Hypertensive Encephalopathy

Aka: Hypertensive Encephalopathy, Posterior Reversible Encephalopathy Syndrome, Posterior Leukoencephalopathy Syndrome, PRES, RPLS

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II. Pathophysiology

  1. Cerebral perfusion is autoregulated via arteriole constriction and dilation
    1. Blood Pressure may exceed autoregulation and allow fluid and blood to leak across the blood brain barrier
    2. Results in Hypertension-induced cerebral edema and micro-Hemorrhages
  2. Blood Pressure thresholds vary based on chronicity of Severe Hypertension
    1. Chronic Severe Hypertension is compensated and encephalopathy occurs at a higher Blood Pressure
    2. Acute Severe Hypertension is more likely to cause encephalopathy at a lower Blood Pressure (esp children)
      1. Underlying conditions (e.g. Vasculitis) or new medications may predispose to rapid onset Severe Hypertension

III. Symptoms

  1. Headache
  2. Visual changes
  3. Vomiting
  4. Dizziness

IV. Signs

  1. Extremely high Blood Pressure
  2. Altered Level of Consciousness or confusion
  3. Lethargy
  4. Seizures

V. Labs

  1. See Altered Level of Consciousness

VI. Imaging

  1. MRI Brain
    1. Abnormal in Reversible Posterior Leukoencephalopathy Syndrome (RPLS, PRES)
    2. Symmetric white matter edema in posterior Cerebral Hemispheres

VII. Diagnosis

  1. Clinical diagnosis of exclusion (although RPLS or PRES may be diagnosed on MRI)
    1. Evaluate for other causes of Altered Level of Consciousness
  2. Hypertensive Encephalopathy typically improves with Blood Pressure lowering (even 10-20%)
    1. Other causes of Altered Level of Consciousness and Hypertension (e.g. CVA) do not improve as readily
  3. Asymptomatic Hypertension may present with very high Blood Pressure and mild Headache
    1. However, contrast with Hypertensive Encephalopathy in which patient's appear ill and are confused

VIII. Differential Diagnosis

  1. See Altered Level of Consiousness
  2. Cerebrovascular Accident
  3. Eclampsia
  4. Encephalitis
  5. Hepatic Encephalopathy
  6. Uremic Encephalopathy
  7. Neuroleptic Malignant Syndrome
  8. Serotonin Syndrome
  9. Anticholingeric Syndrome
  10. Cytotoxic Chemotherapy reaction (esp. Serum Creatinine >1.8 mg/dl and Fluid Overload)

IX. Management

  1. See Hypertensive Emergency for agents to emergently lower Blood Pressure
  2. Nicardipine is typically recommended in Hypertensive Encephalopathy
  3. Lower Blood Pressure by 10-25% within first hour of presentation
    1. Further lowering as needed

X. Prognosis

  1. Fully reversible in most cases within days to weeks
  2. In one study, nearly 25% died and another subset had permanent neurologic dysfunction
    1. Covarrubias (2002) Am J Neuroradiol 23(6): 1038-48 +PMID:12063238 [PubMed]

XI. References

  1. Swaminathan and Weingart in Herbert (2020) EM:Rap 20(2): 3-4
  2. Elliott and Varon (2016) Evaluation and Treatment of Hypertensive Emergencies, UpToDate, accessed 12/28/2016
  3. Neill (2016) Reversible Posterior Leukoencephalopathy Syndrome, UpToDate, accessed 12/28/2016
  4. Staykov (2012) J Intensive Care Med 27(1): 11-24 +PMID:21257628 [PubMed]

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