Atresia ani (“imperforate anus”) is a congenital birth defect where the anus is missing, closed, too narrow, or the rectum doesn’t connect normally.

 

It is usually discovered in newborns or very young puppies/kittens, often when they begin to strain, develop belly swelling, or fail to pass stool normally.

 

Surgery is the definitive treatment.

 

The goal is to:

 

• create or open a functional anal opening,

• connect the rectum to the anus when needed,

• protect continence (control) as much as possible,

• prevent complications like megacolon, infection, or failure to thrive.

 

Early surgery is emphasised in veterinary literature to reduce risks such as poor body condition, irreversible colon enlargement (megacolon), and urinary infections.