Mesial encephalitis: an uncommon presentation of neurosyphilis: a case report and review of the literature

Mimickers of autoimmune encephalitis: a literature review

Autoimmune encephalitis (AIE) is a rapid, progressive neurological disorder characterized by nervous system inflammation. While the Graus criteria are the best known criteria for AIE diagnosis, other differential diagnoses meeting the Graus criteria must be considered before management. This narrative review discusses the most common etiologies that resemble AIE. We suggest routine exclusion of mimickers meeting the Graus criteria before confirming an AIE diagnosis. We reviewed 28 studies including 356 patients. The main initial diagnosis was AIE, then paraneoplastic limbic encephalitis and anti-N-methyl-D-aspartate receptor encephalitis. Only 194 patients met the possible Graus criteria. The most frequent conditions among the total population were dementia, other neurodegenerative diseases, and psychiatric and functional neurological disorders. AIE is often misdiagnosed, leading to unnecessary treatment. Despite publication of the Graus criteria, medical cases mimicking this condition are being published. Many neurological diseases entering the differential diagnosis of AIE could be excluded through a detailed history, neurological examination, laboratory analysis, and other investigations, including cerebrospinal fluid and brain magnetic resonance imaging. However, some differential diagnoses complied with the possible Graus criteria, with some having concurrent antineuronal antibodies, which were considered true mimickers. AIE diagnosis suspicion is primarily clinical, but a definitive diagnosis requires various diagnostic tools.

Neurosyphilis complicated by anti-γ-aminobutyric acid-B receptor encephalitis: A case report

BACKGROUND

Syphilis is an infectious disease caused by Treponema pallidum that can invade the central nervous system, causing encephalitis. Few cases of anti-N-methyl-D-aspartate receptor autoimmune encephalitis (AE) secondary to neurosyphilis have been reported. We report a neurosyphilis patient with anti-γ-aminobutyric acid-B receptor (GABABR) AE.

CASE SUMMARY

A young man in his 30s who presented with acute epileptic status was admitted to a local hospital. He was diagnosed with neurosyphilis, according to serum and cerebrospinal fluid (CSF) tests for syphilis. After 14 d of antiepileptic treatment and anti-Treponema pallidum therapy with penicillin, epilepsy was controlled but serious cognitive impairment, behavioral, and serious psychiatric symptoms were observed. He was then transferred to our hospital. The Mini-Mental State Examination (MMSE) crude test results showed only 2 points. Cranial magnetic resonance imaging revealed significant cerebral atrophy and multiple fluid-attenuated inversion recovery high signals in the white matter surrounding both lateral ventricles, left amygdala and bilateral thalami. Anti-GABABR antibodies were discovered in CSF (1:3.2) and serum (1:100). The patient was diagnosed with neurosyphilis complicated by anti-GABABR AE, and received methylprednisolone and penicillin. Following treatment, his mental symptoms were alleviated. Cognitive impairment was significantly improved, with a MMSE of 8 points. Serum anti-GABABR antibody titer decreased to 1:32. The patient received methylprednisolone and penicillin after discharge. Three months later, the patient's condition was stable, but the serum anti-GABABR antibody titer was 1:100.

CONCLUSION

This patient with neurosyphilis combined with anti-GABABR encephalitis benefited from immunotherapy.

Neurosyphilis presenting as limbic encephalitis

A man in his 50s presented with focal seizures and was found to have an inflammatory cerebrospinal fluid (CSF) with bilateral mesiotemporal lobe hyperintensity on magnetic resonance imaging (MRI) of the brain. Corticosteroid treatment was initiated for management of limbic encephalitis. Focal seizures, imaging abnormalities and inflammatory CSF persisted despite treatment and the patient was found to have neurosyphilis after developing neuropsychiatric symptoms. Syphilis is a sexually transmitted bacterial infection with multisystem involvement including neurological and psychiatric manifestations. Case reports have emerged of neurosyphilis presenting as limbic encephalitis with CSF pleocytosis and temporal lobe hyperintensity on MRI of the brain. Persistence of CSF or MRI abnormalities despite immunosuppressive therapy for limbic encephalitis should prompt investigation for alternate causes of chronic meningoencephalitis, which can occasionally include neurosyphilis.

