What is Cerebellar Hematoma?
A cerebellar hemorrhage, also known as a hematoma, is a type of bleeding in the brain that happens in an area known as the posterior fossa or the cerebellum. It makes up about 9% to 10% of all instances of brain bleeds. The posterior fossa is a small area in the skull which houses the brainstem and the cerebellum. Now, when a mass like a hemorrhage grows in this area, particularly affecting the brainstem and another structure known as the 4th ventricle, it can block the normal movement of brain fluid. This blockage can lead to a condition like hydrocephalus, increased pressure inside the skull, and the onset of symptoms.
Cerebellar hemorrhage can occur spontaneously, can be a result of a stroke, or can be caused by injury. It is most common in middle-aged and older people. Patients usually have pre-existing risk factors that lead to these types of bleeds, such as high blood pressure or microscopic blood vessel disease. What symptoms patients show depends on factors like the size and location of the bleed within the brain, as well as the location and extent of swelling in related structures within the posterior fossa.
Typically, a CT scan without contrast is first used for imaging. The treatment could range from a watchful waiting approach to immediate surgical intervention, with the timing of any surgery being optimally determined.
What Causes Cerebellar Hematoma?
The most typical non-injury related cause for bleeding in the cerebellum, like all brain bleeding, is a condition wherein high blood pressure leads to the formation of small bulges in the blood vessels, which can burst. This type of bleeding due to high blood pressure usually happens in middle-aged or older people, and it often starts in a part of the cerebellum called the dentate nucleus and then spreads outwards, due to these tiny bulges bursting on the small penetrating vessels.
There are other reasons why the cerebellum might bleed, including injury, issues with the clotting of the blood due to liver disease or other blood disorders, certain medications that thin the blood, a stroke turning from blockage to bleeding, a specific condition where protein buildup in the brain’s arteries can lead to rupturing, unusual connections between arteries and veins, infections of the brain, cancer of the brain, usage of drugs like cocaine and amphetamines, aneurysms in the back part of the brain, or bleeding after a surgical procedure in the brain.
Primary tumors in the central nervous system (the brain and spine) that are most likely to experience bleeding are glioblastomas. Cancers that have spread to the brain and are most at risk of bleeding include those starting in the lung, breast, kidney, and skin cancer, marked as melanomas.
In younger people, cerebellum bleeding might be due to substance abuse, trauma, bulging or rupture of blood vessels in the brain, or the unusual linking between arteries and veins.
Risk Factors and Frequency for Cerebellar Hematoma
Nontraumatic intracranial hemorrhage, or brain bleeding that isn’t caused by injury, varies by both race and age. It accounts for 9% to 27% of strokes across the world, happening at a rate of 12 to 31 cases per 100,000 people each year. A type of this condition, cerebellar hemorrhage, forms about 10% of all intracranial hemorrhages and only 1% to 2% of all strokes annually.
- The frequency of intracranial hemorrhage rises with age, doubling every 10 years once an individual turns 35.
- The occurrence is highest in Asian populations, followed by Black populations, and is lowest in the White population.
Signs and Symptoms of Cerebellar Hematoma
A sudden cerebellar hemorrhage can cause different symptoms depending on its size and location. If the hemorrhage is small, you might experience a headache, nausea, vomiting, dizziness, or uncoordinated movements. If it’s large, you might have changes to your consciousness or even lose responsiveness. Symptoms might appear suddenly, get worse when the hemorrhage grows, or happen during stressful situations or heavy physical activity. It’s essential to know your medical history, including high blood pressure, problems with blood clotting (including those caused by medications), head trauma, history of aneurysms or arteriovenous malformations in the brain, cancer history, and use of certain drugs like cocaine and amphetamines. The most common symptoms in decreasing order of frequency include:
- Sudden onset of headache
- Nausea and vomiting
- Difficulty with walking (truncal ataxia)
- Dizziness and vertigo
- Speech difficulties (dysarthria)
- Neck pain or stiffness
- Loss or change in consciousness
Your physical exam might vary as well, and again, it depends on the location of the hemorrhage. You might be awake or unresponsive. Signs related to the cerebellar region might include any of the following:
- Uncoordinated movements of the arms and legs (limb ataxia)
- Speech difficulties (dysarthria)
- Involuntary eye movements (nystagmus)
- Abnormal gaze or facial weakness on the side of the hemorrhage (cranial nerve palsy)
- Unusual gait
Testing for Cerebellar Hematoma
If a person is showing signs that they might have a cerebellar hemorrhage, or bleeding in the brain, a non-contrast head CT scan is usually the go-to method for examining this. This type of imaging is fast and widely available. Most of the times, the CT scan can easily spot the hemorrhage as it appears as lighter, or hyperdense, spots in the cerebellum, the part of the brain being looked at.
