Motility Disorders of the GI Tract

Question 1

What causes motility disorders?

Answer 1

ENS: missing, immature, damaged by infection, influenced by chemical substances; =Neuropathic

Diseased GI muscles: genetic defect (muscular dystrophy) or acquired (progressive systemic sclerosis) =Myopathic

Abnormalities of interstitial cells of Cajal– pacemaker

CNS disorders

Question 2

Achalasia

Answer 2

seen as absence of esophageal peristalsis and no LES relaxation

Question 3

Scleroderma/Progressive Systemic Sclerosis (PSS)

Answer 3

Multisystem disorder:

• obliterative small vessel vasculitis
• Connective tiss proliferation w/ fibrosis of multiple organs

GI manifestations in 80-90%
GI abnormalities: smooth muscle atrophy and gut wall fibrosis (thus a myopathic process)

Esophageal manifestations:
smooth muscle atrophy–>weak peristalsis–>dysphagia
SM atrophy–>weak LES–>GERD
Unrepentant GERD–>Esophagitis–>stricture

Question 4

How do you dx esophageal disease?

Answer 4

esophageal manometry

seen with Scleroderm/PSS

Question 5

Spastic Disorders of the esophagus

Answer 5

• conditions of uncertain etiology
• peristalsis PRESERVED
• Sx: chest pain, dysphagia
• poss pathophys: overactivity of excitatory nerves or overreactivity of smooth muscle response

Question 6

physiology of gastric emptying

Answer 6

• receptive relaxation (vagally mediated inhibition of body tone)
• liquid emptying by tonic pressure gradient
• solid emtying by vagally mediated contractions
• residual solids emptied during non-fed state MMC every 90-120 mins

Question 7

Gastric Motility

Answer 7

Gastric pacemaker:

• interstitial cell of Cajal?
• proximal body along greater curvature

Fundus and proximal body:
storage

Distal body and antrum
-processing and emptying

Question 8

Receptive relaxation

Answer 8

swallowing induced vagal response

Question 9

accomodation

Answer 9

• smooth muscle relaxation elicited by mechanical distention of the stomach (Gastric mechanoreceptors)
• vasovagal response

Question 10

Dyspepsia

Answer 10

• discomfort or pain centered in the upper abdomen usually related to eating
• postprandial heaviness, early satiety, epigastric pain or burning

Organic: PUD, atypical GERD, gastric/esophageal cancer, pancreatico-biliary disorders, food/drug (NSAIDs) intolerance

Question 11

Functional dyspepsia

Answer 11

dyspepsia without organic etiologies

-40% w/ FD will have impaired gastric accommodation

Question 12

Gastroparesis

Answer 12

“stomach paralysis”

• impaired transit of food from the stomach to the duodenum
• Mechanical obstruction of the gastric outlet excluded

Question 13

Clinical Manifestations of gastroparesis

Answer 13

n/v, early satiety, postprandial abdominal distention or pain

Question 14

Major causes of gastroparesis

Answer 14

idiopathic (?post infectious)
post surgical (vagal nerve injury): gastric, esophageal, thoracic surgical procedures (lung transplant)
Diabetic
Meds (opiates)
Others: paraneoplastic, rheumatologic, neurologic, myopathic (Scleroderma)

Question 15

Dx of gastroparasis

Answer 15

-Gastric emptying study
gastric scintigraphy
Low fat EggBeaters w/ radiolabel
abnormal: retention >60% at 2 hr or >10% at 4 hr

Question 16

Management of gastroparesis

Answer 16

Lifestyle/dietary: small and infrequent meals, low fat and low residue diet, glucose control in diabetics

Meds:
Prokinetic agents, antiemetics

Gastric electric stimulation

Surgery ~2%

Question 17

Small Intestine motility fed vs fasted

Answer 17

-in fed state: primary motility is segmentation
-9-12 contractions/min (pacemaker cells)
-transit time 3-5 hrs
-Fasted state: Migrating motor complex: sequential orderly short peristaltic waves
stomach–>caudally
sweep gut b/t meals

Question 18

Small bowel motility disorders

Answer 18

Neuropathic:

• normal amplitude, but sustained bursts of uncoordinated phasic contractions
• early return and increased freq of MMC (can be bad because decrease absorption and can overwhelm the colon)

Myopathic:
decreased amp of contractions or lack of any motor activity

some diseases show both

Question 19

Chronic Intestinal Pseudo-Obstruction (CIPO)

Answer 19

• signs/sx of mech obstruction of SI w/o lesion obstructing flow
• dilation of the bowel on imaging
• major manifestation of SI dysmotility
• SI bacterial overgrowth =complication of CIPO: stasis–> bacterial overgrowth–>fermentation and malabsorption

Sx: n/v, abd pain, distention, constipation, diarrhea, urinary sx

Question 20

What might you see in myopathic forms of CIPO?

