OVERVIEW

What is brainstem infarction?

Brainstem infarction is an ischemic necrosis of the midbrain, pons, or medulla oblongata caused by the narrowing or blockage of the vertebrobasilar artery and its branches due to atherosclerosis, hypertension, diabetes, and other factors^[1]. It is a type of cerebral infarction. Main symptoms include sensory abnormalities, dizziness, dysphagia, choking while drinking, dysarthria, and unsteady gait.

Brainstem infarction affects patients' quality of life and can be treated with anticoagulants, thrombolytics, antiplatelet agents, lipid-lowering drugs, etc.^[4,5]. If not treated promptly, it may easily lead to cerebral herniation.

Classification of brainstem infarction?

Based on the location of the lesion, it can be classified into three types^[2]:

• Midbrain infarction: The infarct occurs in the midbrain.
• Pontine infarction: The infarct occurs in the pons.
• Medullary infarction: The infarct occurs in the medulla oblongata.

Is brainstem infarction common?

Yes, it is common. Brainstem infarction accounts for about 9%–21% of all cerebral infarctions^[2], meaning 9 to 21 out of 100 cerebral infarction patients have brainstem infarction.

SYMPTOMS

What are the symptoms and manifestations of brainstem infarction?

• Hemiplegic limb weakness: Patients may experience weakness in one side of the hand, arm, or lower limb.
• Sensory disturbances: Patients may exhibit abnormalities in sensation, such as reduced taste, limb numbness, or loss of touch.
• Dysarthria: Patients may have unclear pronunciation, abnormal voice, pitch, or speech speed, and in severe cases, may be completely unable to speak.
• Ataxia: Patients may experience unsteady walking or difficulty performing precise movements.
• Dizziness: A sensation of heaviness in the head, lightheadedness, blurred vision, and unsteadiness while standing.
• Dysphagia and choking on water: Patients may have difficulty swallowing and are prone to choking while eating or drinking.
• Nystagmus: Involuntary back-and-forth movement of the eyes when focusing on an object.

What complications can brainstem infarction cause?

Malnutrition: Due to dysphagia, patients with brainstem infarction are prone to malnutrition, manifested as yellowing of the skin, anemia, etc.^[4].
Brain herniation: Large areas of brainstem infarction can compress brain tissue, leading to brain herniation, which manifests as impaired consciousness, coma, severe headache, etc.^[4].

CAUSES

What are the common causes of brainstem infarction?

• Large artery atherosclerosis: One of the major causes of this condition. Atherosclerosis in large arteries can lead to reduced local blood flow in the brainstem and embolic events in small penetrating vessels, both of which increase the risk of brainstem infarction^[3].
• Cardiogenic embolism: Another cause of this condition. The pathological changes of cardiogenic embolism are similar to thrombosis. When a thrombus dislodges and blocks the vertebrobasilar artery, it causes ischemic changes in the supplied brainstem tissue^[3], leading to brainstem infarction.
• Small artery disease: Due to the lack of collateral circulation, occlusion of small arteries can easily lead to cerebral infarction. If the infarction progresses to the brainstem, it may result in brainstem infarction^[3].
• Arterial dissection: Hypertension and neck trauma can contribute to vertebral artery dissection. Tearing of the arterial wall can form a pseudoaneurysm. If it compresses the brainstem or continues to expand, it may occlude critical branches of the vertebrobasilar artery, causing ischemic changes and leading to brainstem embolism^[3].

What are the high-risk factors for brainstem infarction?

• Disease factors: Conditions such as diabetes, hypertension, coronary heart disease, and hyperlipidemia are high-risk factors for brainstem infarction^[2].
• Smoking: Smoking can cause hypoxic damage to vascular endothelial cells, increase blood viscosity, and deform blood cells, making brainstem infarction more likely^[2].

Which groups are more prone to brainstem infarction?

• Smokers: Due to increased blood viscosity caused by smoking, this group is more susceptible to brainstem infarction.
• Chronic alcohol consumers: Alcohol consumption in this group can contribute to atherosclerosis, increasing the risk of brainstem infarction.
• Hypertension patients: Due to their condition, this group has a higher likelihood of developing brainstem infarction.
• Coronary heart disease patients: Since they already have atherosclerosis, this group is more prone to brainstem infarction.
• Hyperlipidemia patients: Due to their condition, this group has an elevated risk of brainstem infarction.

DIAGNOSIS

How do doctors diagnose brainstem infarction?

