other names: stroke, vascular event, infarct, transient ischemic attack
Overview
Cerebrovascular accidents, often referred to as strokes, occur when the blood supply to part of the brain is suddenly disrupted. These events can cause a sudden onset of neurological symptoms and require prompt recognition and supportive care to optimize outcomes. Strokes are broadly categorized into two main types:
- Ischemic strokes result from an obstruction within a blood vessel that supplies the brain. This blockage can be caused by a blood clot (thrombus) or other embolic material, such as fat, tumor cells, or bacteria.
- Hemorrhagic strokes occur when a blood vessel ruptures, leading to bleeding into the brain. This bleeding can damage brain tissue and increase pressure within the skull.
Causes
There are several potential underlying causes of strokes in dogs and cats. Common risk factors include high blood pressure, heart disease, clotting including kidney disease, Cushing’s disease, hyperthyroidism and hypothyroidism – all of which can alter the body’s ability to maintain normal vascular function. Less commonly, certain types of cancer, systemic infections, and bleeding disorders, can also lead to cerebrovascular accidents
In approximately 50% of cases, no definitive cause is identified. These are classified as idiopathic strokes. It may feel frustrating not to identify an exact cause for the stroke, but the good news is that dogs with idiopathic strokes usually have a lower chance of having another stroke in the future.
Clinical Signs
Clinical signs of a stroke in dogs and cats depend largely on the location and extent of the brain area affected. Most strokes present with a sudden, non-progressive onset of neurological dysfunction, meaning the signs appear abruptly and generally do not worsen over time. Common signs include a head tilt, seizures, blindness, balance issues, or difficulty walking. Despite how alarming these symptoms may appear, it’s important to note that strokes are typically not painful, which can help distinguish them from other acute neurologic conditions.
Diagnosis
Diagnosis of a stroke in dogs and cats relies primarily on advanced imaging. The gold standard for confirming a stroke is MRI, which can identify ischemic and hemorrhagic lesions. It’s important to understand that some strokes can be too small to show up on an MRI. However, when there are no other abnormalities seen and neurological signs appear suddenly, a cerebrovascular accident is still the most likely cause.
If a stroke is confirmed or suspected, additional tests are usually recommended to help identify any underlying causes. These may include:
- Routine blood work and urinalysis
- Blood pressure measurement
- X-rays and abdominal ultrasound to look for underlying cancers
- Endocrine testing for Cushing’s disease and thyroid hormone levels
- Cardiac evaluation to assess for underlying heart disease
- Coagulation testing to evaluate blood clotting function
Treatment
There is no specific cure for stroke in veterinary patients. Supportive care plays a critical role in promoting recovery. Treatment is focused on stabilizing the patient, managing clinical signs, and addressing any underlying conditions or diseases that may have contributed to the stroke.
Key aspects of supportive care include:
- Soft, padded bed and regular repositioning to prevent pressure sores
- Assisted feeding if needed
- Mobility support, particularly in larger dogs, using tools such as slings or harnesses to aid walking and prevent complications
- Monitoring for complications, including aspiration pneumonia, urinary retention, and worsening neurologic signs
Symptomatic treatment is tailored to the patient’s specific clinical signs. This may include:
- Anti-nausea or anti-vertigo medications for balance-related symptoms
- Anticonvulsants if seizures are present
- Blood pressure medications if hypertension is diagnosed
Although thrombolytic therapies are used in human medicine to dissolve clots, they are not regularly used in veterinary medicine due to concerns over safety and limited proven efficacy.
Finally, physical therapy and rehabilitation can significantly improve long-term outcomes by supporting neurologic recovery, improving strength, and maintaining joint and muscle function.
Prognosis
The prognosis for dogs and cats recovering from a stroke is generally favorable, particularly when the stroke is small and located in a non-critical area of the brain. Many patients begin to show signs of improvement within the first few days, and functional recovery often continues over the course of several weeks to months. In some cases, full neurological function may return, while others may be left with mild residual deficits, such as a persistent head tilt or subtle incoordination.
The risk of stroke recurrence is considered low when no identifiable underlying cause is found. However, recurrent strokes are possible, especially if the underlying condition cannot be controlled. For this reason, ongoing monitoring and periodic follow-up testing may be recommended to detect and manage any suspected risk factors.
With appropriate care and management, many pets go on to live happy, comfortable lives following a Cerebrovascular accident.