Case Report

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American Journal of Emergency Medicine

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posterior reversible encephalopathy syndrome: a unique presentation?,??

Abstract

We present a case of a patient presenting with posterior reversible encephalopathy syndrome to the emergency department. We discuss the various symptoms that lead to the identification of posterior reversible encephalopathy syndrome and the important clinical clues. Posterior reversible encephalopathy syndrome is a very uncommon diagnosis/clinical presentation that requires the understanding of the condition and awareness in distinct/specific patient populations. Without this understanding, the diagnosis may be missed and appropriate management delayed.

A 35-year-old woman was brought to the emergency department (ED) by ambulance complaining of itching and swelling in her face after taking ibuprofen 600 mg for a headache several hours before. She denied any difficulty breathing or oral pharyngeal involvement. She stated that she felt slightly better after receiving diphenhydra- mine from the emergency medical services (EMS) personnel. Her vital signs on arrival were blood pressure of 157/97 mm Hg, pulse of 56 beats per minute, respiratory rate of 12 breaths per minute, temperature of 97.6?F, and pulse oximetry of 98% in room air. Her physical examination was significant for bilateral pedal edema with the patient improving as well as a lack of skin rash or oral pharyngeal swelling. She was given famotidine and methylprednisone in the ED, and after several hours of observation, she was discharged home with caution to avoid nonsteroidal anti-inflammatory drugs.

Approximately 11 hours after discharge, the patient again called 911, requesting an ambulance and complaining of a Severe headache. During transport, the paramedics witnessed a seizure that lasted approximately 45 seconds. The patient was extremely combative upon arrival to the ED and was unable to cooperate with History taking. Her teenage son accompanied her and stated that his mother had had an increasing headache for 2 days. He denied any other medical history. Just before calling EMS, she complained that the headache was much worse, and the patient complained of Blurred vision. Vital signs on arrival were blood pressure of 133/61 mm Hg, pulse of121 beats per minute, and pulse oximetry of 98% in room air. Respirations and temperature were not obtained immediately secondary to patient’s extreme combativeness. Because of the patient’s mental status, it was elected to intubate the patient in the ED both for protection of the airway and to facilitate sedation so that a computed tomographic scan of the brain could be obtained. The subsequent scan revealed no acute intracranial pathology and no mass lesion, mass effect, or Midline shift.

At this time, a discussion was held with the patient’s son and other family members who had arrived, and it was revealed that the patient

? Conflicts of interest: None.

?? Author contributions: N/A.

was 9 days status post spontaneous delivery of twins. With this new information, postpartum complications were added to the differential diagnosis, and the patient was treated with magnesium sulfate 4 g intravenously. In addition, neurology and obstetrics were both consulted. In the interim, the patient also received vancomycin, ceftriaxone, and acyclovir to cover for both meningitis and endometritis (patient was group B Streptococcus positive on vaginal cultures obtained during her prenatal care). In addition to the computed tomographic scan, a lumbar puncture was performed and revealed no abnormalities. With the exception of a white blood cell count of 13.4 (neutrophils of 69%, lymphocytes of 27%), the patient’s blood count, chemistry panel, and liver function panel were all within normal limits. The urinalysis was significant for a protein level of 30 mg/dL. A magnetic resonance imaging (MRI) scan of the brain obtained 24 hours later revealed bilateral symmetric white matter change posteriorly, most compatible with Posterior Reversible Encephalopathy Syndrome (Fig. 1). In addition, there were bilateral patchy white matter changes more anteriorly in the frontal lobes, which may have represented sequela of PRES or transitory changes secondary to seizures (Fig. 2).

The patient was extubated on hospital day 2 and was discharged on hospital day 4 with full neurologic function.

First described in 1996 by Hinchey as reversible posterior leucoen- cephalopathic syndrome and changed to its current name by Casey in 2000 [1], PRES continues to be a diagnosis that few clinicians consider in their differential diagnosis. The typical constellation of symptoms attributed to PRES includes altered mental status, vision changes, headache, and seizures [2] can be found in other disease entities. The T2- or FLAIR-weighted images on MRI reveal hyperintense lesions bilater- ally in the parietooccipital lobes and validate the final diagnosis of PRES [3]. A host of underlying clinical conditions have been linked to PRES, including [4-6]:

• Hypertensive emergency
• Preeclampsia/eclampsia
• Renal disease
• Immunosuppressive medications
• autoimmune disorders
• Transplantation (both solid organ and allogeneic bone marrow)

In the original research published by Hinchey, eclampsia was identified as the inciting factor in 20% of patients diagnosed with PRES. In addition, patients who develop eclampsia with in prior pregnancies are at increased risk for developing recurrent eclampsia with future pregnancies. Similarly, patients can also develop recurrent PRES. Sweany proposed an incidence of 3.8% for recurrent PRES in his review of 78 patients with PRES.

