LearningRadiology - Achalasia

Achalasia

• Cause is generally considered a defect in the cholinergic receptors of Auerbach’s plexus (between the inner circular and the outer longitudinal muscle layers of the muscularis).

• Characteristically, primary peristaltic stripping waves are absent in either the upper (early) or the whole (late) esophagus. Tertiary waves may be present but in the late stages the esophagus is atonic. The lower esophageal sphincter fails to relax.

• There is a positive response (forceful contraction) following an injection of methacholine but this is not pathognomonic. This contraction may be associated with severe substernal pain.

• The stomach bubble is usually present in early stages, absent in the later stages of the disease. Hurst phenomenon=transit of food through EG junction 2° increased hydrostatic pressure of barium column

• In the late stages, the distal esophagus tends to make a right angle bend before entering the stomach due to the extreme tortuosity of the esophagus. This is called “bird’s beak” or “rat-tail” sign.

• Chagas disease (trypanasoma cruzi) is indistinguishable from achalasia and is the result of destruction of the ganglion cells.

• Carcinoma of the esophagus can complicate achalasia in 7% of cases, usually in mid-esophagus.

DDX:

• Reflux esophagitis and stricture

—narrowing is higher than EG junction

—peristalsis may be preserved

• Carcinoma

—usually less dilated

—peristalsis preserved

• Scleroderma

—empties on standing

• Chagas disease

—indistinguishable by x-ray

WH/92