Brainstem Stroke (Stroke)

What is Brainstem Stroke (Stroke)?

Brainstem stroke is a serious and life-threatening kind of stroke. There are two main types: hemorrhagic and ischemic. The former involves bleeding in the brain, while the latter involves a lack of blood flow to the brain. These kinds of strokes are a major cause of death and disability worldwide. The ischemic type of brainstem stroke tends to occur more commonly than the hemorrhagic type. Recognizing the symptoms early and getting prompt treatment can improve the chances of recovery.

The brainstem sits at the back of the brain and connects the main part of the brain with the spinal cord. It’s made up of three parts: the midbrain, the pons, and the medulla oblongata. The brainstem has many important jobs, including regulating our breathing, heart rate, and blood pressure. It also plays a role in maintaining our consciousness and controlling our sleep-wake cycles. Furthermore, the brainstem contains clusters of nerve cells that help control our sense of vision, balance, hearing, swallowing, taste, speech, and movements, and sensations in the face.

The blood supply to the brainstem comes from several different arteries, supplying different parts, including the medulla oblongata, pons, and midbrain. The functions of these different parts mean that an interruption to their blood supply can have serious consequences.

A brainstem infarction is when some of the tissue in the brainstem dies because it isn’t getting enough oxygen. Recognizing the structure, blood supply, and the results of a physical exam can help medical professionals make a fast diagnosis and provide life-saving treatment. Time is critical in managing this condition. Early treatment can significantly reduce the risk of death and disability.

The brainstem is involved in about one-third of all ischemic strokes and has a significant impact globally in terms of death and disability. The pons are the part most often affected. Strokes in the medulla oblongata make up about 7 percent of all ischemic brainstem strokes, mostly affecting the lateral subtypes, and they are more common in men than women (a ratio of 3 to 1).

Two common causes of strokes in the brainstem are atherosclerosis (a buildup of fatty deposits in the arteries) and dissections in the vertebral arteries (tears in the artery walls). Strokes in the pons can either occur alone or as part of a larger stroke affecting the back part of the brain. There are several different types of pontine strokes, with the most common caused by atherosclerosis of the small arteries in the brain or a blockage in the basilar artery.

Isolated strokes in the midbrain are rare but can occur together with strokes in the cerebellum, pons, or thalamus. Hemorrhagic strokes frequently occur in the dorsal part of the pons, the part that faces the back of the head.

What Causes Brainstem Stroke (Stroke)?

Ischemic brainstem strokes, or brainstem infarctions, occur when blood flow to any part of the brainstem is interrupted or when there’s bleeding. This can be caused by issues like blockages or narrowings in the blood vessels that supply the brainstem. Common causes of these interruptions include atherosclerosis (a build-up of fatty deposits on the inside of arteries), blood clots, the break-down of fatty substances, tumors, arterial dissections (tears in the wall of an artery), and trauma.

A closer look at specific forms of brainstem strokes, medulla oblongata infarcts, shows that most are caused by narrowed arteries in the vertebral area. Arterial dissections are the cause in about a quarter of cases, while clots originating from the heart account for the rest.

Atherosclerotic disease of large vessels is the leading cause of all ischemic strokes, regardless of where in the brain they happen. In infarcts affecting the midbrain region, clots from the heart are common. In contrast, dissections are common in strokes impacting the medulla area.

About 25% of ischemic strokes happen in the back of the brain, with 60% affecting the brainstem and 40% the cerebellum. In terms of the causes of these strokes, atherothrombosis – a condition where hardened arteries lead to blood clot formation – is the most common cause in all arterial territories. Clots from the heart account for 15% to 30% of these strokes.

Certain risk factors increase the likelihood of all types of stroke, such as high blood pressure, diabetes, metabolic diseases, high cholesterol, smoking, obesity, history of heart disease, irregular heartbeat, sleep apnea, sedentary lifestyle, use of oral contraceptives, certain types of arterial disease, trauma, and spinal manipulation. The risk factors for ischemic brainstem stroke include atherosclerosis, high blood pressure, diabetes, smoking, atrial fibrillation, high cholesterol, heart disease, embolism, and artery dissections.

On the other hand, hemorrhagic brainstem strokes are caused by conditions such as high blood pressure, which accounts for nearly all cases, blood-thinning therapy, certain types of blood vessel abnormalities, and amyloid angiopathy, which is a condition that causes blood vessels in the brain to become weak and potentially rupture.

