Esophageal Dysmotility

A. Normal Esophageal Function [1]

Transport food to stomach: progressive peristalsis
Keep food in stomach: normal sphincter function
Swallowing
1. Progressive peristaltic contractions by circular muscle layers
2. Relaxation of sphincters at appropriate times
Determinants of flow
1. Flow = Delta(P/R) where Delta = change
2. P = pressure gradient and R = resistance
3. R = Viscosity / r4 where r = radius of tube
4. Thus, Flow = Delta (P·r4) / Viscosity
Flow Impairment (follows from above) from:
1. Decreased Delta(P) leads to reduced contractile force
2. Radius narrowing caused by tumor, varices, stricture
3. Viscosity increase due to poor chewing of food
Esophageal Manometry
1. Study changes during swallowing
2. Normally, esophagus is at rest with low pressure zones between sphincters
3. High pressure areas at lower and upper esophagus = sphincters
Control of esophageal muscle at biochemical level is being elucidated

B. Types of Motility Disorders [2]

Achalasia
Diffuse Esophageal Spasm
Hypercontracting Esophagus
1. Hypertensive Esophagus
2. Failed sphincter relaxation [3]
Hypocontracting Esophagus
1. Muscular Weakness
2. Muscular incoordination
Stenosis of esophageal lumen and/or luminal deformity
1. May be associated with cervical osteophytes
2. Diffuse idiopathic skeletal hyperostosis (DISH) patients often present with dysphagia [7]
Associated with irritable bowel syndrome
1. Functional abnormalities of esophageal motion
2. Poorly compliant esophagus with hyperreactivity may be underlying cause
Generalized Motility Disorders [3]
1. Hyperganglionosis - neuronal dysplasia, ganlioneuromatosis (MEN Syndrome 2B)
2. Hypoganglionosis - usually acquired (Chagas' Disease, Paraneoplastic Syndromes)
3. Various organ specific congenital diseases also exist
Common Symptoms of Dysmotility
1. Coughing and choking
2. Nasal regurgitation during eating implies a pharyngeal disorder
3. Dysphagia: spasm

C. Achalasia [2,4]

Features
1. Impaired swallowing induced relaxation of Lower Esophageal Sphincter (LES)
2. Absent esophageal peristalsis
3. Dysphagia to both liquids and solids
Patholgoy
1. Motor neuron defect
2. Usually due to damage to myenteric plexus
3. Unexplained degeneration of ganglion cells
Pathogenesis
1. Approximately 65% of patients with achalasia have autoantibodies against DARPP-32
2. DARPP-32 is a dopamine carrying protein on surface of myenteric plexus cells
Diagnosis
1. Lower esophagus is dilated with food held up, then with regurgitation
2. On barium swallow, lower esophagus fills with "parrot-beak deformity"
3. Thus, lower esophagus shows air-fluid level that fails to empty
4. Smoothly tapering obstruction of distal esophagus ("bird" or "parrot" beak deformity)
5. Esophageal manometry often shows elevated LES pressures (not always)
6. With swallowing, LES relaxation is incomplete
Treatment is usually with mechanical dilatation
1. Botulinum toxin injection to relax muscle may provide relief for ~6 months
2. Pneumostatic (balloon) dilatation is usually prefered but carries risk of perforation
3. Surgical myotomy - severing of muscles of LES - is secondary

D. Esophageal Spasm

Uncoordinated muscle contractions with loss of progressive peristalsis
Food stasis in segments leads to dysphagia with chest pain
Hypercontracting esophagus may have similar symptoms
Causes
1. Distal obstruction
2. Gastroesophageal reflux
3. Presbyesophagus (old age)
4. Ganglion degeneration
5. Idiopathic
Symptoms
1. Angina like chest pain [5]
2. Regurgitation of food
3. Sense of fullness in chest
4. Sour taste in mouth, reflux
Diagnostic Testing
1. Esophageal Manometry
2. Esophagogogram - may appear as corkscrew pattern
Treatment depends on cause [2]
1. Muscle relaxants: nitroglycerin, calcium channel blockers such as diltiazem
2. Acid reduction for gastroesophageal reflux
3. Improve contractions - metoclopramide
4. Trazadone or imipramine can also be helpful
5. Cisapride has been withdrawn from market due to prolonged QTc, cardiac arrhythmias [6]
6. Botulinum toxin
7. Dilation: static bougle, pneumoatic
8. Esophageal myotomy

E. Deformation and Stenosis of Lumen

Decreased maximal bolus size (usually can tolerate ~50% narrowing without symptoms)
Benign or malignant strictures
1. Both forms progress
2. Benign strictures, usually due to peptic ulcerations, progress slowly
3. Malignancy associated strictures usually associated with early weight loss
Congenital Rings
Aberrant vessels (for example, esophageal varices)
Schatzki's Ring
1. Common ring (~14% of population)
2. Found in lower esophagus
3. Do not progress
4. Usually present with anatomic obstruction, typically in age <35 years
5. Dysphagia, solids > liquids
6. Diagnosis and treatment with endoscopy
Treatment: Open Channel

F. Systemic Sclerosis (Scleroderma / CREST)

Muscle damage in esophagus, impaired contractility
Lower esphageal sphincter pressure is reduced
Gastroesophageal reflux causes stricture formation
CREST Syndrome
1. Esophageal hypomotility is prominent feature
2. Calcinosis, Raynaud's Phenomenon, Sclerodactyly, Telangiectasia
3. Disease is a variant of Systemic Sclerosis (Diffuse Scleroderma)
High dose H-2 Blockade usually not effective to control symptoms
Omeprazole (Prilosec®) is the preferred agent for moderate and severe reflux
Metaclopramide (Regaln®) may provide good relief also improves overall motility
Cisapride (Propulsid®) is no longer marketed due to QTc prolongation
Tegaserod (Zelnorm®) may have some activity

G. Hypocontracting Esophagus [1]

Usually diagnosed as nonspecific motility disorder
Esophageal manometry shows
1. Low amplitude (<30mmHg) contractions OR
2. Failed peristalsis in which wave does not traverse entire length of distal esophagus
Commonly associated with reflux esophagitis
Heartburn and acid regurgitation more common than dysphagia
H2-antagonists or proton pump inhibitors are used
Cisapride was generally effective but is no longer marketed in USA

H. Evaluation

References