All Pets Veterinary Clinic
Megaesophagus Secondary to PRAA
Lily is an 8 week old puppy presented for a history of chronic vomiting.
The owners obtained Lily when she was 3 weeks old. As she aged, the owners
tried to wean her to solid food. However, Lily would always regurgitate after
eating. X-rays with and without barium were taken to verify a suspected megaesophagus
and to determine if there was an area of narrowing (stricture).
The x-ray at left is one of the films taken with barium. Barium is a contrast media
that can be used to outline hollow structures since it is bright white on x-rays.
The x-ray at the left shows barium in a widened esophagus and a sudden area of narrowing
and a lesser amount of barium after the stricture. The stricture occurs at the level
of the 5th to 6th rib. In this area, it can be presumed that the stricture is caused
by persistant right aortic arch (PRAA) or vascular ring. A PRAA is a blood vessel that
should have deteriorated during normal development. In rare cases it remains intact
and can encircle the esophagus and prevent the passage of food into the stomach. As
time goes on the esophagus ahead of the vessel will enlarge and overfill with food that
is supposed to go to the stomach. Since the food cannot pass, the affected animal will
Early surgical intervention provides the best chance for long term cure. Medical management
will often be unsuccessful for megaesophagus due to PRAA. Inhalation of regurgitated
food will often end in aspiration pneumonia and can be fatal. Lily's owners consulted
The picture at left shows the isolated PRAA (under the curved tip clamp in the center).
The enlarged portion of the esophagus is towards the left of the opening. The heart is
towards the lower right of the picture. The opened mediastinum (tissues surrounding
the heart and major vessels) is held within the two clamps on the right.
The vessel causing the entrapment (PRAA) was tied with two pieces of suture and cut. The
picture at the left shows one end of the ligated vessel (small white circular tissue
slightly above the lower clamp. The chest cavity was then closed in several layers. Lily
will be fed small amounts of food several times per day for the next several weeks.
With time, the enlarged portion of the esophagus should hopefully decrease in size and
increase in contractility as the lower portion of the esophagus can now accept food. She
will be monitored carefully for surgical complications and failure of the enlarged
portion of the esophagus to regain normal function.
Special thanks to Lily's owners for allowing us to
share this case.
Karen Blakeley, DVM, MPH
30 May 2004