Answer 20

hypoactive motility

Question 21

Etiology of Small Intestinal Motility Disorders (and CIPO)

Answer 21

Neuropathic:

• degenerative neuropathies (eg Parkinson’s)
• Paraneoplastic Autoimmune (anti-Hu ab)
• Diabetes associated (neuropathy)
• Chagas Disease: parasite Trypanosoma cruzi

Mixed myopathic and neuropathic:

• infiltrative conditions: **Scleroderma, amyloidosis, eosinophilic gastroenteritis
• idiopathic

Question 22

CIPO in kids

Answer 22

• mostly congenital
• mostly primary condition (visceral neuropathy/myopathy)
• absent MMC predicts need for IV nutrition
• one third of infants born die in 1st year of life

Question 23

Two types of motor activity in Colon

Answer 23

• low amp tonic and phasic contractions for mixing luminal contents (Haustra)
• high amp propagated contractions (HAPCs) for propelling

Question 24

Causes of constipation

Answer 24

drugs
mechanical
metabolic: *DM, hyopK, hyperCa, hypoMg, hypothyroid
Myopathy: amyloid, scleroderma
Neurogenic: Parkinson’s, spinal cord injury, MS, autonomic neuropathy, Hirschsprung’s
Other: preg, immob
IBS-C
Normal transit, slow transit, dyssynergic defecation

Question 25

Colonic Transit studies

Answer 25

``` Sitz marker (get XR day 5; >5 markers in recto-sigmoid= defecatory disorder; >5 throughout colon =slow transit) Scintigraphy (dissolves in alkaline distal ileum, scans 4, 24, 48 hrs show colonic distrib) wireless capsule ```

Question 26

Evaluation of incontinence

Answer 26

-anal manometry | resting and volitional squeeze, cough reflex test, rectal sensation testing

Question 27

Eval of constip

Answer 27

-anal manometry anal resting pressure, attempted defectation lying left lateral, simulated defecation w/ 50cc balloon, rectoanal inhibitory reflex (absent in Hirschsprung's), rectal sensation testing

Question 28

Hirschsprung's Disease

Answer 28

- congenital absence of myenteric neurons of the distal colon (Neuropathic motility disorder) - no reflex inhibition of the IAS following rectal distention (***no recto-anal inhibitory reflex)

Question 29

internal and external anal sphincter muscle, puborectalis muscle

Answer 29

IAS: circular smooth; autonomic innervation: pelvic plexus EAS: striated volitional innervation: pudendal nerve Puborectalis muscle: striated--volitional (helps form anorectal angle; w/ contraction and descent of pelvic floor-->decreased angle)

Question 30

Pelvic floor dysfunction

Answer 30

- inability to coordinate the abdominal, rectoanal, and pelvic floor muscles during defecation - anismus (high anal resting pressure) - incomplete anal relaxation - paradoxical contraction of pelvic floor and EAS (*dyssynergia) - rectal hyposensitivity - excessive perineal descent - rectocoele Causes: bad toilet habits, painful defecation, obstetric or back injury, brain/gut dysfunction

Question 31

Dx of Dyssynergia

Answer 31

-abnormal anorectal manometry -reveals: paradoxical contraction of pelvic floor and EAS Tx: biofeedback therapy is effective

Question 32

Alteration of esophageal peristalsis

Answer 32

achalasia | scleroderma

Question 33

Alteration of LES relaxation

Answer 33

achalasia

Question 34

Alteration of LES tonic contraction

Answer 34

scleroderma

Question 35

Alteration of gastric receptive relaxation/accomodation

Answer 35

functional dyspepsia

Question 36

Alteration of gastric emptying

Answer 36

gastroparesis, functional dyspepsia

Question 37

Alteration of small bowel motility (peristalsis)

Answer 37

CIPO (scleroderma) altered SI motility w/ underlying neuropathic cause: DM, primary pediatric visceral neuropathy w/ underlying myopathic: scleroderma, amyloidosis, primary pediatric visceral myopathy

Question 38

Alteration of colonic tranist

Answer 38

slow transit constipation (scleroderma)

Question 39

Alteration of sphincter function

Answer 39

Hirschsprung's | Dyssynergic defecation

Question 40

Esophageal manometry can dx

Answer 40

achalasia | scleroderma

Question 41

Gastric emptying study (gastric scintigraphy) can dx

Answer 41

gastroparesis

Question 42

Anal manometry can dx

Answer 42

Hirschsprung's | Dyssynergic defecation