What is hydrocephalus in dogs and cats, and how does it present?

Hydrocephalus is an accumulation of cerebrospinal fluid in the brain that causes ventricular enlargement. Clinical signs include seizures, unsteady gait, deteriorating vision, and changes in behaviour. If obvious symptoms appear, please consult your vet.

How does a vet diagnose hydrocephalus?

Diagnosis relies mainly on neurological examination and imaging. MRI provides the most detailed view; CT and blood tests are also commonly used to rule out other causes.

Can hydrocephalus be treated or managed?

Treatment depends on the underlying cause and severity. Options may include medical management or surgical decompression. A specialist should assess your pet and develop a long-term monitoring plan.

What should I bring to the appointment?

Bring the time of onset, a description of how symptoms have progressed, video of any seizures or walking abnormalities, a record of diet and toileting from the past week, and a current medication list to help your vet assess quickly.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Hydrocephalus in Dogs & Cats: Seizures, Gait Problems, Imaging & Treatment [2025]

Hydrocephalus is an abnormal accumulation of cerebrospinal fluid in the brain's ventricles, most common in small and brachycephalic breeds. The congenital form often appears in young animals; mild cases can be managed medically, while severe cases may require shunt surgery.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: AVMA, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate emergency care

•Continuous seizures lasting more than a few minutes that cannot be stopped
•Prolonged loss of consciousness with no response
•Rapid breathing or significantly worsening difficulty swallowing

Schedule a clinic visit soon (within 24–72 hours)

•Intermittent seizures or minor twitching with brief recovery intervals
•Unsteady gait, frequent falling, or circling behavior
•Vision deterioration or noticeably reduced response to light

01What Symptoms Signal a Problem?

Hydrocephalus can produce a range of neurological signs that may develop gradually or appear suddenly. A veterinarian should evaluate the underlying cause and assess intracranial pressure.

Intermittent or continuous seizures, ranging from focal to generalised
Unsteady gait, frequent stumbling, or circling behaviour
Deteriorating vision or reduced response to light — bumping into objects
Mental dullness, increased lethargy, or brief episodes of unconsciousness

Seek emergency care immediately if you notice the following symptoms:

⚠️ Continuous seizure lasting several minutes that does not stop on its own
⚠️ Prolonged loss of consciousness with no response to stimulation
⚠️ Noticeably worsening rapid breathing or difficulty swallowing

02How to Monitor at Home and Decide When to See a Vet

Observing and recording behavioural and physical changes at home helps your veterinarian assess severity and track disease progression.

Note whether your pet is alert, and track any changes in responsiveness or activity level
Record daily appetite and actual food intake — any increases or decreases
Watch for changes in urination and defecation, such as incontinence or constipation
Measure and log daily water intake for any abnormal increases or decreases
Weigh your pet weekly and track the trend over time
If seizures or gait abnormalities occur, record a short video on your phone to bring to the appointment

03How Will the Vet Make a Diagnosis? Common Tests Explained

At the clinic, neurological assessment is the foundation, supported by bloodwork and imaging to confirm ventricular changes, assess intracranial pressure, and rule out other causes.

A thorough physical and neurological examination to assess reflexes and any localising deficits

Blood and biochemistry panel to evaluate internal medicine factors and infection markers

Radiographs (X-rays) as a preliminary assessment to check skull and structural changes

CT (computed tomography) to evaluate ventricular enlargement and structural abnormalities

MRI (magnetic resonance imaging) for the most detailed soft-tissue brain images

Referral to a specialist hospital or veterinary centre with MRI capability is recommended

04Treatment and Care After Diagnosis: Medications, Diet & Home Management

Treatment may include medical management, surgical decompression, and long-term follow-up. The treatment plan must be evaluated and regularly adjusted by a specialist.

Initial management focuses on medication to control symptoms and reduce intracranial pressure, with ongoing monitoring by your vet
Surgical decompression (e.g. shunt placement) is considered based on disease severity and specialist assessment
Corticosteroid or other drug use must be followed under veterinary guidance to monitor for side effects
Regular recheck appointments to track neurological function and repeat imaging for comparison
Dietary and fluid management adjusted to the pet's condition to support overall control
A neurology or specialist referral is recommended for long-term management

05What to Prepare Before the Appointment: Key Information to Help Your Vet

Note the date of the first episode and create a timeline of how symptoms have changed

Record video of any seizures, abnormal walking, or balance problems for the vet to review

List all current prescription medications, supplements, and any known allergies

Bring a record of diet, water intake, and toileting from the past week

Bring any previous imaging or diagnostic reports (if available) for comparison

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Incoordination

Vision loss

Walking in circles

Unconsciousness

Involuntary eye movement

Seizure

Convulsion