Pontine Stroke: What It Is and Outlook

A pontine stroke occurs in the pons region of the brainstem—a small part of the brainstem responsible for breathing, heart rate, and blood pressure, among other essential, automatic functions.

Pontine strokes happen when the blood supply to the pons region of the brainstem is cut off. They can be ischemic strokes, which occur when a blood clot blocks flow, or hemorrhagic strokes, which occur when a blood vessel bursts.

Regardless of the stroke type, since the brainstem is involved in several essential functions, recovery is often challenging and depends on the severity of the stroke.

Function of the Pons

The pons is part of the brainstem. It is located above the medulla oblongata and below the cerebral cortex, making it the second-lowest region of the brain. The pons is part of the region that sends messages to the spinal cord and it connects the cerebral cortex and medulla oblongata.

The pons is responsible for many autonomic nervous system functions. These are things that your body does automatically, like regulating your heart rate, responding to pain, and managing your sleep-wake cycle. 

Additionally, the pons is made up of nerves and nerve pathways that send messages between different parts of the brain. It is responsible for maintaining several essential functions in the body, including:

• Movement
• Sensory input, such as hearing and taste
• Balance in the head, neck, and body
• Eye movement
• Sleeping
• Dreaming
• Digestion
• Swallowing
• Breathing
• Heartbeat
  

Types of Pontine Strokes

A pons or pontine stroke occurs when blood flow to the pons region of the brain stem is interrupted. There are two types of pons strokes:

• An ischemic stroke occurs when an artery to the brain becomes blocked by a blood clot. 
• A hemorrhagic stroke occurs when an artery to the brain stem bursts and causes bleeding in the brain.

Pontine strokes are a type of posterior circulation stroke. They are the most common brainstem stroke and makeup around 7% of all ischemic strokes.

Approximately 691,650 individuals have an ischemic stroke each year, with about 48,415 of those individuals experiencing an ischemic pontine stroke.

Hemorrhagic strokes are a less common stroke type and represent approximately 13% of all strokes. A hemorrhagic pontine stroke is uncommon.

Presentation

The way the stroke presents itself depends on which blood vessel is blocked. For example, a clot in the anterior inferior cerebellar artery may cause ipsilateral (on the same side of the body as the clot) stroke symptoms such as one-sided facial weakness, clumsiness, and pain.

In contrast, a clot at the branches of the basilar artery is more likely to produce bilateral symptoms and impaired consciousness.

Several other blood vessels may be involved in a pontine stroke, which may affect one side of the pons, the upper or lower pons, the middle of the pons, or a wider area. While general stroke symptoms may occur, specific symptoms may help point to a brainstem stroke and which blood vessel is affected.

In a hemorrhagic stroke, the main challenge is bleeding into the brain and the increased pressure associated with the bleeding. The size of the hemorrhage and the level of consciousness of the individual are the two main factors associated with presenting symptoms and mortality.

Symptoms

Some early signs or symptoms of a brainstem or pons stroke include:

• Balance issues
• Difficulty swallowing
• Dizziness
• Double vision
• Loss of sensation and coordination
• Nausea
• Numbness
• Slurred speech
• Vertigo, or a spinning sensation
• Weakness in one half of the body
• Decreased consciousness

It is also possible to experience prodromal symptoms before a stroke. Prodromal symptoms are like a warning and may include headache, vertigo, or nausea.

Additionally, while it is uncommon, crescendo transient ischemic attacks (TIAs) called "pontine warning syndrome" are possible. This is where an individual experiences episodes of stroke-like symptoms that only last for a brief period before resolving. They can eventually lead to a stroke. If you believe you're experiencing a TIA, it is essential to seek medical care.

Diagnosis

To diagnose a pontine stroke, a provider can do a neurologic exam and imaging tests of the brain:

• Brain magnetic resonance imaging (MRI) is a test that uses a magnetic field and radio waves to create images of the brain.
• Brain magnetic resonance angiography (MRA) is a test that creates images of the arteries in the brain.
• Computerized tomography (CT) angiogram is a test that uses multiple X-ray images to look for blockages in the arteries.
  

Treatment

A stroke is an emergency that needs immediate medical attention. 

A clot-dissolving drug called tissue plasminogen activator (tPA) can be an effective treatment for ischemic stroke. However, it needs to be given within four-and-a-half hours of the onset of stroke symptoms to work. 

Treating a hemorrhagic stroke sometimes can be done with medication and surgery. 

Survival Rates and Outcomes

Survival rates depend on the type of pontine stroke (ischemic or hemorrhagic) and where the stroke occurred.

In hemorrhagic pontine strokes, the 30-day mortality rate is approximately 48.1%. This number is based on a 2018 systematic review that examined mortality data across several studies. The level of consciousness at admission and hemorrhage size were the most consistent predictors of mortality. Larger hemorrhages have a worse prognosis.