Risk Factors and Frequency for Brainstem Stroke (Stroke)

Globally, health conditions tied to lifestyle choices, such as heart disease, stroke, and diabetes, are on the rise, affecting both developed and developing countries. One way to understand the impact of strokes is to consider the number of disease-adjusted life years, which is at 122 million globally. In the U.S., someone suffers a stroke every 40 seconds. Research shows that 10% to 15% of all strokes happen in the brainstem.

The risk of stroke for adults aged 25 and older varies, with men having a 23.3% to 26.0% chance and women a 23.7% to 26.5% chance. The likelihood also differs from one region to another. Eastern sub-Saharan Africa has the lowest risk at 11.8%, while East Asia has the highest at 38.8%. Of all nations, China has the highest estimated life-time risk of stroke at 39.3%.

The most common area affected by brainstem strokes is the pons, accounting for 60% of such cases. Vertebral artery strokes make up 23% of cases, while brainstem strokes make up 11% of all ischemic strokes. Strokes can also affect other regions like the cerebellar and the posterior cerebral artery territory.

• About 27% of cases affect the pons.
• 14% involve the medulla.
• The midbrain is affected in 7% of cases.
• The cerebellar is implicated in 7% of strokes.
• Posterior cerebral artery territory is involved in 36% of cases.
• Multiple sites can be affected concurrently in 9% of cases.
• Pure pons strokes were found in 3% of all ischemic strokes.

It’s more likely for strokes to occur in the lateral part of the medulla than the medial part. Similarly, it’s rare for the midbrain to be affected. Wallenberg’s syndrome, or posterior cerebellar artery syndrome, is the most usual form of brainstem stroke. The second most frequent is the anterior inferior cerebellar artery syndrome, or lateral pontine syndrome.

Only a small percentage (10%) of all brain hemorrhages occur in the brainstem, affecting 2 to 4 in every 100,000 people each year. This kind of stroke most often affects the pons (60% to 80% of brainstem strokes) and is more frequent in men and people aged 40 to 60. Women who have brainstem strokes, however, have a higher survival rate.

Signs and Symptoms of Brainstem Stroke (Stroke)

A stroke occurs when blood flow to a part of the brain is cut off, and it can result in the loss of nearly 1.9 million brain cells every minute it goes untreated. Patients experiencing a stroke may have trouble breathing or communicating, suffer from mental confusion, or even have physical injuries like trauma. They may also have altered respiratory drive, meaning their body doesn’t tell them to breathe as it should, or issues with vomiting or mechanical airway obstruction. That’s why it’s crucial to promptly assess the situation and intervene as soon as possible.

Determining the exact time when the symptoms first started is a key part of treating a stroke. This information can be provided by the patient themselves or by others who were present when symptoms started. Other crucial information includes the patient’s current medication, especially if they are on medications for conditions like diabetes, epilepsy, mental disorders, or blood thinners. The doctor also needs to know about any existing medical conditions and risks the patient might have. If the patient is showing signs of a hemorrhagic stroke, which involves bleeding in the brain, an immediate CT scan is essential. Symptoms of hemorrhagic stroke can include uncontrolled high blood pressure, a sudden headache, vomiting, and signs of increased pressure inside the skull.

Brainstem strokes can lead to a variety of symptoms depending on which part of the brainstem is affected. Here is an outline of the common symptoms:

• Weakness, loss of pain and temperature sensation, ataxia or lack of muscle coordination, Horner’s syndrome (a nerve disorder affecting the eyes and face), loss of positional and vibrational sensation, gaze palsy
• Weakness in the muscles around the eyes, loss of facial sensation, dysregulation of the autonomic nervous system, difficulty swallowing, difficulties with speech, vertigo, alterations in taste and hearing
• Choreoathetosis (abnormal involuntary movement), tremors, ataxia, central dysautonomia (problems with nervous system functions), gaze paresis (eye movement disorder), lethargy, and locked-in syndrome (a condition where a person is awake and conscious but can’t move or speak).

During a physical examination, the doctor will check for signs of physical injury, irritation of the meninges (protective membranes covering the brain and spinal cord), and neurological deficits. They will also carry out tests to assess consciousness and mental function, functions of cranial nerves, motor and sensory system, cerebellar signs (signs of damage to the cerebellum, a part of the brain that helps with coordination), and the autonomic system (part of the nervous system that controls involuntary functions like heart rate and digestion).