Neurosyphilis presenting as autoimmune limbic encephalitis: A case report and literature review

RATIONALE

Neurosyphilis presenting as limbic encephalitis (LE) is an important differential diagnosis of autoimmune LE (ALE) defined by Graus in 2016. However, data on the clinical differences and similarities between neurosyphilis presenting as LE and ALE are limited. Herein, we report neurosyphilis presenting as ALE that fulfilled the main items of the Graus ALE criteria. Moreover, a literature review of neurosyphilis presenting as LE was performed.

PATIENT CONCERNS

A 66-year-old Japanese man developed nonconvulsive status epilepticus. He presented with progressive personality change and working memory deficits within 3 months prior to admission. A hyperintense lesion localized in the bilateral medial temporal area was observed on T2-weighted fluid-attenuated inversion recovery brain magnetic resonance imaging. Cerebrospinal fluid analysis showed mild pleocytosis and the presence of oligoclonal band. However, in-house assays did not detect antineuronal antibodies. Electroencephalogram showed lateralized rhythmic delta activity in the right temporal area. The serum and cerebrospinal fluid serological and antigen tests for syphilis had positive results.

DIAGNOSIS

ALE was initially suspected based on the patient's symptoms and ancillary test findings that fulfilled the Graus ALE criteria. However, based on the positive confirmatory test results for syphilis, a diagnosis of neurosyphilis was eventually made.

INTERVENTION

The patient received intravenous midazolam, oral levetiracetam, and lacosamide to control nonconvulsive status epilepticus. In addition, he was treated with intravenous benzylpenicillin at a dose of 24 million units/day for 14 days.

OUTCOMES

The patient's cognitive function relatively improved after antibiotic treatment. However, he presented with persistent mild working memory deficit, which was evaluated with the Wechsler Adult Intelligence Scale, 3rd edition. Therefore, on day 103 of hospitalization, he was transferred to another hospital for rehabilitation and long-term care due to limitations in performing activities of daily living.

LESSONS

The present case was diagnosed with neurosyphilis presenting as ALE, but meanwhile, in most case, neurosyphilis presenting as LE developed at a slower progressive rate, and it had a broader or restricted involvement on brain MRI than ALE based on the literature review. Therefore, an appropriate differential diagnosis of LE can be obtained by identifying clinical differences between the 2 conditions.

Neurosyphilis Mimicking Behavioral Variant of Frontotemporal Dementia in a 59-Year-Old Man

We present the case of a man exhibiting a clinical phenotype of behavioral variant of frontotemporal dementia (bvFTD). The man had developed psychiatric disturbances with verbal aggressiveness over a few months, followed by cognitive and frontal behavioral disorders, fulfilling the clinical criteria for bvFTD. Atrophy and hypometabolism in frontotemporal regions were consistent with the diagnosis. However, serum-screening exams for syphilis infection were positive, and CSF analysis, despite a negative Venereal Disease Research Laboratory Test, suggested the diagnosis of neurosyphilis. After specific antibiotic therapy, the man's behavioral abnormalities and cognitive deficits notably improved, confirming neurosyphilis as the cause of the clinical phenotype. The cognitive deficits completely recovered 1 year post therapy and remained stable for 2 years. After ∼2½ years from the first treatment, the man's behavioral disorders mildly worsened, at which time we re-evaluated him. His cognition was stable, and a positive Venereal Disease Research Laboratory Test confirmed the diagnosis of neurosyphilis. With this case, we demonstrated that in some instances, neurosyphilis can mimic frontotemporal dementia. As a cause of treatable dementia, it should be considered in the differential diagnosis of bvFTD, particularly when psychiatric symptoms and a rapid cognitive decline are noted, even in the presence of brain atrophy and/or hypometabolism.

Neurosyphilis with a rare magnetic resonance imaging pattern confirmed by metagenomic next-generation sequencing: a case report

Background

Neurosyphilis refers to infection of the central nervous system by Treponema pallidum. The clinical presentation is variable and nonspecific. Neuroimaging findings are complex and that the diagnosis is based on clinical presentation, cerebrospinal fluid (CSF) parameters, and serologic and CSF evidence of syphilis. To date, there is no case report describing Treponema pallidum detected by metagenomic next-generation sequencing (mNGS) in CSF.

