136. GI Motility Disorders

Question 1

High Res Manometry

• what does it do
• define distal contractile integral (DCI), Distal Latency (DL), Integrated Relaxation Pressure (IRP)

Answer 1

GOLD STANDARD for esophageal motor fx
Shows pressure at various points from upper to LES (look at esophageal peristalsis

DCI: amplitude + direction of esophageal contraction (how much squeeze)
DL: peristalsis timing (how quick it moves)
IRP: LES inhibition (how much it opens)

Question 2

Achalasia

• definition
• pathogenesis
• endoscopy
• histo
• dx and types
• tx

Answer 2

IRP abnormally high and 100% FAILED peristalsis
Pathogenesis: ENS dysfx (loss of ganglion cells)
Endo: retention of food/saliva, esophageal dilation, EGJ constriction (LES does not open)
Histo: degeneration of myenteric neurons (inhibitory NO neurons), myenteric inflammation (only attacks esophageal enteric neurons)
Dx: progressive dysphagia/regurg of solids & liquids
Esophageal Manometry is key
Type 1: ABSENT contractile activity
Type 2: pan-esophageal pressurization
Type 3: Spastic Contractions

Tx: target LES!

• smooth muscle relaxants/BOTOX
• pneumatic dilation (stretch LES)
• per oral endoscopic myotomy (cut LES)
• esophageal stent
• percutaneous gastrostomy tube (bypass esophagus)
• Heller myotomy - cut LES, fundoplasty to prevent reflux

Question 3

EGJ Outflow Obstruction

• define
• pseudo-achalasia: define, mechanisms/types (3)
• secondary achalasia: types (3)

Answer 3

Abnormally high IRP but with peristalsis
Pseudo: mechanical obstruction mimicking GI dysmotility
Mechanisms: i. direct EGJ involvement, ii. submucosal infiltration of EGJ + muscularis with myenteric nerve destruction, iii. paraneoplastic syndrome (antibodies attack ENS) all SECONDARY TO CANCER (SCC esophagus, adenocarcinoma, gastric adenocarcinoma)

2o achalasia: 1. pseudoachalasia 2. Post-fundoplication (wrap stomach around esophagus to prevent reflux too obstructive), 3. Chagas’ Disease (trypanosoma cruzi) - reduviid kissing bug (mexico, central/south america) - chronic infection decades after acute infection (develop esophageal disorder)

Question 4

Gastroparesis

• sx, PE
• dx tests
• tx
• type of gastroparesis (pathogenesis)

Answer 4

sx: N/V, regurg, early satiety, weight loss, bloating, upper abd discomfort
PE: upper abd distention, succussion splash (slosh)
Dx: r/o gastric outlet obstruction (endoscopy), SCINTIGRAPHY (scan radiolabelled eggs to look at gastric emptying)
Tx:
- diet changes (frequent small meals, glycemic control in DM)
- Sx-based for N/V, GERD, Abd Pain (No OPIATES - cause more gastroparesis) - gastric pacing may help N/V
- Nutrition support (jejunal feeding tube)
- Prokinetic Drug (Metoclopramide - D2 antagonist; Prucalapride - 5HT agonist; Erythromycin - motilin antagonist; Domperidone - D2 antagonist (like metoclopramide but no CNS toxicity))

Diabetic Gastroparesis: due to autonomic vagal neuropathy - in pts w/ longstanding DM and additional sequelae (nephropathy, retinopathy, neuropathy), poor accommodation, decreased contractions, spasms

Question 5

Besides gastroparesis, list 2 other clinical diagnoses for gastric dysmotility

Answer 5

1. Post-surgical vagotomy - cut vagus nerve

2. Infantile Hypertrophic Pyloric Stenosis - smaller pyloric sphincter due to inflammation

Question 6

How does Scleroderma cause GI dysmotility? what is the pathogenesis of this? What can you see on imaging?

Answer 6

SSc: small bowel dysmotility in 20-25% pts
90% esophageal dysmotility (CREST)
initial event: neuropathic (impaired cholinergic transmission, antibodies against m3AChR)
Later event: visceral myopathy (smooth muscle atrophy, fibrosis)

Imaging: small bowel dilatation with STACKED COIN appearance of valvulae conniventes

Question 7

Small intestinal pseudo-obstruction

• sx
• clinical manifestations
• management

Answer 7

sx: abd bloating, pain, N/V/D, constipation/obstipation (2/2 bacterial overgrowth), weight loss, borborygmi (weird bowel sounds), excessive flatus
CM: maldigestion (impairment of food-enzyme mixing), small bowel bacterial overgrowth, small bowel diverticulosis (overgrowth, stasis, promotes more bacteria), pneumatosis cystoides intestinalis (PCI) - air into bowel wall

Mgmt

• diet: minimize hard to digest food, nutrition supplement, TPN
• rotating ABx to prevent overgrowth
• minimize drugs that slow motility (narcotics, CCBs)
• prokinetic agents (domeperidone, metoclopramide, prucalapride, octreotide - induce MMC phase 3 activity)
• avoid surgical tx

Question 8

Acute Colon Pseudo-obstruction (Ogilvie’s Syndrome)

• what is it
• sx
• pathogenesis
• tx

Answer 8

Hindgut ANS dysfx = marked colonic distention in ABSENCE of mechanical obstruction
95% assoc w/ underlying disorder (trauma, sepsis, cardiac disease, surgery)
sx: abd pain, N/V, SoB, obstipation (can’t move bowels)
Pathogenesis: imbalance of ANS (low parasymp, high symp)
Tx: remove + correct contributing cofactors (meds like narcotics, or causing hypoK, hypoMg)
- IV Neostigmine (AChE inhibitor)
- Colonoscopic Decompression +/- placement of colon decompression tube

Question 9

Hirschsprung’s Disease

• what is it
• dx
• tx

Answer 9

ENS Disorder, Congenital (1/5000)
Absence of enteric neurons in rectum and distal colon due to failed migration of neuroblasts into terminal bowel
dx: rectal biopsy (no ganglion cells, hypertrophic nerve fibers, high AChE activity)
tx: surgical resection of aganglionic segment