Can hypertension cause seizure activity?

Hypertension and Seizure Activity

Yes, severe hypertension can cause seizure activity, particularly in the context of hypertensive encephalopathy, which is characterized by severe hypertension and seizures, lethargy, cortical blindness, and coma in the absence of alternative explanations. 1

Pathophysiological Mechanisms

• Hypertensive encephalopathy occurs in 10-15% of patients presenting with malignant hypertension, though advanced hypertensive retinopathy may be lacking in up to one-third of these patients 1
• When blood pressure is markedly elevated and cerebral autoregulation fails, cerebral edema may develop, especially in the posterior areas of the brain, leading to seizure activity 2
• Autoregulation failure is at the foundation of target organ damage associated with malignant hypertension and can result in hypertensive encephalopathy 1
• The marked activation of the renin-angiotensin system is often present in malignant hypertension and is associated with the degree of microvascular damage 1

Clinical Presentations

• Seizures are among the most alarming symptoms of hypertensive encephalopathy, but more subtle neurological features can be present at an earlier stage 1
• Hypertensive encephalopathy is characterized by severe hypertension (usually >200/120 mmHg) and one or more of the following: seizures, lethargy, cortical blindness, and coma 1
• Clinical presentations of hypertensive cerebellar lesions may include headache, visual disturbances, and focal neurological symptoms that can progress to seizures 2

Risk Factors

• Left ventricular hypertrophy without diuretic treatment was associated with an 11-fold increased risk of unprovoked seizure in older adults 3
• History of hypertension is significantly associated with unprovoked seizures, even after adjustment for antecedent stroke and other potential confounders 4
• There is marked synergism between history of stroke and history of hypertension; subjects with a history of both had a fourfold increase in seizure risk 4

Diagnostic Approach

• The diagnosis of hypertensive encephalopathy principally relies on the presence of neurological symptoms (including seizures) supported by additional imaging 1
• MRI is the preferred imaging modality for hypertensive encephalopathy, typically showing increased signal intensity on T2-weighted or FLAIR imaging 2
• CT scanning is useful to exclude intracranial hemorrhage and can identify cerebellar hematomas that may be associated with seizure activity 2

Management

• Hypertensive encephalopathy requires immediate BP reduction to limit extension or promote regression of target organ damage 1
• For hypertensive encephalopathy, the timeline for blood pressure reduction is immediate, with a target of reducing mean arterial pressure by 20-25% 1
• In cases where hypertensive encephalopathy occurs with seizures while on medications like Epoetin, the medication should be discontinued until clinical stability is achieved 1

Hypertension-Related Conditions Associated with Seizures

• Malignant hypertension: Severe BP elevation (usually >200/120 mmHg) associated with advanced retinopathy 1
• Posterior reversible encephalopathy syndrome (PRES): An acute condition, often caused by a hypertensive crisis, associated with the occurrence of acute symptomatic seizures 5
• Hypertension-related small vessel disease: Has been demonstrated to play a role in adult-onset epilepsy 5

Prevention

• Effective antihypertensive therapy strongly reduces the risk of developing significant white matter changes that could lead to seizures 2
• Diuretic treatment may protect against the increased risk of unprovoked seizures in patients with left ventricular hypertrophy 3
• The optimal blood pressure range to prevent cognitive decline and cerebrovascular damage in older individuals is thought to be 135-150 mmHg systolic and 70-79 mmHg diastolic 2

Caveats and Pitfalls

• Not all seizures in hypertensive patients are directly caused by hypertension; other etiologies should be considered 6
• Transient increases in blood pressure can occur during seizures due to autonomic activation, making it important to distinguish whether hypertension is the cause or effect of seizure activity 6
• Cerebellar lesions due to hypertension may initially be mistaken for other conditions such as multiple sclerosis, though hypertensive lesions typically have different characteristics 2