Doctors make a comprehensive diagnosis based on the patient's clinical manifestations, medical history, and results from brain MRI, head and neck CT angiography, carotid ultrasound, digital subtraction angiography, and other tests.

What tests are needed to diagnose brainstem infarction?

• Physical examination: Assesses the patient's initial condition by checking for symptoms such as dizziness, difficulty swallowing, choking while drinking, and nystagmus.
• Brain MRI: Clearly shows the specific location of early brainstem infarction.
• Head and neck CT angiography: Evaluates the degree of stenosis in intracranial and extracranial arteries.
• Carotid ultrasound: Examines the structure, function, and blood flow of the carotid arteries.
• Transcranial Doppler ultrasound: Diagnoses stenosis or occlusion of intracranial and extracranial arteries and assesses blood flow.
• Digital subtraction angiography: Clearly visualizes whether there is stenosis or occlusion in major cerebral arteries.

Which diseases can brainstem infarction be easily confused with? How to differentiate them?

Brainstem infarction is often confused with cerebral hemorrhage.
Cerebral hemorrhage: Patients may also experience dizziness, ataxia, and other symptoms. On CT scans, brainstem infarction appears as a hypodense lesion, while cerebral hemorrhage shows as a hyperdense lesion in the brain parenchyma^[4]. The two can be distinguished through CT imaging.

TREATMENT

Which department should I visit for brainstem infarction?

Neurology Department, or Emergency Department for acute cases.

What are the treatment methods for brainstem infarction?

• Thrombolytic drugs: Commonly used drugs include alteplase and urokinase, which can dissolve formed blood clots. Suitable for patients within six hours of onset. Possible side effects include bleeding in the skin, mucous membranes, etc.^[4].
• Anticoagulant drugs: Commonly used drugs include heparin and warfarin, which can prevent the formation of new blood clots and avoid the expansion of the infarction area or recurrent embolism. Suitable for patients in a hypercoagulable state or at risk of deep vein thrombosis and pulmonary embolism. Preventive doses may be used. Possible side effects include gum bleeding, nausea, vomiting, and itchy rashes^[4].
• Antiplatelet drugs: Such as aspirin and clopidogrel, which prevent arterial thrombosis by inhibiting platelet aggregation and reduce the risk of recurrence. For acute cerebral infarction patients, aspirin should be taken within 48 hours. Clopidogrel can be used as an alternative for those allergic to aspirin. Possible side effects of aspirin include hearing loss, tinnitus, and hives; clopidogrel may cause bleeding^[4].
• Lipid-lowering therapy: Commonly used drugs include atorvastatin, which lowers cholesterol and has neuroprotective effects, suitable for cerebral infarction patients. Possible side effects include gastrointestinal discomfort, diarrhea, headache, and rashes^[5].

Can brainstem infarction be cured?

Brainstem infarction generally cannot be completely cured. With proper treatment, clinical symptoms can be alleviated, and rehabilitation therapy can help maximize the recovery of neurological function.

DIET & LIFESTYLE

What should patients with brainstem infarction pay attention to in their diet?

• Reduce the intake of high-fat, high-calorie foods such as fried dough sticks, pizza, potato chips, and cream to avoid worsening atherosclerosis.
• Increase the intake of vegetables and high-fiber foods such as celery, rapeseed, and pumpkin. They can be blended into vegetable juice to reduce swallowing difficulties and aid recovery.

What should patients with brainstem infarction pay attention to in daily life?

• Avoid early and excessive exercise within 24 hours of onset. Activities like sitting, standing, and walking should begin as early as possible once the condition stabilizes^[4].
• Bedridden patients should pay attention to body positioning, avoiding lying on the paralyzed side.
• Turn and clean the body frequently to maintain hygiene and prevent pressure sores.
• Strictly follow medical advice for treatment and follow-up visits. Do not reduce, stop, or change medications without permission.

Do brainstem infarction patients need follow-up examinations? How?

Yes, follow-up examinations are necessary, typically involving cranial MRI and vascular assessment.

PREVENTION

Can Brainstem Infarction Be Prevented? How to Prevent It?

Yes, it can be prevented.

• Diabetes, hypertension, and coronary heart disease are high-risk factors for brainstem infarction, so actively treating these underlying conditions can help prevent it to some extent.
• Developing healthy eating habits, maintaining a balanced diet, and exercising regularly can also contribute to preventing brainstem infarction.