Charles Bonnet syndrome after herpes simplex encephalitis

Visual impairment associated with Charles Bonnet syndrome is rarely reported in childhood. We describe a child who presented with visual hallucinations and postinfectious bilateral retrobulbar optic neuritis. The patient had undergone acyclovir therapy for 3 weeks because of herpes encephalitis. Four days after therapy was completed, he experienced visual impairment in both eyes. He manifested a bilateral decrease in visual acuity, with normal funduscopic findings. The patient experienced visual hallucinations for about 1 week, and then experienced total loss of vision. During his hallucinations, the patient did not exhibit behavioral changes or cognitive impairment. The visual hallucinations included unfamiliar children hiding under his bed, and he spoke to someone whom he did not know. Magnetic resonance imaging indicated bilateral optic nerve hyperintensity on T(2)-weighted and contrast-enhanced images. The patient received corticosteroid therapy for his retrobulbar optic neuritis, and his vision returned to normal after 1 month. Although rare, visual impairment can be associated with complex visual hallucinations indicative of Charles Bonnet syndrome.     

Herpes simplex encephalitis with herpes simplex retinitis

The association of herpes simplex encephalitis and herpes simplex retinitis is rare in adults. The case presented indicates that the manifestation of retinitis after herpes simplex encephalitis is infectious and not immunologic in origin. Retinal infection results either from neuron-to-neuron transmission of viruses along the optic nerve or from recurrent viral infection. Treatment with acyclovir improves the otherwise rather poor prognosis of combined herpes simplex encephalitis and retinitis. In this case a second course of systemic treatment with acyclovir was effective.     

Diagnosis of herpes simplex encephalitis

In a series of six cases of encephalitis caused by herpes simplex virus, type 1, the diagnostic and prognostic value of the electroencephalogram (EEG) was investigated. Special interest was focused on the time relationship between the appearance of abnormal EEG findings, the initial clinical symptoms and the changes in cranial computed tomography (CT). The characteristic periodic EEG pattern can be demonstrated within 2 days of disease, before typical structural changes appear in CT. A unilateral periodic pattern may be associated with a good prognosis, where-as all patients with bilateral changes died in spite of specific antiviral therapy.     

Update on herpes simplex encephalitis

Herpes simplex encephalitis is the most common identified cause of sporadic viral encephalitis in the United States. Early diagnosis is critical because treatment with the antiviral drug acyclovir dramatically decreases morbidity and mortality. The use of polymerase chain reaction (PCR) techniques to amplify the genome of herpes simplex virus (HSV) from cerebrospinal fluid (CSF) has become the diagnostic procedure of choice. False-positive CSF HSV PCR results are rare when testing is performed in experienced laboratories. Negative CSF HSV PCR results should always be interpreted in the context of the timing of specimen collection and the likelihood of disease. Negative CSF HSV PCR tests can occur within the first 72 hours of illness, with subsequent tests becoming positive. Patients with HSV encephalitis will typically have a negative CSF HSV PCR after 14 days of acyclovir treatment, and a persisting positive PCR should prompt consideration of additional or revised antiviral therapy. Quantitative PCR testing provides information about HSV viral load in CSF, but the potential correlation of viral load with prognosis or other clinical features of disease remains uncertain. Although the neuroimaging abnormalities seen in HSV encephalitis are not unique, more than 90% of patients with proven HSV encephalitis will have magnetic resonance imaging (MRI) abnormalities involving the temporal lobes. Special MRI techniques, including fluid-attenuated inversion recovery and diffusion-weighted imaging, might reveal abnormalities not seen with conventional imaging sequences. Neuroimaging patterns in infants and children differ significantly from those seen in adults and include a higher frequency of extratemporal lesions.     

Relapse of herpes simplex encephalitis

This report describes a child with herpes simplex virus (HSV) encephalitis who improved dramatically while being treated with acyclovir but subsequently had neurological deterioration and died. A severe necrotizing process was present in the brain at autopsy but there were no focal areas of demyelination and poor inflammatory response. HSV was not cultured from brain biopsy during relapse or autopsy. Fourteen previous cases of relapsing herpes encephalitis are reviewed and treatment regime and mechanisms of relapse are discussed.     

Electroencephalography in herpes simplex encephalitis

The EEG in the acute stage of herpes simplex encephalitis (HSE) can show a variety of abnormalities, including uni- or bilateral periodic sharp waves or attenuation of amplitude, focal or generalized slow waves or epileptiform discharges, or electrical seizures. No specific EEG patterns are pathognomonic for HSE, but a focal or lateralized EEG abnormality in the presence of encephalitis is highly suspicious of HSE. In the acute stage, EEG appears to be more sensitive than computerized tomography or radioisotope brain scanning. The EEG findings tend to differ in the course of illness, and the periodic discharges occur only during the acute stage. The EEG findings in either the acute stage or long-term follow-up do not predict the chance of survival or severity of disability, and EEG changes appear to lag behind the clinical changes. EEG results can become normal in both adults and neonates when the acute stage is over.     