Testing for Brainstem Stroke (Stroke)

If a doctor suspects you might have had a brainstem stroke, you’ll need to have some tests done. These tests could include checks on things like your blood pressure, pulse rate, and blood oxygen level, as well as other important health indicators. Your doctor might also order a scan of your brain to get a more detailed look at what’s going on. This will often be a CT (computed tomography) scan, which is a type of imaging that can give a clear picture of the brain. MRI (magnetic resonance imaging) can also be used.

In addition to these imaging tests, you might have to take several blood tests. These can check for any other possible medical issues, like problems with your kidney or liver, or potential genetic conditions. A look at your heartbeat might be needed too, using a test called an echocardiogram.

The most important feature to remember about brainstem strokes is that they can cause a very wide range of symptoms. This is because the brainstem controls a lot of different things in your body. Depending on which part of the brainstem is affected, you could experience different signs and symptoms.

For example, occlusion of some specific arteries can cause an altered state of consciousness, sleep disorders, and even breathing difficulties during sleep. Some other potential symptoms include muscle weakness, problems with balance and movement, and difficulty controlling your eyes or face.

After initial tests and evaluation, images of your brain are taken using various techniques depending on the doctors’ first diagnosis. CT scans are the most common imaging technique because of their speed and accessibility. However, an MRI can provide a very detailed image of the brain and might sometimes be preferred, despite being costlier and less common than CT scans.

There are quite a few possible conditions that can show up on these scans, each with its own set of symptoms. Diagnosing which one could be affecting you is a complex task that the doctors will undertake once they have all your test results. Treatment will then be geared towards managing those specific symptoms and preventing any further damage.

Overall, if you or someone you know is experiencing any symptoms related to a stroke, you should seek immediate medical attention. The faster a brainstem stroke is diagnosed, the better the chances are of reducing damage and maximizing recovery.

Treatment Options for Brainstem Stroke (Stroke)

When a patient comes in with symptoms of a stroke, medical professionals need to stabilize their airway, breathing, and circulation first. They’re also given fluids and their blood sugar is normalized. Any fever is treated as necessary and blood pressure is managed carefully. If the patient’s symptoms started within the last 4.5 hours, they might be able to receive an emergency treatment called thrombolysis. If their symptoms started within the last 24 hours, they might be a candidate for a different procedure called mechanical thrombectomy.

Thrombolysis involves an intravenous drug called a tissue plasminogen activator (tPA). This medication can significantly improve patient outcomes when given within 4.5 hours of symptom onset. However, it’s important that specific criteria are met before tPA can be administered, as there are strict age restrictions and blood pressure limits that should not be exceeded. Additionally, certain medical histories, such as previous bleeding incidents or surgeries, may disqualify patients from receiving tPA.

Another treatment includes a procedure called mechanical thrombectomy, which is often used for stroke patients with large blockages in their anterior circulation, although it has been noted that not all patients may see improvements from this treatment.

Using medication to prevent blood clotting can also be effective in patients that suffered from a specific type of stroke called a brainstem stroke. Surgery is typically not recommended for these patients unless they meet very specific criteria.

Thorough follow-up care is also crucial for stroke patients. This includes regular neurological assessments, fluid and blood pressure management, avoiding excessively high body temperatures or glucose levels, preventing infections, and assessing for the risk of falls, pressure sores, and blood clots. Before they leave the hospital, staff should ensure that stroke education has been provided and that a care plan for stroke risk factors and follow-up rehabilitation is in place.

Recent advances in the management of brainstem strokes include efforts in the field of nanoparticles and stem cell combined therapy.

What else can Brainstem Stroke (Stroke) be?

