In which of the following conditions, uniform dilation of esophagus is seen -a)  Sclerodermab)  Achalasia cardiac) Dermatomyositisd) Trypanosoma cruzi infection
Achalasia cardia

Achalasia cardia is a motor disorder of the esophageal smooth muscle, characterized by -
	1. Aperistalsis
	2. Failure of relaxion of the LES with swallowing
	3. Increased resting tone of LES

Pathogenesis
It is due to dysfunction of inhibitory neurons containing nitric oxide and vasoactive intestinal polypeptide in the distal intestine. The cholinergic innervation of the LES is intact or affected only in the advanced stage.
There is neurogenic degeneration either idiopathic or due to infection. The degenerative changes are either intrinsic (degeneration of ganglion cells of Aurebach's myentric plexus) or extrinsic (extra esophageal vagus nerve or the dorsal motor nucleus of vagus).
As a result of the abnormality, LES fails to relax and there is progressive dilatation of esophagus above the level of ​LES.

Clinical findings

Both sexes are equally affected (Ref : Maingot's 10th/e p. 846)
May develop at any age but peak years are from 30 to 60.
Classical clinical symptom is progressive dysphagia for both solids and liquids. Dysphagia is worsened by emotional stress and hurried eating.
Regurgitation and pulmonary aspiration occur because of retention of large volumes of saliva and ingested food in the esophagus.
Esophagitis with ulceration may occur with chronic retention of food.
Pain is infrequent in classical achlasia but a variant called vigrous achlasia is characterized by chest pain and esophageal spasms that generate non-propulsive high-pressure waves in the body of the esophagus.

Secondry achalasia may arise in chagas disease, in which trypanosoma cruzi causes destruction of myentric plexus of the esophagus, duodenum, colon, and ureter, with resultant dilatation of these viscera.
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