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Authors

  1. Steuber, Allison MSN, RN, CEN

Article Content

MR. M, AGE 21, presented to the ED via emergency medical services with new-onset seizures. Mr. M had had a few drinks with friends the night before, but came home without signs of intoxication or changes in mental status. In the morning, he'd awoken with a headache and vomiting. When his family saw him having a generalized tonic-clonic seizure, they called 911. En route to the ED, the patient had another seizure and remained in a postictal state. The patient had a third seizure on arrival at the ED.

  
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Initially puzzled, healthcare providers eventually diagnosed reversible posterior leukoencephalopathy syndrome (RPLS). This article details causes and clinical manifestations, and discusses emergency interventions for this potentially life-threatening neurologic syndrome.

 

Looking into RPLS

Although the pathogenesis of RPLS isn't clear, it appears to be related to disordered cerebral autoregulation and endothelial dysfunction. The most widely accepted theory of RPLS is failure of normal autoregulation, which maintains constant cerebral blood flow over a range of systemic BP, resulting in increased vascular permeability and cerebral edema.1 (See Understanding cerebral autoregulation.)

 

Signs and symptoms such as these typically develop rapidly, peaking within 12 to 48 hours:1

 

* significantly elevated BP with signs or symptoms of acute, ongoing target-organ damage (hypertensive emergency)

 

* nonlocalized, moderate to severe headaches that are typically constant and don't respond to analgesics

 

* altered level of consciousness that can include confusion, agitation, stupor, or coma

 

* visual disturbances, such as vision loss, hemianopia, and visual hallucinations

 

* seizures, which are usually generalized tonic-clonic.2-42-4

 

 

Although seizures occur in about 90% of patients with RPLS, reaching a diagnosis is often challenging when patients first present to the ED. In addition, over 1 million patients are seen in EDs across the country each year for a chief complaint of headaches.5 Unless other signs and symptoms associated with RPLS are recognized, the diagnosis can be easily overlooked.

 

The most common risk factors for RPLS seem to be abrupt severe arterial hypertension, impaired renal function, preeclampsia or eclampsia, immunosuppressive drugs, transplantation, and autoimmune diseases.1

 

Patient history

The patient's family reported that Mr. M had no significant health history, including no history of seizures or intracranial infection. He'd been diagnosed with "borderline hypertension" and was to follow up with his primary care provider but hadn't done so to their knowledge.

 

He takes no routine medications or supplements and has no known allergies. Mr. M drinks some socially and doesn't smoke or use any illicit drugs to his parents' knowledge. His parents are unaware of any recent illness or injury to Mr. M and deny any family history of seizures.

 

Physical assessment findings

The patient had no obvious injuries or signs of trauma. Vital signs were temperature, 98.4[degrees] F (36.9[degrees] C); heart rate, 110, sinus tachycardia; respiratory rate, 20; BP, 190/130 (mean arterial pressure, 150); and SpO2, 94% on 100% non-rebreather mask.

 

His pupils were 6 mm, equal, round, and reactive to light. Mr. M was moving all four extremities spontaneously, but he couldn't follow simple commands. No other abnormal physical assessment findings were noted.

 

Diagnostic studies

Mr. M's urine and drug screens were negative. Other lab test results were within normal range except for an elevated serum creatinine of 1.9 mg/dL (normal, 0.7-1.3 mg/dL). Because many serious neurologic disorders such as subarachnoid hemorrhage can cause new-onset seizures in an adult, he underwent a stat noncontrast computed tomography (CT) scan of the head. CT demonstrated symmetric white matter edema in the posterior cerebral hemispheres, particularly in the parieto-occipital regions. Magnetic resonance imaging (MRI) findings demonstrated vasogenic edema mostly localized to the posterior cerebral hemispheres. Both CT and MRI findings were consistent with RPLS.4

 

Continuous electroencephalography demonstrated no evidence of electrographic seizures.

 

Initial steps

Immediate ED interventions included airway management, antiepileptic drug (AED) administration, aggressive antihypertensive therapy, and a neurology consult.

