Radiographic Diagnosis of Anal Atresia with Severe Megacolon in a Three-Month-Old Female Puppy: A Case Report

Background: Anal atresia is a congenital anomaly in dogs characterized by the dysdevelopment of the anal orifice, leading to distal gastrointestinal obstruction. This condition requires early diagnosis and surgical intervention to prevent life-threatening complications such as severe megacolon and sepsis. While clinical signs typically manifest shortly after birth, this patient presented an unusual survival period of three months without surgical intervention, which was attributed to specific dietary factors. Methods: A three-month-old intact female mixed-breed puppy with a history of progressive abdominal distension and constipation since birth was referred. Physical examination revealed a severely distended but nonpainful abdomen and complete absence of a patent anal opening. Notably, the puppy had been exclusively fed a milk-based diet during this period. Survey abdominal radiography including dorsoventral, ventrodorsal, and lateral projections was performed as the primary diagnostic modality. Results: Radiographic evaluation revealed severe generalized megacolon with massive colonic dilation exceeding three times the diameter of the seventh lumbar vertebra. The colon showed abrupt termination in the pelvic canal, with a complete absence of gas or fecal material in the distal rectal lumen, the pathognomonic radiographic sign confirming anal atresia. The exclusive milk diet during the three-month period likely contributed to reduced fecal impaction and slower disease progression, explaining the prolonged survival without surgical intervention. Conclusion: This case highlights that survey radiography provides a rapid, accurate, and cost-effective method for the definitive diagnosis of anal atresia. The pathognomonic findings of severe megacolon coupled with the absence of rectal gas enable immediate diagnosis and facilitate urgent surgical planning. Furthermore, this report highlights how dietary factors, specifically exclusive milk feeding, can modify disease progression in congenital gastrointestinal obstructions, providing valuable insights for the clinical management of similar cases.

کلیدواژه ها:

Radiography ، Puppy ، Megacolon ، Anal atresia ، Congenital anomaly