"Bird beak" appearance on barium swallow study is seen in:

Barium study feature of few esophageal diseases Diffuse esophageal spasm: "Yo-Yo" motion of barium "Corkscrew" appearance (scalloped configuration of barium column) "Rosary-bead/Shish kebab" configuration (compamentalization of barium column) Feline esophagus: Gastroesophageal reflux disease Double-barrel esophagus: Mallory-Weiss tear Intramural abscess Intraluminal diveiculum Achalasia cardia: "Bird beak" deformity Absence of primary peristalsis below level of cricopharyngeus Candidal esophagitis: Cobble stone mucosa Cytomegalovirus esophagitis: Giant ovoid flat ulcers (vasculitis of submucosal vessels) Herpes esophagitis: Discrete superficial punctate/linear serpentine/stellate/diamond shaped ulcers Hiatus hernia: Epiphrenic bulge > 4 longitudinal coarse thick gastric folds above gastroesophageal junction or in the suprahiatal pouch Distance between B ring and hiatal margin > 2 cm Scleroderma: Esophageal shoening Sliding hiatus hernia Carcinoma oesophagus: Rat-tail esophagus Shouldering sign