However, sometimes, there can be confusions. Dense calcification, or hardening, of a certain area called the dentate nucleus can look like a hemorrhage. But, if this spot doesn’t seem to be causing a mass effect, has well-defined borders, and appears on both sides, then it is less likely to be a hemorrhage and more likely to be calcification. If contrast, a special dye, was used in a previous procedure, it can make the area appear dense in the scan and may clash with a cerebellar hemorrhage. Yet, a different kind of CT scan, called a dual-energy CT, can help to distinguish between the two.
If additional clarification is needed, other imaging options, such as a CT angiogram, MRI, MRA, or angiography could be used. These methods can give further details about the potential hemorrhage.
Treatment Options for Cerebellar Hematoma
The treatment of a cerebellar hemorrhage, which is a type of stroke caused by bleeding in the cerebellum, depends on the size of the hemorrhage and the patient’s symptoms. In some severe cases where the patient’s consciousness level is significantly reduced, medical professionals may need to assist with breathing by inserting a tube into the windpipe.
Medical experts should be immediately consulted after a cerebellar hemorrhage is diagnosed in order to provide the best possible care. Small hemorrhages without a lot of swelling can often be treated with supportive care in a critical care unit where the patient can be closely monitored. Larger hemorrhages, typically when they are more than 3 to 4 cm, may need surgery to remove the blood, especially if there’s swelling, spread of the bleeding into the brain ventricles, displacement of the brainstem, or a condition called hydrocephalus. Medications like steroids don’t prove beneficial for cerebellar hemorrhages.
Patients with cerebellar hemorrhage may experience a sudden increase in blood pressure. Careful management is required to limit the growth of the hemorrhage and any increase in pressure inside the skull while ensuring the brain gets enough blood. Medical guidelines suggest to safely lower blood pressure below certain thresholds. Elevated body temperature should be avoided as it can worsen the outcome in brain injuries, and normal glucose levels should also be maintained to ensure the best potential outcome for the patient.
All medications that prevent blood clotting should be immediately stopped in cases of cerebellar hemorrhages. The normal fluid level in the body should be maintained and the levels of essential substances in the blood, like sodium, potassium, and magnesium, should be appropriately adjusted. Certain heart rhythm disturbances can occur in patients with brain injuries, so keeping potassium and magnesium levels within the recommended ranges becomes crucial.
Patients who are relying on medications to prevent blood clotting may require specific treatments to counteract these effects. For patients on a medication called warfarin, vitamin K and factors to help blood clot again maybe administered. For patients on newer oral anticoagulants, similar treatments may be tried, although the evidence supporting this is limited. Patients on antiplatelet medications, or with a low platelet count, may need platelet transfusion, particularly if they have severe bleeding or need surgery, though the benefits of this treatment are still uncertain.
What else can Cerebellar Hematoma be?
When a person suddenly experiences symptoms like headaches, nausea, vomiting, dizziness, or a spinning sensation (vertigo), the causes can range between brain-related (central) and ear-related (peripheral) conditions.