Mortality rates for ischemic strokes are more variable and depend on the location of the stroke. In one 2023 study, the 90-day mortality rate for an ischemic pons stroke was 12%. Of those who survived, 15 experienced disability, which represented 40% of the cohort.

Patients who have experienced a pontine stroke may also be at risk for an additional stroke. In a 2022 study, 13.1% of patients experienced another pontine stroke within a year of the initial stroke.

Recovery

Depending on the extent of the stroke, a pontine stroke may cause several long-term effects. Some long-term effects include loss of sensation or motor control and difficulties with speech or swallowing. 

In severe cases, a person who has had a pontine stroke might need help breathing.

Many patients can make a full recovery from a pontine stroke, though others may have permanent problems with motor function.

In rare cases, a pontine stroke can cause a condition called locked-in syndrome. People with locked-in syndrome are awake, alert, and able to think and understand, but they can only move their eyes.

Recovery from a stroke depends on several factors, including:

• Type and severity of the stroke
• How quickly initial treatment was provided
• Type and intensity of the therapy
• Age
• Prior medical conditions

While some people may only need three to six months to recover after a mild stroke, significant, large strokes may take years to regain lost functions.

Treatments that can help patients recover from a stroke include several therapies, such as:

• Sensory reeducation
• Physical therapy
• Speech therapy
• Occupational therapy
• Mental health therapy

Treatment will also likely focus on treating underlying causes, such as managing diabetes and controlling blood pressure. Good nutrition is also essential.

Sensory Reeducation

People who have a loss of sensation after a stroke may benefit from sensory reeducation. 

This type of therapy uses touch to stimulate sensory processing in the brain. The goal is to retrain the brain by exposing it to different types of sensory input.

Some exercises used in this type of therapy include:

• Touching things with different textures and sizes
• Identifying objects based on how they feel
• Using your hands to find objects hidden inside a bowl of rice or a similar substance

Although this type of therapy is still new, small studies have shown it can be effective at helping people recover sensation after a stroke.

Physical Therapy

Most people recovering from a stroke will need physical therapy.

The goal of treatment is to relearn the simple motor functions needed for daily living, such as standing, walking, sitting, and lying down.

Physical therapy for stroke recovery usually starts with basic movements, such as switching from a prone position to a sitting position. 

As you progress with your physical therapy treatment, you will do exercises that help improve your balance and coordination.

Speech Therapy

A speech therapist can help you recover your ability to speak clearly after a stroke. 

This treatment involves retraining your brain with consistent practice. Speech therapy may also include exercises that help improve your control over your mouth and tongue muscles. 

Occupational Therapy

Occupational therapy is similar to physical therapy and involves relearning motor functions. The goal of occupational therapy is to help you become independent again after a stroke.

Your occupational therapist will help you get back activities of daily skills like eating and drinking, dressing, and bathing. Eventually, you will work on more complex tasks like cooking and doing laundry. 

Mental Health

Both the damage from the stroke and the stress of the stroke can impact an individual's behavior and emotional state. Individuals who have experienced a pontine stroke may benefit from mental health services and support groups.

Prevention

Several factors put you at a higher risk of having a stroke. While some things (like your genes) you do not have control over, many risk factors are modifiable.

Modifiable risk factors include:

• Diabetes
• Drug use
• High blood pressure
• Obesity
• Sedentary lifestyle
• Smoking
• Cholesterol management
• Heart conditions (e.g., atrial fibrillation)

While some conditions, such as diabetes, heart disease, obesity, or elevated blood pressure may be chronic and long-term, adhering to a treatment plan and managing the condition can help to reduce the risk of a stroke.

For example, if you have diabetes, you are two times more likely to have a stroke than people who do not have the condition. However, proper management can help reduce the risk of stroke in those with diabetes.

Non-modifiable risk factors:

• Aging
• Genetics and family history

Addressing risk factors that you have some control over can help lower your risk of having a pontine stroke.

Additionally, other ways to lower your risk of a stroke include:

• Eating a nutritious and balanced diet
• Getting regular exercise
• Limiting alcohol intake
• Managing stress
  

Summary

A stroke in the pons region of the brain can cause serious symptoms like problems with balance and coordination, double vision, loss of sensation, and weakness in half the body. Pons strokes can lead to brain damage. 

This type of stroke is diagnosed with a neurologic examination and imaging tests. Some can be treated with a clot-dissolving medication if given soon enough after symptoms begin.

Individuals who have certain medical conditions, do not get regular exercise, and smoke or use drugs are at higher risk for any kind of stroke. The risk of stroke also increases with age. 

If you have had a stroke, there are treatments that can help you recover and regain your independence, like physical therapy, but it can take time.