CANINE GI MEDICINE

3. • The esophagus is the hollow, muscular tube that passes food and liquid from
your throat to your stomach.
• It functions as part of digestive system.
• Upper Esophageal Sphincter is striated (cricopharyngeus muscles).
• Body has both striated and smooth muscles
• Lower Esophageal Sphincter has smooth muscles.
• Entire canine oesophagus is striated.
• Lower 1/3rd of feline one is smooth.
• Glossopharyngeal, pharyngeal and recurrent laryngeal nerve innervates.

7. • The term megaesophagus describes a syndrome of segmental or
diffuse oesophageal dilatation.
• It is a disorder characterized by diffuse esophageal dilatation and
aperistalsis.
• Mainly classified into:
A.Congenital form
B.Acquired form (Idiopathic and Secondary)

8. • Congenital megaesophagus (born with the condition) is
developmental anomaly and causes regurgitation starting at weaning
when puppies and kittens begin eating solid food.
• Acquired megaesophagus occurs later in life, in young adults and
middle-aged animals.
• When esophageal motility is decreased or absent, food and liquid
accumulate in the esophagus and have difficulty getting into the
stomach.

9. • Damage between the nerves and muscles of the esophagus (e.g.,
myasthenia gravis).
• Degeneration or trauma in the brain or spinal cord.
• A blockage of the esophagus by a foreign body, tumor, or scar tissue
• Severe inflammation of the esophagus.
• Hormonal disease (e.g., hypothyroidism or hypoadrenocorticism, also
known as Addison's Disease).
• Exposure to a toxin (Lead, Thallium, Snake Envenomation).

17. • There are no blood tests specifically for megaesophagus, diagnostic tests
may uncover the underlying cause, if there is one.
• Blood test for myasthenia gravis, a failure of the nerves and muscles to
communicate.
• A complete blood count, serum biochemistry panel that includes creatine
kinase activity and urinalysis should be performed in all regurgitating
patients, especially in cases where MO is suspected.
• In addition, an acetylcholine receptor antibody test should be performed in
all cases of acquired MO, as it is the most commonly identified underlying
disease.
• A baseline cortisol concentration is helpful to rule out Addison’s disease,
which is less likely; measurement of thyroxine/ canine thyroid-stimulating
hormone is indicated in dogs with suspicion of hypothyroidism.

26. • Aspiration pneumonia and esophagitis are the most common
complications.
• Broad spectrum antibiotics for aspiration pneumonia
• Promotility drugs like metoclopramide and cisapride has no action
on canine megaesophagus as they act on only smooth muscles but
bethanechol may be better.