Fatal PCR-negative herpes simplex virus-1 encephalitis with GABAA receptor antibodies

Anti-γ-aminobutyric acid-A receptor encephalitis with refractory seizures and cognitive impairment in a young woman: A case report

Anti-γ-aminobutyric acid-A receptor (GABAAR) encephalitis is an underappreciated cause of autoimmune encephalitis and remains refractory to antiepileptic therapies unless autoimmune responses are addressed. Herein, we reported a case of anti-GABAAR encephalitis in a young woman. A 29-year-old woman was admitted because of seizures for 10 months, memory decline for 7 months, and paroxysmal limbs jerking for 5 months. At admission, the patient showed mild cognitive impairment. Cell-based assays found no antibodies associated with common autoimmune encephalitis in the cerebrospinal fluid (CSF) and no antibodies in the plasma and CSF against central nervous system demyelination-associated proteins. MRI revealed multiple cortical-subcortical abnormalities and electroencephalography demonstrated periodic epileptiform discharges during paroxysmal clonus. A second test 1 month after admission detected antibodies against GABAAR α1/β3/γ2 in the plasma and CSF, leading to a diagnosis of anti-GABAAR encephalitis. The patient received intravenous immunoglobulin, prednisone, azathioprine, and levetiracetam and recovered from limb jerks and was no longer amnesic. A second episode occurred after an apparent cold and was managed by intravenous immunoglobulin, cyclophosphamide, and methylprednisolone with subsequent prednisone and levetiracetam. The patient was able to speak and ambulate after 15 days of treatment. Her MMSE, MoCA, and MRS scores improved. Physicians should harbor a high index of suspicion of anti-GABAAR encephalitis in refractory encephalitis patients with the manifestation of seizures or psychiatric disorders. Tests for a comprehensive panel of antibodies associated with anti-GABAAR encephalitis should be carried out in suspected cases and immunotherapy should be promptly initiated upon diagnosis to prevent irreversible neurological damage.

An Enigmatic Case of a Febrile Infant With Seizures

Herpes simplex virus (HSV) encephalitis is one of the most common viral infections in infants associated with high morbidity and mortality rates despite available antiviral therapy. For symptomatic infants, starting empiric therapy with acyclovir can prevent serious neurological sequelae while awaiting results from diagnostic studies. The gold standard of diagnosis remains to be the detection of HSV DNA via polymerase chain reaction (PCR) from cerebrospinal fluid (CSF). However, due to the low viral load in the initial stages of infection, even the gold standard test may not detect active infection. We present a case of an eight-month-old child who presented with fever and seizures and had negative HSV DNA PCR from initial CSF studies. Ongoing fever and recurrent seizures prompted an MRI which was suggestive of meningoencephalitis, HSV DNA PCR from repeat CSF sample resulted positive. This case emphasizes the importance of keen clinical judgment and the caution required when deciding to stop empiric therapy when the clinical suspicion for HSV encephalitis remains high.

Caspr2 antibodies in herpes simplex encephalitis: an extension of the spectrum of virus induced autoimmunity? - A case report

BACKGROUND

Post herpes simplex virus (HSV) autoimmune encephalitis has been reported mainly in association with NMDA receptor antibodies, however, never with Caspr2 antibodies.

CASE PRESENTATION

We report an 82-year old female patient with encephalitis who presented with aphasia, left temporo-mesial hyperintense lesion on MRI, epileptiform discharges on spot electroencephalography, cerebrospinal fluid (CSF) lymphocytic pleocytosis and who showed positive HSV polymerase chain reaction in CSF as well as antibodies against contactin-associated protein-like 2 (Caspr2).

CONCLUSION

This is the first report of a patient with encephalitis who tested positive for HSV as well as for Caspr2 antibodies.

Relapse of Herpes Simplex Encephalitis by Epilepsy Surgery 35 Years after the First Infection: A Case Report and Literature Review

Late relapse of herpes simplex encephalitis (HSE) is defined as the recurrence of HSE more than 3 months after the initial exposure. The postoperative diagnosis of HSE following neurosurgery is complicated because the clinical presentation can mimic other common complications of neurosurgery. Cerebrospinal fluid polymerase chain reactions (CSF-PCR) is the gold standard for the diagnosis of HSE. We describe a case of late HSE relapse after epilepsy surgery in a patient who required a brain biopsy due to repeated negative CSF-PCR results. A 38-year-old woman had a history of HSE from the age of 3 years. She had intractable epilepsy from the age of 20 years and underwent right posterior quadrant disconnection (PQD) at the age of 38 years. Postoperatively, she had a right hemispheric intracerebral hemorrhage (ICH) and her consciousness was gradually worsening. Her consciousness improved after removal of the ICH. However, her consciousness gradually deteriorated again. Fluid-attenuated inversion recovery (FLAIR) revealed bilateral hyperintensity in the frontal lobes, including the white matter. CSF-PCR for herpes simplex virus (HSV) was performed twice, but yielded negative results. We performed a brain biopsy to target FLAIR hyperintensity in the right frontal lobe. PCR of the brain specimen was positive for HSV. Her consciousness improved with acyclovir, methylprednisolone, and cyclophosphamide. To our knowledge, this is a case of HSE induced by epilepsy surgery which had the longest duration until relapse after the initial HSE episode. A brain biopsy can be used to confirm the diagnosis of suspected HSE when CSF-PCR results are negative.

