Hydrocephalus in dogs is a neurological condition where cerebrospinal fluid (CSF) abnormally accumulates and expands in the brain's ventricles, increasing pressure on brain tissue. This condition, commonly called "water on the brain," can lead to serious neurological problems if untreated. Hydrocephalus may be congenital or acquired later in life, with toy and miniature breeds like Yorkshire Terriers, Maltese, and Chihuahuas being especially predisposed in congenital cases.
The accumulation of CSF results from either increased production, decreased absorption, or blockage of fluid pathways in the brain. Primary hydrocephalus is congenital and present at birth, often due to developmental anomalies in the brain or skull. In contrast, secondary hydrocephalus develops later and is typically associated with tumours, inflammation, abscesses, or trauma affecting CSF circulation.
Various factors can cause congenital hydrocephalus in puppies, such as prenatal infections in the mother, administration of certain medications that may cause birth defects, or trauma during difficult births, leading to pressure damage in growing brains.
Symptoms usually appear between 8 to 12 weeks old in puppies with congenital hydrocephalus. Because their skull bones haven't fully fused, fluid accumulation leads to an enlarged, dome-shaped head often with soft spots (fontanelles). Common signs include seizures, head pressing, abnormal downward and outward eye gaze (ventrolateral strabismus), behavioural changes, blindness, and abnormal gait.
Puppies affected are often the "runts" of their litter, slower to learn and more challenging to house-train. Some dogs may show acute symptoms, while others experience gradual worsening over time.
A vet typically suspects hydrocephalus based on clinical signs and medical history. Thorough physical and neurological examinations are vital, followed by imaging like CT scans or MRI to confirm fluid buildup and assess severity. These scans help rule out other neurological conditions and provide a clear diagnosis.
Small and toy breeds show a higher tendency for hydrocephalus, including:
Treatment depends on severity. Mild cases may respond to medication aimed at reducing CSF production and controlling seizures, such as corticosteroids and diuretics. These treatments help manage symptoms but often provide only temporary relief.
More severe cases might require surgical intervention via placement of a ventriculoperitoneal shunt to drain excess fluid safely from the brain to the abdomen. This surgery is specialised, costly, and requires a skilled veterinary neurologist. Unfortunately, not all dogs qualify for or can afford this surgery, and risks exist.
For severely affected dogs where treatment is unlikely to improve quality of life, humane euthanasia is sometimes the kindest option, and a vet will advise accordingly.
Hydrocephalus is best prevented by responsible breeding practices. Dogs diagnosed with or from litters affected by hydrocephalus should not be bred. Maintaining careful records of breeding lines and health histories is essential to reduce the occurrence of this condition.
Prospective owners should seek reputable breeders who perform health checks and genetic screenings to avoid producing puppies with congenital defects like hydrocephalus.
Hydrocephalus in dogs is a challenging condition requiring early recognition and veterinary intervention to manage symptoms and support quality of life. While not all cases have a positive outcome, advances in diagnosis and treatment offer hope for affected pets. Responsible breeding and informed care remain the best prevention strategies.