Postencephalitic chronic granulomatous disease

A rare suspected case of chronic nodular granulomatous herpes simplex encephalitis in an adult

Herpes simplex encephalitis is the most common sporadic viral encephalitis in the western world, HSV-1 (herpes simplex virus) being the mostly commonly implicated serotype. The disease is usually monophasic, although patients may relapse weeks, months or years after initial infection. This chronic granulomatous inflammatory process is almost exclusively described in children and rarely forms discrete enhancing parenchymal nodules. We present the clinical and radiological features of an unusual case of chronic nodular granulomatous herpes encephalitis with enhancing “mass-like” nodules in an adult. To the author’s knowledge, this is the first reported case of macroscopic “mass-like” nodular granuloma formation in an adult.

Epilepsy surgery for epileptic encephalopathy as a sequela of herpes simplex encephalitis: case report

Herpes simplex virus (HSV) encephalitis can manifest with different clinical presentations, including acute monophasic illness and biphasic chronic granulomatous HSV encephalitis. Chronic encephalitis is much less common, and very rare late relapses are associated with intractable epilepsy and progressive neurological deficits with or without evidence of HSV in the cerebrospinal fluid. The authors report on an 8-year-old girl with a history of treated HSV-1 encephalitis when she was 13 months of age and focal epilepsy when she was 2 years old. Although free of clinical seizures, when she was 5, she experienced behavioral and academic dysfunction, which was later attributed to electrographic focal seizures and worsening electroencephalography (EEG) findings with electrical status epilepticus during slow-wave sleep (ESES). Following a right temporal lobectomy, chronic granulomatous encephalitis was diagnosed. The patient's clinical course improved with the resolution of seizures and EEG abnormalities.

Granulomatous herpes simplex encephalitis in an infant with multicystic encephalopathy: a distinct clinicopathologic entity?

BACKGROUND

Herpes simplex virus encephalitis can manifest as a range of clinical presentations including classic adult, neonatal, and biphasic chronic-granulomatous herpes encephalitis.

METHOD

We report an infant with granulomatous herpes simplex virus type 2 encephalitis with a subacute course and multicystic encephalopathy.

CASE

A 2-month-old girl presented with lethargy and hypothermia. Computed tomography scan of the head showed multicystic encephalopathy and calcifications. Cerebrospinal fluid analysis by polymerase chain reaction testing for herpes simplex virus 1 and 2, enterovirus, and cytomegalovirus was negative. Normal cerebrospinal fluid interferon-α levels argued against Aicardi-Goutières syndrome. The patient died 2 weeks after presentation. At autopsy, multicystic encephalopathy was confirmed with bilateral gliosis, granulomatous inflammation with multinucleated giant cells, and calcifications. Bilateral healing necrotizing retinitis suggested a viral etiology, but retina and brain were free of viral inclusions and immunohistochemically negative for herpes simplex virus-2 and cytomegalovirus. However, polymerase chain reaction analysis showed herpes simplex virus-2 DNA in four cerebral paraffin blocks. Subsequent repeat testing of the initial cerebrospinal fluid sample using a different polymerase chain reaction assay was weakly positive for herpes simplex virus-2 DNA.

CONCLUSION

Granulomatous herpes simplex virus encephalitis in infants can present with subacute course and result in multicystic encephalopathy with mineralization and minimal cerebrospinal fluid herpes simplex virus DNA load. Infectious etiologies should be carefully investigated in the differential diagnosis of multicystic encephalopathy with mineralization, in particular if multinucleated giant cells are present.

Chronic granulomatous herpes encephalitis: a rare entity posing a diagnostic challenge

Herpesviruses can cause an acute, subacute, or chronic disease state in both immunocompetent and immunocompromised individuals. Herpes simplex virus (HSV) encephalitis is most often an acute monophasic disease process. Rarely, however, it may progress to a chronic state, and more rarely still to a granulomatous encephalitis. Prior studies have suggested that antiviral immunity with Toll-like receptors determines susceptibility to herpesviruses. The authors report the case of a 14-year-old girl with a remote history of treated HSV encephalitis, who had intractable seizures and worsening MR imaging changes that were concerning for either a neoplastic or an inflammatory process. She was found to have granulomatous herpes simplex encephalitis and had a low cytokine response to Toll-like receptor 3 stimulation.