When assessing strokes that occur in the brainstem, doctors need to rule out potential conditions that might cause similar symptoms. These include:

• Cancerous or spreading tumors
• Central pontine myelinolysis, a brain condition caused by severe, rapid correction of low sodium levels
• Acute disseminated encephalomyelitis, a brief but widespread attack of inflammation in the brain and spinal cord
• Multiple sclerosis, a long-term disease that attacks the brain and spinal cord
• Diffuse axonal injury, a type of traumatic brain injury that can’t be seen on standard CT scans
• Conditions that closely resemble stroke symptoms, known as ‘stroke mimics’. These can include:
• Transient ischemic attack, often called a mini-stroke
• Subarachnoid hemorrhage, a type of stroke caused by bleeding in the space surrounding the brain
• Seizures
• Basilar migraine, a headache and migraine disease affecting the back of the head and neck
• Basilar meningitis, a type of meningitis that affects the base of the brain
• Low blood sugar or hypoglycemia
• Electrolyte imbalance, a condition where the balance of minerals in your body is thrown off
• Conversion disorder, a mental condition that can cause physical symptoms

It’s crucial for doctors to consider these alternative diagnoses carefully and perform the necessary investigations to ensure an accurate conclusion.

What to expect with Brainstem Stroke (Stroke)

Stroke is the leading cause of disability and a top cause of death around the world, with increasing rates of occurrence. Early diagnosis and treatment can reduce the risk of permanent health problems. However, the chances of experiencing another stroke in the future stand at between 10% and 15%, underlining the importance of regular medical check-ups. Rehabilitation should also start as early as possible. Those patients with serious neurological issues generally have a worse expectation of recovery. Many factors influence prognosis, including the patient’s age, severity and root cause of the stroke, involved parts of the brain, existing risk factors and overall health, as well as the specific treatment received.

A number of factors can predict poor outcomes from strokes affecting the brainstem, like old age, rapid heart rate, low blood pressure, lack of a pupillary light reflex, and other pupil irregularities. Moreover, a low score on the Glasgow Coma Scale, a large volume of the hematoma, increased body temperature, the need for mechanical breathing support, and high levels of certain blood ratios can also signify worse outcomes.

Traditional treatment strategies for occlusion (blockages) in the basilar artery often result in poor outcomes for around 80% of patients. Death and dependency were seen in about 95% of patients. Occlusion in both the vertebra and basilar arteries, When caused by hardened arteries and clots that come from the heart, respectively, have typically poor outcomes.

Intravenous thrombolysis, a type of clot-busting treatment, is safer and offers better timing in treatment for strokes occurring in the back part of the brain rather than the front. Outcomes are favorable for between 38-49% of patients after this treatment, and the death rate is not significantly different between strokes in the front and back parts of the brain. Similarly, there are no significant differences in treatment timing and results between intra-arterial thrombolysis (another clot-busting treatment) and endovascular thrombectomy (a treatment that physically removes the clot) due largely to other arteries compensating for the blocked ones.’

Recanalization, or the reopening of blocked arteries, can significantly decrease the likelihood of death and undesired outcomes. When compared to clot-dissolving medication alone, endovascular thrombectomy, a type of treatment involving a specialized device to physically remove the clot, is associated with more successful recanalization and improved clinical outcomes.

A study between different management strategies showed varying results depending on the treatment used. One treatment type, percutaneous transluminal angioplasty and stenting, was most effective for blockages in the vertebral and basilar arteries and had lower death rates than another treatment, called mechanical thrombectomy. However, nearly a third of patients still had some disability a year after a stroke, with multiple infarctions and a lack of statin use linked to poor outcomes at 1 year.

The worst prognosis is usually seen in patients with certain types of brain stem stroke, which can lead to death quickly following a specific pattern of breathing problems. Common and consistent factors predicting outcomes include the Glasgow Coma Scale score, a measure of consciousness, as well as the specific location of the stroke and volume of the corresponding hematoma. A low coma scale at presentation, large hematoma and the need for mechanical breathing support all indicate poor prognosis.

A scoring system by Huang et al, which incorporates the hematoma volume and coma scale score was found to be the best evidence in predicting death. In the study, nearly 90% of patients eventually developed hydrocephalus, causing a 100% mortality rate in those managed conservatively. But early intervention markedly improved the clinical outcome. Age and intrusion into the brain’s ventricles, although important, were not independent determinants of early death.

Patients who underwent surgery to remove the hematoma had a much lower death rate than those who didn’t undergo surgery. In fact, an early tracheostomy, which is the surgical creation of an opening into the windpipe, within seven days of admission had a favorable 30-day functional outcome. Monitoring brain activity and physiological response can also predict recovery and the chance of dying in these patients.

Original and modified scoring systems for intracerebral hemorrhage may not apply well to a primary brain stem hemorrhage. Only about 10% of such patients were included in the original hemorrhage score. The primary hemorrhage score also lacks external validation, and the failure to consider early do-not-resuscitate orders was a major flaw.

