You Make The Diagnosis: Chihuahua Congenital Defects

During their first examination, I check puppies for congenital defects.  What is the most common congenital defect observed in Chihuahuas?  Will it correct over time?  Is it associated with any other medical problems? 


Answer:  Open Fontanelle (Soft Spot)

Open fontanelle’s occur when the bones of the skull fail to meet and fuse.  I usually find them on the pup’s forehead.  Most will close with time and are considered normal for the breed.  If the soft spot is large, I worry about the puppy developing hydrocephalus.  Hydrocephalus, which loosely translated means ‘water brain’ is an excessive accumulation of fluid within the skull.  Pressure from the fluid interferes with normal brain function and may cause severe neurologic disease.  If your puppy has a soft spot, be careful.  Since there is no bone to protect the brain, trauma to this area may cause serious neurological problems.

Unfortunately, open fontanelles are often consider acceptable to some breeders.  The beautiful puppy in the photo did not suffer from this condition.  I posted Bella’s picture because she is one of the healthiest and most well behaved Chihuahua’s I have ever had the privilege to examine.     

In addition to open fontanelles, I also check for several other congenital defects including cleft palates, umbilical hernias, heart murmurs and anal defects.  A common problem in all toy breeds is medial patella luxations.  In this condition, the pup’s knee cap rests out of the joint, on the inner side of the knee.  These pups often require surgical repair when they are older. 

For more information on congenital defects in other breeds of dogs, please see my upcoming post titled “Congenital Defects In Puppies”.

Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.