Case presentation

In this report, we describe a case of neurosyphilis in a HIV-negative, 29-year-old man, who was admitted to our hospital with an epileptic seizure and progressive cognitive impairment. Brain magnetic resonance imaging (MRI) revealed fluid-attenuated inversion recovery (FLAIR) high signal intensities in bilateral medial and anterior temporal lobes, insula, right pulvinar of the thalami, precuneus, frontal and temporo-occipital lobes. Laboratory examination showed positive results by means of nontreponemal or specific treponemal test in serum and CSF. mNGS of the CSF was also performed to identify Treponema pallidum for the first time.

Conclusions

This case underscores the importance of considering neurosyphilis as a potential cause of mesiotemporal abnormality. In addition, the rapid improvement and wide usability of mNGS technology will bring new breakthroughs in the clinical diagnosis of neurosyphilis.

Incidental finding of neurosyphilis with intracranial hemorrhage and cerebral infarction: A case report

Syphilis has recently increased in prevalence in Japan. Neurosyphilis is a special pathological condition of syphilis well known to cause cerebral vasculitis and ischemic stroke. Neurosyphilis in the meningovascular stage rarely causes caliber irregularity of the cerebral blood vessels or cerebral hemorrhage. We describe the case of a 49-year-old Japanese man with neurosyphilis. Cerebral hemorrhage, multiple cerebral infarctions, and caliber irregularity of the cerebral blood vessels were observed, the patient underwent surgery for cerebral hemorrhage on the day of admission, all of which were suspected to be caused by syphilis. He was started on an antibacterial treatment of penicillin on the day of admission and was diagnosed with neurosyphilis the following week based on his serum and spinal fluid test results. His condition improved, and he was transferred to another hospital after 4 weeks of treatment consisting of 3 weeks of infusion treatment with benzylpenicillin followed by oral treatment with amoxicillin. To the best of our knowledge, this is a rare case of neurosyphilis in conjunction with cerebral hemorrhage and cerebral infarction. Clinicians should consider syphilis in the differential diagnosis of cerebral hemorrhage and cerebral infarction and test patients for sexually transmitted diseases, in addition to cerebrospinal fluid testing, when cerebral hemorrhage occurs with an unknown cause. This is especially pertinent when patients present with cerebral infarction or caliber irregularity of the cerebral blood vessels.

Neurosyphilis Mimicking Autoimmune Encephalitis: A Case Report and Review of the Literature

Neurosyphilis may imitate a wide range of neurological and psychiatric diseases, including autoimmune encephalitis. To avoid further cognitive decline and morbidity, early recognition and adequate treatment are of particular importance in both neurosyphilis and autoimmune encephalitis. In case of a strong clinical suspicion of a diagnosis of autoimmune encephalitis, guidelines recommend initiating immunotherapy even in the absence of immunological confirmation. Here, a case of neurosyphilis is reported in which the potential overlap in clinical presentation of autoimmune encephalitis and parenchymatous neurosyphilis is discussed. The here reported data suggest that, in cases presenting with new onset focal epilepsy, slowing of electroencephalographic activity over the temporal regions and magnetic resonance imaging suggestive of swelling of the amygdala, neurosyphilis should be excluded prior to initiation of immunotherapy for suspected autoimmune encephalitis.

Neurosyphilis in the modern era: Literature review and case series

The term of neurosyphilis (NS) refers to infection of central nervous system by Treponema pallidum. Classically, it has been divided into early (meningitis, meningovascular) and late forms (general paresis and tabes dorsalis). The availability of penicillin and high sensitivity of Treponema pallidum to this antibiotic has led to a widely held perception about rarity of syphilitic forms with central nervous system involvement. However, patient can exhibit atypical clinical presentation. Recently different clinical cases with autoimmune encephalitis-mimicking presentation or atypical movement disorders were described. In this article we presented clinical case series with different clinical and MRI presentation and discuss diagnostic and treatment challenges. During our screening period at neurological department we revealed 6 NS cases. Three of them have an atypical presentation. The first patient was misdiagnosed as acute disseminated encephalomyelitis, the second patient had hippocampal sclerosis and epileptic seizures. Another patient had cognitive decline and autoimmune encephalitis-like MRI lesions. We put an emphasis on widening of indication for lumbar puncture and NS tests in patients with syphilitic anamnesis and neurological manifestations.