Central causes may include:
- An unexpected damaging disease like multiple sclerosis (MS) or encephalitis
- An addiction to alcohol
- Bleeding in the small brain (cerebellar hemorrhage)
- A stroke in the small brain (cerebellar infarction)
- A growth or tumor in the small brain (cerebellar neoplasm)
- Infection in the small brain (cerebellitis)
- Illegal drug use
- Overdosing on certain medications (like phenytoin or carbamazepine)
Peripheral causes might involve:
- A non-serious type of vertigo that comes and goes (benign paroxysmal positional vertigo (BPPV))
- An inflammation in the inner ear (labyrinthitis)
- Meniere’s disease, a disorder of the inner ear
- Inflammation of the nerves that connect the inner ear to the brain (vestibular neuronitis)
What to expect with Cerebellar Hematoma
The death rate due to cerebellar hemorrhage can vary, going from 25% to as high as 57%. The success of surgery mostly depends on the patient’s health condition before the procedure, but the outcomes are generally positive in more than half of the cases. Therefore, it’s generally advised that unless the patient has numerous other health issues, surgery should be considered, even if they have a poor neurological condition before the operation.
Possible Complications When Diagnosed with Cerebellar Hematoma
A serious brain bleed in the cerebellum can cause swelling and pressure build-up, which unfortunately opens up the possibility of several complications. These can include pressure on the brainstem, herniation of the cerebellum, compression of the fourth ventricle leading to blocked fluid flow in the brain, hemorrhage extending into the brain’s ventricular system and recurring bleeds, often within the first day.
There are primarily two ways to handle the pressure build-up from a cerebellar bleed – the use of high salt solutions (hyperosmolar agents) or surgery to relieve pressure (decompressive surgery).
Osmolar therapy functions by limiting the swelling caused by the bleed and the fluid build-up. This is done by increasing the concentration of substances in the blood, encouraging water to move from the swollen tissue into the bloodstream, effectively reducing the swelling and pressure in the brain. There is no clear evidence pointing towards hypertonic saline being better than mannitol for treating brain bleeds. The salt solution concentrations typically used are 3% (250 mL in quantity), 10% (75 to 150 mL), and 23.4% (30 mL). Doses and continuous drips aim at sodium levels of 145 to 155 mmol/L and blood osmolality of 310 to 320 mOsm/kg. But complications, including low blood pressure, lung fluid overload, heart failure, coagulopathy, low potassium levels, breakdown of red blood cells within the blood vessels, and brain damage, though they are rare. Mannitol is a sugar alcohol used as a diuretic and is typically given as a 1 to 2 g/kg dose (20% concentration) with additional doses of 0.5 g/kg every 4 to 6 hours. It’s essential to maintain normal body fluid levels during its use, and caution should be taken in patients with kidney failure, as mannitol may cause fluid overload requiring dialysis. The blood osmolality should be kept under 320 mOsm/kg to prevent kidney toxicity.
The preferred surgical strategy in such cases is the removal of a part of the skull at the back of the head to relieve pressure, with the evacuation of the hematoma or the blood clot. Surgery becomes necessary when the patient’s neurological health continues to worsen due to pressure on the brainstem or blocked fluid flow in the brain, thanks to the pressure from the hemorrhage and swelling. An external ventricular drain (EVD) can be one alternative or additional step to surgery, used to treat blocked fluid flow in the brain. Deciding who should undergo surgery and/or have an EVD is based on the patient’s symptoms and the appearance of the brain bleed on imaging, like the size of the hematoma, expansion into the ventricular system, blocked fluid flow in the brain, pressure on the brainstem, and obliteration of the cisterns. Hematomas less than 3 cm with no signs of brainstem pressure or blocked fluid flow can be managed with close monitoring in an intensive care setting without the need for surgery. For patients with smaller bleeds, a burr-hole aspiration under stereotactic guidance is another option.
Preventing Cerebellar Hematoma
Most bleeding in the cerebellum, a part of the brain, happens due to high blood pressure. People with high blood pressure should be properly informed about the potential risks and problems that can occur if their condition is not well-managed. These individuals should be urged to get medical help immediately if they start to experience concerning symptoms.