Possible Complications When Diagnosed with Brainstem Stroke (Stroke)

Complications that might occur after suffering a brainstem stroke are varied. They include different types of neurological deficits, issues with autonomic body functions (dysautonomia) due to an impacted sympathetic tract, and changes in level of alertness or even coma because of the reticular activating system’s involvement. Some of these complications manifest in specific conditions such as the ‘locked-in’ syndrome and the ‘top-of-the-basilar’ syndrome.

• Dysfunction in respiratory control, which could lead to central hypoventilation syndrome or Ondine syndrome due to issues with various respiratory centers
• Problems with blood pressure control due to issues with the Nucleus of tractus solitarius and neurons in the ventrolateral medulla
• Acute hydrocephalus
• Difficulty in swallowing (Dysphagia)
• Difficulty in speaking (Dysarthria)
• Loss of full control of bodily movements (Ataxia)

Patients with a particular condition called Wallenberg syndrome may also experience central pain syndrome in about 25% of cases. Other possible complications can be restless leg syndrome, post-stroke fatigue, and depression.

• Pulmonary aspiration, particularly in patients with medullary and cerebellar strokes
• Deep vein thrombosis and pulmonary embolism
• Bedsores
• Muscle shortening (Contractures)
• Blood poisoning (Sepsis)
• Death

Recovery from Brainstem Stroke (Stroke)

In a study in a recovery clinic, the three most common issues among patients were unsteady movements (68%), one-sided paralysis (70%), and trouble swallowing (40%). Yet, noticeable improvements in these areas were seen. Some patients experienced lung infections due to food or drink entering the airway (15%) and urinary infections (25%). The good news is, 96% of patients were able to return home. People who had a stroke affecting the brain stem generally had a better recovery and survival rate than those who had a stroke affecting one side of the brain. In fact, about 35% of those with a brainstem stroke could live independently within a year, compared to only 22% of those with a hemispheric stroke.

Difficulty in swallowing, a condition known as dysphagia, is experienced by roughly 47% of patients who had a brainstem stroke. It’s best evaluated using a special X-ray technique. Initially, it’s managed by feeding through a tube inserted through the nose. However, in 20% of the patients, feeding tubes inserted directly into the stomach or small intestine are necessary. Patients with this issue should receive specialized training to swallow properly. Techniques that help control mouth and throat movement can also be beneficial with help from speech-language pathologists. In general, the outlook for these patients long-term is positive.

Unsteady movements, or ataxia, is experienced by a significant 86% of patients due to the brain stem’s role in controlling their walking patterns. This can be improved using a technique that encourages patients to repeatedly practice the actions they struggle with. Typical management involves exercises that help improve balance and muscle control, and one popular treatment known as the Bobath method proves to be effective.

Impaired speech, or dysarthria, has been noted in a wide range of 49% to 89% of patients. Control can be regained by improving facial and cheek muscle tone and strength. Slow-speed speech, with frequent pauses, deep breathing, and clear articulation can also be useful. Therapies using mouth reinforcements have proven effective. About 94% of patients have weakened muscles which are then managed through tailored motor training and therapeutic approaches. Double vision is experienced by 38% of patients and can be treated with specific mirrors, plus a combination of blurring, blocking, and suppression techniques. Surgical measures are only considered after 6 months if other treatments have failed.

Preventing Brainstem Stroke (Stroke)

“ACT FAST” is a quick, easy-to-remember guide developed by the American Stroke Association to help individuals identify the early indications of a stroke. This guideline consists of:

• F – Face drooping
• A – Arm Weakness
• S – Speech Difficulty
• T – Time to call 911

Apart from these signs, if someone suddenly exhibits confusion, trouble seeing, numbness, difficulty walking, or experiences a severe headache, it’s critical to quickly contact emergency medical services.

Moreover, it’s just as important for people to manage lifestyle and health factors that can contribute to the likelihood of having a stroke. This includes:

• Giving up smoking
• Drinking alcohol responsibly
• Avoiding drug misuse and addiction
• Controlling conditions like high blood pressure and diabetes
• Maintaining a healthy weight and active lifestyle
• Treating conditions like obstructive sleep apnea syndrome

By doing these, the risk of future strokes can be substantially decreased.