Far from being simply an interesting incidental finding, the diagnosis of PRES carries significant clinical implications. Despite being part of the official name of this syndrome, the reversibility is contingent upon Prompt diagnosis and appropriate treatment.

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Fig. 1. Magnetic resonance imaging of brain showing changes in the posterior lobe consistent with PRES.

Fig. 2. Magnetic resonance imaging of the brain showing changes in the frontal lobe, which may represent sequela of PRES or transitory changes secondary to seizures.

Indeed, yet another name change for this entity has been proposed, from “posterior” to “potentially reversible encephalopathic syn- drome” to better emphasize the clinical course as well as acknowledge the varied radiologic presentations [7]. Both inciting and anatomical factors have been linked to the degree of reversibility. Patients who present with eclampsia and PRES have the best recovery; hyperten- sion and chemotherapy have also been identified as underlying pathologies, which are linked to a high degree of reversibility. Lesions in the brain stem and deep white matter are associated with worse prognoses, whereas patients with lesions in the cortex and subcortex tend to have more favorable outcomes [5].

Treatment for PRES must focus on identification and treatment of the underlying condition and treating and preventing seizures and strict blood pressure control. If drugs such as FK-506 or other immunosuppressants are the likely culprit, they must be promptly stopped. Term or near-term pregnancies may be delivered, but in cases where fetal viability is at question, medical management may be appropriate. Eclamptic seizures are treated with magnesium sulfate, whereas seizures of other etiologies can be treated with benzodiaz- epines such as lorazepam or diazepam. Refractory seizures may be treated with barbiturates such as phenytoin or phenobarbital. Nicardipine and labetalol are common agents used for blood pressure control given their quick onset and easy titratibility. Goal systolic blood pressures should be maintained at approximately 105 to 125 mm Hg [4]. Because of concern for worsening of edema, nitroglycerin should be avoided, especially in eclamptic patients [8].

Awareness of PRES is crucial for emergency physicians, as prompt identification and treatment can have profound impacts upon patient’s long-term neurologic function. The emergency physician

should have a low threshold to obtain an MRI on any patient with new onset altered mental status, seizures, and vision changes, especially if the history reveals use of immunosuppressants or transplantation, eclampsia, renal disease, or malignant hypertension.

Christopher R. Lang MD Nathalie Coeller MD

Department of Emergency Medicine George Washington University

Washington, DC, USA E-mail address: crlang@yahoo.com

http://dx.doi.org/10.1016/j.ajem.2013.05.018

References

1. Casey S. Posterior Reversible Encephalopathy Syndrome: Utility of Fluid-attenuated Inversion Recovery MR imaging in the Detection of Cortical and Subcortical Lesions. American Journal of Neuroradiology 2000;21:1199-206.
2. Hinchey H. A reversible posterior leukoencephalopathy syndrome. N Engl J Med 1996;334:494-500.
3. Finocchi V. Magnetic Resonance Imaging in Posterior Reversible Encephalopathy Syndrome. Arch Gynecol Obstet 2005;271:79-85.
4. Servillo G. Posterior Reversible Encephalopathy Syndrome in Intensive Care Medicine. Intensive Care Med 2007;33:234-6.
5. Pande AR. Clinicoradiological Factors Influencing the Reversibility of Posterior Reversible Encephalopathy Syndrome. Radiat Med 2006;24:659-68.
6. Sweany J. Recurent Posterior Reversible Encephalopathy Syndrome. Journal of Computer Assisted Tomography 2007;1:148-56.
7. Narbone MC. PRES: Posterior or Potentially Reversible Encephalopathy Syndrome? Neurol Sci 2006;27:187-9.
8. Finister J. Nitroglycerin-Aggravated Pre Eclamptic PRES. Neurology 2003;61:715-6.