Clinical Presentation of Hypertensive Encephalopathy
Hypertensive encephalopathy presents with severe blood pressure elevation accompanied by neurological symptoms including lethargy, seizures, cortical blindness, or coma in the absence of other explanations. 1
Core Neurological Manifestations
The hallmark neurological symptoms to identify include:
- Altered mental status progressing from somnolence and lethargy to loss of consciousness 1, 2
- Seizures, typically tonic-clonic in nature 1, 2
- Cortical blindness as a distinctive feature 1, 2
- Severe headache as an early warning symptom 1
- Visual disturbances beyond cortical blindness 1
Focal neurological deficits are rare in hypertensive encephalopathy and should immediately raise suspicion for intracranial hemorrhage or ischemic stroke instead. 1, 3 This is a critical distinguishing feature—the presence of focal deficits suggests an alternative diagnosis requiring different management.
Associated Symptoms
Beyond the core neurological features, patients commonly present with:
- Dizziness resulting from impaired cerebral autoregulation 1
- Gastrointestinal complaints including abdominal pain, nausea, and anorexia 1
- Chest pain and dyspnea as part of the broader hypertensive emergency presentation 1
Blood Pressure Characteristics
There is no specific blood pressure threshold that defines hypertensive encephalopathy—the rate of blood pressure increase matters more than the absolute value. 1 While severe elevation is common (often >200/120 mmHg), the diagnosis depends on the presence of neurological symptoms, not a specific number. 1
Retinal Findings
Up to one-third of patients with hypertensive encephalopathy may lack advanced hypertensive retinopathy, making neurological symptoms and imaging the primary diagnostic criteria. 2, 4 When present, fundoscopy may reveal:
Pathophysiological Context
The syndrome occurs when markedly elevated blood pressure overwhelms cerebral autoregulation, leading to increased intracranial pressure and cerebral edema, particularly in posterior brain regions where sympathetic innervation is less pronounced. 1 This manifests as posterior reversible encephalopathy syndrome (PRES) on imaging. 1
Hypertensive encephalopathy occurs in 10-15% of patients with malignant hypertension. 2, 4, 3
Clinical Pitfalls to Avoid
Do not dismiss subtle neurological symptoms like diplopia as "benign" in the setting of elevated blood pressure—any neurological symptom significantly increases the likelihood of intracranial pathology and defines this as a hypertensive emergency. 3 The absence of focal deficits does not exclude hypertensive encephalopathy. 3
Do not rely solely on blood pressure values to make the diagnosis—the clinical presentation with neurological symptoms in the context of severe hypertension is what matters. 1