Diagnostic delay in a case of herpes simplex encephalitis

Abstract

Herpes simplex encephalitis (HSE) is the most frequent cause of sporadic fatal encephalitis in the Western world. Definitive diagnosis by viral PCR of cerebrospinal fluid (CSF) and treatment with aciclovir have improved the prognosis significantly. Nevertheless, the condition is rare and presents with non-specific symptoms that can easily be mistaken for systemic infection or non-infective encephalopathy. We report a case of HSE which was not recognised by four separate doctors, leading to substantial delay in diagnosis and treatment. Our patient presented with fever, headaches, altered behaviour and generalised bradykinesia. This was initially diagnosed as otitis interna (labyrinthitis) and, subsequently, an ischaemic stroke. There was a delay of 10 days in the initiation of aciclovir from symptom onset. MRI and CSF PCR confirmed herpes simplex virus type-1 (HSV-1) infection. The patient improved on aciclovir, but is disabled with word-finding difficulties and cognitive slowing.

Figure 1

CT scan of the head. Transverse section at the level of the orbits. Note the region of hypodensity in the right frontal, parietal and temporal lobes, as well as the mega cisterna magna, a feature of this patient’s excised cranial meningocoele.

Figure 2

T2-weighted MRI scans of the head. (A) Transverse section at the level of the optic chiasm demonstrating high signal in both white and grey matter of the right frontal, parietal and temporal lobes. (B) Coronal section, showing mass effect with compression of the right lateral ventricle.