Esophageal Motility, Achalasia: Ismail

Question 1

Name the two plexuses comprising the enteric nervous system and their respective locations.
Finally, define their respective functions.

Answer 1

Myenteric plexus- btwn circular and longitudinal muscular layers :: control contractility of muscles.
Meissner plexus- submucosa :: control secretions

Memory aid: Meissner’s corpuscles (light touch sensation) are located in dermal papilla (dermis is analogous to submucosa)

Question 2

Pacemaker cells that control the rate/rhythm of peristalsis are aka:
Are they neuronal in origin?
Where are they found?

Answer 2

interstitial cells of Cajal (pacemaker cells)
Not neuronal in origin
Found throughout GI tract

Question 3

Lower esophageal sphincter relaxation is controlled by:

Answer 3

Vagus nerve- biggest player is nitric oxide

Question 4

Describe the types of peristalsis and their roles in passing food down the esophagus.

Answer 4

Primary peristalsis- reflex esophageal peristaltic contraction wave associated with swallowing.

Secondary peristalsis- clears residual food left behind by ineffective primary peristalsis.

Tertiary peristalsis- non peristaltic contractions. Usually pathologic.

Question 5

Describe the rate of contractions of the stomach.

Answer 5

3 cycles/min

Question 6

What is the function of the migrating motor complex (MMC)?

Describe its 4 phases.

Answer 6

Sweeping function, house keeping. Clears residual waste down length of tract. Keeps small bowel as sterile as possible.
Phase I- motor quiescence (40-60%) :: most time spent here
Phase II- increasing but irregular contraction (20-30%)
Phase III- intensive rhythmic contraction (10%)
Phase IV- transition from phase III back to I (0-5%)

Question 7

What is achalasia? 
Incidence?
Etiology?
Pathology?
Histology?
Symptoms?

Answer 7

Failure of the lower esophageal sphincter to relax upon swallowing.
1:100,000
Unknown etiology- autoimmune, degenerative, infxn?
Pathology: Selective loss of postganglionic inhibitory neurons (no nitric oxide)
Histo: Lymphocyte infiltrate in myenteric plexus and loss of ganglion cells.
Symptoms:
Dysphagia 85-91%
Chest pain in area of xyphoid process 40%
Weight loss 60%
Heartburn 40%
Regurg. of food.

Question 8

What else are we worried about that could present with similar symptoms to achalasia, but would be differentiated on endoscopy?

Answer 8

Pseudoachalasia caused by malignancy- mass effect could block food passage down esophagus

Question 9

What is manometry and how is it used to Dx achalasia?

Answer 9

Monometry involves measurement of pressure using a special catheter.

Question 10

Describe the 2 manometric criteria required to dx achalasia.

Answer 10

Incomplete LES relaxation

Aperistalsis in body of esophagus

Question 11

Describe treatment for achalasia.

Answer 11

Primary tx: surgical or endoscopic therapeutic management- botulinum injection (vast majority), balloon dilation, Heller’s myotomy- muscl. of LES are cut, allowing food to pass, but sparing sphincter function.

If surgery/endoscopy fails:
Nitrates, CCBs (both relax smooth muscle)

Question 12

Describe complications of achalasia.

Answer 12

Malnutrition
Aspiration
Malignancy- SCC of esophagus

Question 13

Describe two conditions, one malignant and the other of infectious origin that results in enteric neuropathy, that result in achalasia-like motility dysfunction.

Answer 13

Malignancy- gastric cancer

Infectious- Chagas dz (T. cruzi)

Question 14

What is diffuse esophageal spasm (DES)?

Answer 14

Discoordinated motility.
Repetitive contractions (> 3 peaks) of prolonged duration
**frequent, high amplitude peaks on manometry**

Question 15

What is nutcracker esophagus?

Answer 15

Hypercontracting esophagus