Murray valley encephalitis mimicking herpes simplex encephalitis.

We describe a patient with serologically proven Murray Valley encephalitis (MVE), whose presentation was clinically and radiologically characteristic of Herpes simplex encephalitis (HSE). The reports of MRI abnormalities in MVE, and the closely related Japanese Encephalitis and West Nile virusii are mostly of bilateral thalamic or grey matter involvement. The MRI scan findings in this case instead showed the typical temporal lobe changes of HSE. Our case report highlights that MVE can mimic HSE, both clinically and radiologically. Therefore it is important to collect an accurate and detailed travel history from patients where there is a risk of exposure to MVE virus. If suspected, antibody testing of serum and CSF, and CSF for MVE-RNA if available, should be undertaken. This case also highlights the potential under-diagnosis of Murray Valley encephalitis.     

LaCrosse viral encephalitis mimics herpes simplex viral encephalitis

Temporal lobe abnormalities, findings commonly associated with herpes simplex virus encephalitis, were observed in a male 10 years of age found to have LaCrosse virus encephalitis. Diagnostic features included magnetic resonance imaging revealing abnormal signal intensity in the bilateral frontotemporal regions, and left-sided periodic lateralizing epileptiform discharges. LaCrosse virus encephalitis should be included in the differential diagnosis of viral encephalitis associated with structural and electrographic temporal lobe lesions, represented by periodic lateralizing epileptiform discharges. The recently developed LaCrosse RNA polymerase chain reaction for cerebrospinal fluid may enable rapid diagnosis, prevent the need for treatment with acyclovir, and give parents an encouraging prognosis.     

Acyclovir resistance in herpes simplex encephalitis

Herpes simplex virus type 1 is a common cause of severe sporadic encephalitis. Treatment with acyclovir is highly effective in this disease. We report the case of a 27‐year‐old, immunocompetent woman with acyclovir‐resistant herpes simplex encephalitis. Although she had not been treated before, herpes simplex virus type 1 DNA from the cerebrospinal fluid showed a non‐synonymous mutation in the thymidine kinase gene, which is likely to have caused resistance to acyclovir. Herpes simplex encephalitis resolved after treatment with foscarnet. To our knowledge, this is the first report of acyclovir‐resistant herpes simplex virus encephalitis in an immunocompetent, previously therapy‐naive adult. ANN NEUROL 2010;67:830–833     

单纯疱疹病毒脑炎的临床研究

目的 从临床特点、脑脊液（CSF）特异性抗体检测、神经影像学和治疗等方面对单纯疱疹病毒脑炎（HSE）进行分析，以期加深对本病的认识，提高早期诊断水平和治愈率。方法 在96例病毒性脑炎患者中确诊25例成人HSE病例，并对其临床表现、CT和／或MRI结果、实验室检查、治疗及预后进行分析。结果 HSE呈急性或亚急性起病，本组发病年龄中位数为35岁。主要早期表现为发热、头痛、意识和行为人格改变。神经影像学检查有助于诊断。CSF单纯疱疹病毒特异性抗体水平明显升高。意识障碍程度及无环鸟苷的及时应用与预后有关。结论 HSD最具特征的早期临床表现为意识障碍和行为人格改变。CT检查不能用于早期诊断。发病1周CT检查正常时，MRI能发现局灶性病变。CSF单纯疱疹病毒特异性抗体水平的升高是重要的诊断依据。无环鸟苷的早期使用是改善预后的关键。     

Intracerebral hematoma complicating herpes simplex encephalitis

Objectives

To describe two patients who developed an intracranial hematoma as a complication of temporal lobe encephalitis due to herpes simplex type 1 virus, and to review the literature.

Patients and methods

The first patient, a 45-year-old woman developed a brain hematoma in the location of the encephalitic lesion on day 9 after the onset of herpes simplex encephalitis (HSE) that required surgical evacuation. The second patient, a 53-year-old woman was being treated for HSE; on day 8 after admission a temporal lobe hematoma with midline shift was disclosed due to persistent headache. Both patients survived but were left with sequelae. We conducted a PubMed/MEDLINE search from 1986 to April 2013 on this topic.

Results

We have found 20 additional cases reported in the literature and review their characteristics. Hemorrhage was present on admission in 35% of pooled patients, and consistently involved the area of encephalitis. Clinical presentation of intracranial hemorrhage overlapped the encephalitic symptoms in two-thirds of the patients. Half of patients underwent surgery. Overall, mortality rate was low (5.2%), and half of patients fully recovered.

Conclusions

Intracranial bleeding, although infrequent, can complicate the evolution of herpes simplex encephalitis and should be borne in mind since its presence may require neurosurgery. Although its presentation may overlap the encephalitic features, the lack of improvement or the worsening of initial symptoms, particularly during the second week of admission, should lead to this suspicion and to perform a neuroimaging study.