Herpes Simplex Viral Encephalitis Masquerading as a Classic Left MCA Stroke

Abstract

Objective. Stroke is a clinical diagnosis, with a history and physical examination significant for acute onset focal neurological symptoms and signs, often occurring in patients with known vascular risk factors and is frequently confirmed radiographically. Case Report. A 79-year-old right-handed woman, with a past medical history of hypertension, hyperlipidemia, and prior transient ischemic attack (TIA), presented with acute onset global aphasia and right hemiparesis, in the absence of fever or prodrome. This was initially diagnosed as a proximal left middle cerebral artery (MCA) stroke. However, CT perfusion failed to show evidence of reduced blood volume, and CT angiogram did not show evidence of a proximal vessel occlusion. Furthermore, MRI brain did not demonstrate any areas of restricted diffusion. EEG demonstrated left temporal periodic lateralized epileptiform discharges (PLEDs). The patient was empirically loaded with a bolus valproic acid and started on acyclovir, both intravenously. CSF examination demonstrated a pleocytosis and PCR confirmed the diagnosis of herpes simplex viral encephalitis (HSVE). Conclusions. HSVE classically presents in a nonspecific fashion with fever, headache, and altered mental status. However, acute focal neurological signs, mimicking stroke, are possible. A high degree of suspicion is required to institute appropriate therapy and decrease morbidity and mortality associated with HSVE.

Herpes Simplex Virus Encephalitis: Atypical Presentation as a Right Middle Cerebral Artery Stroke

“…Because of this, EEG can play a significant role in the diagnosis as well as the progression of HSVE [ 3 ]. In a separate retrospective study, EEG was able to localize HSVE earlier in around 80% of patients [ 9 ]. Abdelmalik, et al have reported the case of an elderly lady who presented with acute onset global aphasia and right hemiparesis in the absence of a prodromal phase, initially diagnosed as a proximal left middle cerebral artery (MCA) stroke.…”

Herpes encephalitis : a stroke mimicker

“…Since early imaging can be normal in acute stroke, as was in this patient, tPA was administered. The patient who presented with MCA stroke features as reported in the case report above did not receive tPA since it was outside the 3-hour window but was admitted to an acute stroke unit for close monitoring [5]. The MRI at 24 hours after admission in the patient we reported showed an increased FLAIR and T2 signal hyperintensity within the medial left temporal lobe with slight effacement of the cysts sulci which was concerning for encephalitis.…”

“…Timely recognition and treatment can alter the mortality of HSVE from 70% to 14-30% [5,7]. Our patient responded well to the acyclovir which was started a day after admission, and he had a complete recovery in 6 weeks.…”

“…She had prodromal symptoms of headache, nausea, vomiting, and fatigue the day prior to the presentation [4]. On admission her temperature was mildly elevated at 100.2 F. In the 2nd report, the patient presented with symptoms suggestive of a typical MCA stroke of global aphasia, left gaze deviation and right-sided hemiparesis [5]. This patient developed a fever of 101.4 F, 11 hours after admission.…”

“…Our patient responded well to the acyclovir which was started a day after admission, and he had a complete recovery in 6 weeks. Poor outcomes have been noted with Acyclovir therapy if started 2 days after admission [5]. However, even in patients who receive prompt treatment, neurocognitive deficits can last long term.…”