 

Due to a prolonged postictal period and the risk of airway compromise, the patient was electively endotracheally intubated, placed on mechanical ventilation, and started on I.V. propofol and I.V. fentanyl infusions for sedation and comfort while intubated. I.V. lorazepam was administered for seizure activity. The hypertensive emergency was managed with multiple doses of I.V. labetalol to reduce mean arterial pressure gradually by about 10% to 20% in the first hour and by a further 5% to 15% over the next 23 hours.4

 

Further management

I.V. levetiracetam, an AED, was administered to prevent further seizure activity and Mr. M's hourly urine output was carefully monitored. Other priority nursing interventions included frequent neurologic assessments and continuous BP monitoring to assess for any deterioration in mental status, new neurologic deficits, and any changes in vital signs.

 

Treatment of the suspected underlying cause is recommended for managing RPLS. For example, medical management of hypertension, dosage reduction or termination of chemotherapy, or administration of I.V. magnesium sulfate to treat seizures in the setting of eclampsia should be considered.1 For this patient, determining what caused his renal dysfunction and hypertension is essential for choosing an appropriate treatment plan.

 

Mr. M was evaluated by a nephrologist in the ICU and underwent a renal biopsy, which demonstrated membranoproliferative glomerulonephritis. Whether glomerulonephritis caused the hypertension or the hypertension caused the glomerulonephritis wasn't clear.

 

After appropriate management, Mr. M's BP was reduced to 113/65 and his serum creatinine level improved to 1.6 mg/dL. As Mr. M's BP improved, his neurologic status improved as well. He became cooperative, followed commands, and was successfully extubated within 48 hours of admission to the ED. Mr. M was transferred out of the ICU to an intermediate care unit for continued monitoring until he was discharged from the hospital 6 days after admission. At discharge, his headache had resolved and his mental status had returned to normal.

 

The neurologist recommended that Mr. M remain on AED therapy after discharge until repeat imaging demonstrated complete resolution of RPLS. Follow-up was arranged with the patient's primary care physician, nephrologist, and neurologist.

 

Positive outcomes

The good news? Usually RPLS is reversible and patients have excellent short- and long-term outcomes. Signs and symptoms resolve within a week when treated early and aggressively.1

 

In the acute care setting, many patients are evaluated each year with headaches and new-onset seizures. Clinicians need to consider RPLS as a differential diagnosis.

 

Understanding cerebral autoregulation

Cerebral autoregulation, a major homeostatic and protective mechanism, is the brain's ability to maintain a constant blood flow in spite of changes in arterial perfusion pressure. In healthy people, autoregulation operates within a mean arterial BP of 60 to 150 mm Hg; below 60 mm Hg, cerebral blood flow (CBF) decreases and above 150 mm Hg, CBF increases. Autoregulation generally requires an intracranial pressure of less than 40 mm Hg.

 

Autoregulation, which takes place in large and small arterioles, provides a constant CBF by adjusting the diameter of blood vessels. Arterioles' smooth muscles respond to stretch receptors and intraluminal pressure; vasoconstriction increases intraluminal pressure and vasodilation decreases intraluminal pressure.

 

Source: Hickey JV. The Clinical Practice of Neurological and Neurosurgical Nursing. 7th ed. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams and Wilkins; 2014.

 

REFERENCES

 

1. Roth C, Ferbert A. The posterior reversible encephalopathy syndrome: what's certain, what's new. Pract Neurol. 2011;11(3):136-144. [Context Link]

 

2. Min Z, Gnann JW Jr. Reversible posterior leukoencephalopathy syndrome. Intern Emerg Med. 2014;9(3):341-342. [Context Link]

 

3. Wright KL, Polito MH, French AE. Posterior reversible encephalopathy syndrome: a case study. Am J Nurs. 2012;112(5):36-40.

 

4. Neill TA. Reversible posterior leukoencephalopathy syndrome. 2015. http://www.uptodate.com. [Context Link]

 

5. Pallin DJ, Goldstein JN, Moussally JS, Pelletier AJ, Green AR, Camargo CA Jr. Seizure visits in US emergency departments: epidemiology and potential disparities in care. Int J Emerg Med. 2008;1(2):97-105. [Context Link]