La crosse virus encephalitis preceding neurosarcoidosis diagnosed by brain biopsy

Childhood neurosarcoidosis is rare, and its etiology is unknown. La Crosse virus is one of the most common causes of encephalitis in North America. We report the case of a 12-year-old boy who had La Crosse virus encephalitis and subsequently developed imaging and pathologic findings suggestive of neurosarcoidosis. He presented with acute onset of transient aphasia 4 months after an episode of encephalitis; serology results at the time of aphasia were positive for La Crosse virus. Brain MRI revealed diffuse subcortical nodular lesions. His serum angiotensin-converting enzyme level was elevated, and brain biopsy revealed noncaseating granuloma. It is interesting to note that he has had no recurrence of aphasia; repeat MRI showed significant improvement of nodular lesions without therapy. To our knowledge, this is the first case of La Crosse virus encephalitis associated with neurosarcoid findings.

Chronic active herpes simplex type 2 encephalitis in an asymptomatic immunocompetent child

A unique form of chronic, active, granulomatous herpes simplex type 2 encephalitis is described in an asymptomatic, immunocompetent 8-year-old girl who acquired the virus as a neonate. The extensive, bilateral cerebral parenchymal involvement was discovered incidentally. Diagnosis was confirmed by a combination of serial neuroimaging, brain biopsy, and quantitative polymerase chain reaction targeted to DNA sequences in the glycoprotein G gene, allowing differentiation between herpes simplex virus types 1 and 2. The clinical course over a 5-year period, treatment with intermittent intravenous steroids, and daily valacyclovir, diagnostic imaging, and laboratory studies are reviewed in detail. This form of herpes simplex virus type 2 encephalitis hasn't been described previously and is significant because of its prolonged indolent course, absence of neurological findings or suggestive history, and benign behavior in this child, who is now 14 years old. The authors believe this entity can be unsuspected and underdiagnosed in the general pediatric population, especially in those with a prior maternal history of herpes simplex virus type 2 infection.

Asymptomatic self-limiting diffuse white matter lesions in subacute to chronic stage of herpes simplex encephalitis

This study evaluated white matter changes in the subacute and chronic stages of herpes simplex encephalitis (HSE). Subjects comprised 15 patients with HSE. All patients were examined using MRI at onset, and then at seven to ten days, three to five weeks and two to three months after onset. In addition, the six patients who displayed white matter signal abnormalities were examined at six months and <one year after onset. Cell count, protein levels, polymerase chain reaction (PCR) of herpes simplex virus in cerebrospinal fluid (CSF), and exacerbation of neurological symptoms as well as dose of acyclovir were compared between patients with and without white matter abnormalities. Diffuse white matter signal changes were identified at the subacute stage (3-5 weeks after onset) of HSE in six patients (6/15, 40%). No significant relationship was observed between the presence of white matter signal abnormalities and laboratory data, acyclovir dose or clinical symptoms. These signal abnormalities disappeared or improved by two years without any clinical treatment. Diffuse white matter signal abnormalities occur frequently in the subacute stage of HSE. Although the mechanisms underlying these white matter lesions have not been elucidated, subclinical immune-mediated processes may be considered. Repeat MRI studies over a long period are necessary for evaluating the clinical process of patients with HSE.

The spectrum of herpes simplex encephalitis in children

Clinical and basic science research carried out in recent years into herpes simplex encephalitis (HSE) have shown that the concept of a "classical" picture of HSE in children is now outdated and that our current knowledge of the disease is probably only the tip of an iceberg. Indeed, increasing evidence supports the existence of a wider range of pathophysiological mechanisms, clinical presentations and disease progressions in paediatric HSE. This paper reviews the clinical, biological and radiological data available and redefines the spectrum of HSE in children. Full understanding of the condition should improve the management of suspected cases and decrease the morbidity and the mortality associated with this disease.