antral persitaltic waves

Plateau/action potentials linked to slow waves
-Create circular muscle contraction

Fundus has no to little rhythmicity

Front 3

Patterns for solid and liquid phase emptying

Back 3

Liquid
-50% retained (or emptied) at ~30 min
-Depends on caloric meal

Solid
-50% retained at 60 min
-Depends on consistency
-In general carbohydrates emptied faster than proteins which are emptied faster than fat (which releases CCK which tightens pylorus but relaxes corpus, therefore less emptying)
-After 4 hours should have less than 10% of food remaining in stomach

Front 4

Noninvasive clinical tests of gastric neuromuscular activities

Back 4

Scintigraphy--- isotope labelled foods

pH/motility capsule---ingested with test foods
-Has pH and pressure sensor
-Note how long it takes to exit pylorus

Electrogastrograms (EGG)---myoelectrical activity of the stomach
-Have patient drink water
-Look for electrical rhythm change
-Normal rhythm 2.5-3.7 cpm

Front 5

Gastric neuromuscular disorders (gastropathies) and symptoms

Back 5

Impaired fundic accomodation
-Early satiety

Abnormal electrical rhythm (not 3 cpm)
-Nausea

Hypomotility (<3 cpm)
-Prolonged fullness

Pylorospasm
-RUQ pain

Hypersensitive stomach (vagus sensitized)
-Nausea, pain, bloating

Front 6

Functional dyspepsia subgroup symptoms

Back 6

Unexplained nausea/vomiting PLUS:

Postprandial distress (predominantly nonpainful):
-Postprandial fullness
-Early satiation
-Nausea+; Bloating
-Chronic Idiopathic Nausea+

OR

Epigastric pain (predominantly painful):
-Localized epigastric pain/burning
-Intermittent
-No relief with defe-
cation or flatus

Front 7

Evaluation of patients with early satiety, N/V: mucosal vs neuromuscular disorders

Back 7

Empiric drug trials
-PPI, Prokinetic

Endoscopy
-Mucosal evaluation (make sure there is not mucosal abnormalities: esophagitis, duodenitis, gastritis)

Electrogastrogram and emptying time
-Category 1Abnormal EGG and abnormal GET: myoelectro-contractile abnormality
-Category 2: Abnormal EGG and normal GET: myoelectrical abnormality
-Category 3: Normal EGG and normal GET: nongastric cause
-Category 4: Normal EGG and abnormal GET: mechanical obstruction or electro-contractile dissociation

Front 8

Differential diagnosis for gastroparesis

Back 8

Obstructive gastroparesis 5%
-Will see huge 3 cpm waves
Ischemic gastroparesis <1%
-Will see slow cpm waves, but can be fixed surgically
Diabetic gastroparesis (type 1 and 2) ~30%
-High glucose damages ICC
-ICCs generate slow wave rhythm
Postsurgical gastroparesis ~20% (antrectomy, vagotomy, fundectomy, fundoplication)
-Injures vagus nerve
Miscellaneous Causes (collagen vascular disorders, amyloid, MD) <1%
Idiopathic gastroparesis (?postviral, ?drug-induced, ?degenerative or inflammatory processes-smooth muscle, enteric n., interstitial cells of Cajal, ANS)
-Largest category (~40%)

Front 9

Treatment approaches for gastric neuromuscular disorders

Back 9

Gastric Dysrhythmia and Gastroparesis (Severe Gastric Electro-Contractile Disorder)

Education

Drugs:
-metoclopramide (can convert tachygastria)---CNS side effects
-erythromycin---causes N&V
- BoTox injections(pylorus) ---? data
- ?grehlin agonist --- in development

Devices: G-tube/J-tube; gastric electrical stimulation (like a pacemaker)
-If nutritionally depleted

Regenerative Medicine Approaches
-Smooth muscle patches

Front 10

Nausea and vomiting gastroparesis diet

Back 10

Step 1: Gatorade and bouillion
-Salty with some caloric content to avoid dehydration

Step 2: Soups
-With noodles and rice
-PB, cheese, crackers,

Step 3: Starches, chicken, fish
-Noodles, pasta, potatoes, rice, baked chicken, fish

Low fat, low fiber

Front 11

Potential mechanisms for efficacy of gastric electrical stimulation

Back 11

1. Activation of afferent sensory pathways to CNS (thalamus/paraventicular nucleus) that “modulate” control mechanisms for nausea/vomiting
2. Enhancement of fundic relaxation (accommodation)
3. Enhance postprandial gastric slow wave ampl./velocity
4. Alteration of sympathovagal activity
5. Increase in gastric emptying (not consistent effect)

Front 12

Small bowel fasting vs fed patterns of motility

Back 12

Fasting pattern:
- Phase 1--- no contractions (10 min quiescence)
- Phase 2--- increased, random contractions (70 min)
- Phase 3 (migrating motor complex-MMC)---
-5-8 min of strong antral-duodenal contractions that migrate to ileum every 90-100 minutes

Fed pattern
- Segmental and short duration peristaltic contractions