What Is Caudal Occipital Malformation in Dogs?
Caudal occipital malformation in dogs, also known as Chiari-like malformation, is a congenital neurological condition. It involves compression of the brain and obstruction of cerebrospinal fluid (CSF) flow, leading to various neurological symptoms.
Predisposed Breeds
Small breeds are most commonly affected, including:
- Cavalier King Charles Spaniel
- Brussels Griffon
- Maltese
- Chihuahua
- Yorkshire Terrier
Symptoms typically appear between 5 months and adulthood. There is no known predisposition related to sex or color.
Symptoms
Common clinical signs include:
- Neck pain, worsened by touch, excitement, or wearing a collar
- Scratching of the neck, ears, or face
- Unsteady gait
- Seizures (though a direct link to the malformation is not established)
- Deafness, especially in Cavalier King Charles Spaniels
Diagnosis
Magnetic resonance imaging (MRI) is the preferred diagnostic tool. It allows visualization of cerebellar and brainstem displacement through the foramen magnum and detection of any syringomyelia.
Treatment
Treatment primarily aims to alleviate pain. Options include:
- Medications: diuretics, antacids, non-steroidal anti-inflammatory drugs, neurogenic analgesics, steroids
- Surgery: decompression of the foramen magnum to restore CSF flow
It’s important to note that surgery does not guarantee complete recovery, and approximately 50% of dogs may experience deterioration after two to three years.
Prognosis
The prognosis for dogs with caudal occipital malformation varies significantly. Some dogs remain stable for years, while others may experience rapid deterioration. Surgical intervention can improve symptoms in about 80% of cases, but recurrence due to scar tissue formation occurs in approximately 25% of dogs. Regular veterinary follow-up, including periodic blood tests, is essential to adjust treatments and monitor the dog’s overall health.
