Cerebral Edema in Cats

Cerebral edema is an accumulation of fluid in the brain that results in swelling. The fluid accumulating in the brain and surrounding tissues creates intracranial pressure that affects brain function and causes neurological symptoms. A cat with cerebral edema will show signs of distress and altered consciousness that will be apparent in its behavior and nervous functions, such as coordination and vision. In cats, cerebral edema is often the result of physical trauma but may be related to several other conditions such as feline diabetes or a reaction to a toxin the animal has been exposed to. The condition is very serious and life-threatening; it requires immediate veterinary treatment. 

Cerebral edema results in impaired brain function and neurological symptoms that can range from moderate to severe. Symptoms include:

• Listlessness/weakness
• Behavioral/personality changes
• Loss of consciousness or coma
• Seizures
• Blindness/visual disturbances
• Fever
• Paralysis or head listing to one side
• Lack of coordination, staggering
• Pupil dilation or constriction
• Lack of responsiveness to stimulation

There can be various reasons for fluid build-up in a cat’s brain, these include:

• Trauma or injury to the head
• Trauma or injury to a related part of the nervous system e.g. spinal injury
• Viral infection
• Bacterial infection
• Fungal or parasitic infection
• Poisoning/toxicity
• Diabetes
• Brain tumor 

Your veterinarian will first do a neurological exam to evaluate brain function. This will involve checking for level of consciousness, coordination, reaction to stimulation and neurological functioning, such as vision. As a pet owner, you should be prepared to provide a detailed history including your pet’s recent activities, exposures, and diet that may help your veterinarian determine the cause and duration of the edema. 

Laboratory tests that may be ordered to confirm cerebral edema and identify possible causes include electroencephalogram (EEG), MRI, CT scan, and X-rays. These tests will help show the extent of the edema as well as reveal causes such as a brain trauma or tumor. Your veterinarian will also most likely order blood work and urinalysis to assist in determining the underlying cause of the edema. These tests will help determine or rule out diseases and conditions such as diabetes, toxins or infections. In some cases, your veterinarian may take a sample of cerebrospinal fluid or brain tissue when infection of the nervous system is suspected.

Your veterinarian will treat the cause of cerebral edemas and hospitalize your cat to monitor its condition. Drug and surgical intervention may also be required depending on the severity of the edema. Relapse of cerebral edema is possible and the cat should be closely monitored during and after treatment for progression of the cerebral edema and signs of relapse.

Causal Treatment

Treatment of cerebral edema in cats will largely focus on identifying the underlying cause of the edema and providing appropriate treatment for that condition. Examples of such treatment are antibiotic for a bacterial infection or appropriate medication to counteract toxicity.

Monitoring and Care

Cerebral edema is a serious, life-threatening condition that will require veterinary hospitalization to monitor your cat’s condition and provide medical support as needed. Your pet’s vital signs such as temperature and oxygen levels will be monitored and oxygen therapy or medication to control fever administered. In addition, dehydration or overhydration will exacerbate the condition and will be closely monitored and treated with intravenous fluids as required.

Drug Intervention

Medication that may be prescribed and administered by your vet to counteract the cerebral swelling includes mannitol or frusemide. In some cases, steroids are used to decrease inflammation.  This method is not as commonly used, as steroids are not as effective for brain injury as for spinal injury and can produce unwanted side-effects.

Your veterinarian may also prescribe sedatives for an agitated animal or anticonvulsants if seizures are present. 

Surgical

Surgical intervention may be necessary to provide drainage and relieve cerebral pressure or remove brain tumors if present.

After hospitalization for cerebral edema, the pet owner should ensure that their cat is provided with a safe, quiet environment, free of physical hazards and stimulation such as loud sounds, bright lights and disturbance from other pets.

The prognosis of your pet depends on the cause, severity and the duration of the edema. It may take your cat several weeks or months to recover. The pet owner should continue treatment as prescribed by their veterinarian and monitor fluid and food intake and output. Special attention should be given to any changes in temperature or neurological condition. Seek veterinary help immediately if there is sign of a relapse.

For an animal that is agitated or unable to rest, sedatives may be prescribed by your veterinarian to assist in your cat’s recovery. In cases that residual brain damage exists or is suspected, physiotherapy may be recommended.