Polymerase Chain Reaction (PCR)-Negative Herpes Simplex Virus (HSV) Encephalitis in a 62-Year-Old Woman With p-ANCA Vasculitis

We present the case of a 62-year-old woman with a past medical history significant for p-ANCA vasculitis (on immunosuppression) who was found to have polymerase chain reaction (PCR)-negative herpes simplex virus (HSV) encephalitis. We also present a review of all identifiable reports of PCR-negative HSV encephalitis in the past 20 years. To our knowledge, this is the first case of PCR-negative HSV encephalitis in a patient with p-ANCA vasculitis and the thirteenth overall in this timeframe. The patient presented with new-onset fever, encephalopathy, and a first-in-lifetime focal motor seizure progressing to status epilepticus. Cerebrospinal fluid (CSF) PCR was negative for HSV on three separate instances between the first and thirteenth days since symptom onset, and the CSF profile was not typical for HSV encephalitis. The patient underwent a brain biopsy, which confirmed the presence of HSV. She continued to worsen despite aggressive seizure control and six days of empiric acyclovir. Unfortunately, she expired despite the reinitiation of acyclovir. When faced with the classical features of encephalitis in the immunocompromised, the suspicion of HSV should remain high despite negative PCR results. The completion of a full course of acyclovir in the absence of clinical improvement should be considered.

Cross-reactivity of a pathogenic autoantibody to a tumor antigen in GABAA receptor encephalitis

Encephalitis associated with antibodies against the neuronal gamma-aminobutyric acid A receptor (GABA_A-R) is a rare form of autoimmune encephalitis. The pathogenesis is still unknown but autoimmune mechanisms were surmised. Here we identified a strongly expanded B cell clone in the cerebrospinal fluid of a patient with GABA_A-R encephalitis. We expressed the antibody produced by it and showed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry that it recognizes the GABA_A-R. Patch-clamp recordings revealed that it tones down inhibitory synaptic transmission and causes increased excitability of hippocampal CA1 pyramidal neurons. Thus, the antibody likely contributed to clinical disease symptoms. Hybridization to a protein array revealed the cross-reactive protein LIM-domain-only protein 5 (LMO5), which is related to cell-cycle regulation and tumor growth. We confirmed LMO5 recognition by immunoprecipitation and ELISA and showed that cerebrospinal fluid samples from two other patients with GABA_A-R encephalitis also recognized LMO5. This suggests that cross-reactivity between GABA_A-R and LMO5 is frequent in GABA_A-R encephalitis and supports the hypothesis of a paraneoplastic etiology.

Anti-gamma-aminobutyric acid receptor type A encephalitis: a review

PURPOSE OF REVIEW

To systematically review the clinical features, diagnosis, and management of anti-gamma-aminobutyric acid receptor Type A (GABAA) autoimmune encephalitis with a focus on recent data.

RECENT FINDINGS

In a review of published reports, we identified 50 cases of anti-GABAA receptor encephalitis with clinical features reported. The median age at presentation was 47 years old (range, 2.5 months-88 years old), 64% were adults, 36% were children and it occurred in both males and females. Eight-two percent (41/50) presented with seizures, 72% (36/50) with encephalopathy, and 58% (29/50) with both. Of those presenting with seizures, 42% developed status epilepticus during their disease course. Ninety-six percent (48/50) had MRI results reported, with 83% of these cases having abnormal findings, most commonly multifocal/diffuse cortical and subcortical T2/FLAIR hyperintense lesions without associated gadolinium enhancement. Almost one-third, 28% (14/50), had an associated malignancy detected by the time of diagnosis, 64% (9/14) of which was thymoma. Of 44 patients with outcomes reported, 80% had partial or complete recovery, whereas 20% had poor outcomes including 11% (5/44) who died. Of the 42 patients with type of treatment(s) and outcomes reported, 54% (23/42) received only first-line immunotherapy and 31% (13/42) received first-line and second-line immunotherapy. Receiving a combination of first-line and second-line immunotherapy may be associated with higher likelihood of complete recovery. When follow-up MRIs were reported, all showed improvement, and sometimes complete resolution, of T2/FLAIR hyperintensities.

SUMMARY

Anti-GABAA receptor encephalitis can present across the age spectrum and should be considered in patients who present with rapidly progressive encephalopathy and/or seizures. Brain MRI often shows a distinctive pattern of multifocal cortical and subcortical T2/FLAIR hyperintense lesions, generally not typical of other known central nervous system autoantibody associated encephalitis syndromes. High clinical suspicion and early diagnosis are important given the potential for clinical improvement with immunotherapy.