Neurosyphilis with mesiotemporal magnetic resonance imaging abnormalities

Alzheimer's Disease and Neurosyphilis: Meaningful Commonalities and Differences of Clinical Phenotype and Pathophysiological Biomarkers

BACKGROUND

Neurosyphilis-associated cognitive and behavioral impairment- historically coined as "general paralysis of the insane"- share clinical and neuroradiological features with the neurodegenerative disease spectrum, in particular Alzheimer's disease (AD). Anatomopathological similarities have been extensively documented, i.e., neuronal loss, fibrillary alterations, and local amyloid-β deposition. Consequently, accurate classification and timely differential diagnosis may be challenging.

OBJECTIVE

To describe clinical, bio-humoral, brain MRI, FDG-PET, and amyloid-PET features in cases of neurosyphilis with an AD-like phenotypical presentation, as well as clinical outcome in terms of response to antibiotic therapy.

METHODS

We selected the studies comparing patients with AD and with neurosyphilis associated cognitive impairment, to investigate candidate biomarkers classifying the two neurological diseases.

RESULTS

The neuropsychological phenotype of general paralysis, characterized by episodic memory impairment and executive disfunction, substantially mimics clinical AD features. Neuroimaging often shows diffuse or medial temporal cortical atrophy, thus contributing to a high rate of misdiagnosis. Cerebrospinal fluid (CSF)-based analysis may provide supportive diagnostic value, since increased proteins or cells are often found in neurosyphilis, while published data on pathophysiological AD candidate biomarkers are controversial. Finally, psychometric testing using cross-domain cognitive tests, may highlight a wider range of compromised functions in neurosyphilis, involving language, attention, executive function, and spatial ability, which are atypical for AD.

CONCLUSION

Neurosyphilis should be considered a potential etiological differential diagnosis of cognitive impairment whenever imaging, neuropsychological or CSF features are atypical for AD, in order to promptly start antibiotic therapy and delay or halt cognitive decline and disease progression.

Neurosyphilis in disguise

PURPOSE

Neurosyphilis can mimic different diseases, not only in its clinical presentation but also on imaging. Treponema pallidum is also known as the "great imitator." Having an ultimate diagnosis of neurosyphilis is quite critical as this can affect management drastically. Herein, we discuss the case of a 69-year-old female who was treated for neurosyphilis, while having an atypical imaging finding of anterior temporal lobe enhancement that simulated an infection with herpes simplex virus (HSV); we also review the available literature on different imaging findings in both the early and late stages of the disease.

METHODS

We performed a literature search using the new PubMed in June 2021. The terms "neurosyphilis", "MRI", and "neuroimaging" were used either alone or in combination with "early neurosyphilis" or "late neurosyphilis". Data on neurosyphilis and imaging findings was mainly derived from review articles, cohort studies, case series, and individual reports.

CONCLUSION

Neurosyphilis can present with an extensive variation and different patterns on the MRI, and clinicians must be aware of the wide variety in radiological presentations. Anterior temporal lobe involvement is a rare presentation and requires evaluating for neurosyphilis to prevent a missed diagnosis and treatment.

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 Mimicking Creutzfeldt-Jakob Disease

Background

As rapidly progressive dementia (RPD), general paresis and Creutzfeldt-Jakob disease (CJD) may have overlapping clinical presentation due to a wide variety of clinical manifestations.

Case Report

A 57-year-old man presented with rapid progressive cognitive decline, behavioral change, ataxic gait, tremor and pyramidal signs for 3 months. In addition to these multiple systemic involvements, positive result for the cerebrospinal fluid (CSF) 14-3-3 protein tentatively diagnosed him as probable CJD. However, due to increased serum rapid plasma reagin, venereal disease research laboratory, and fluorescent treponemal antibody-absorption reactivity in CSF, the final diagnosis was changed to general paresis.

Conclusions

A patient with RPD needs to be carefully considered for differential diagnosis, among a long list of diseases. It is important to rule out CJD, which is the most frequent in RPD and is a fatal disease with no cure. Diagnostic criteria or marker of CJD, such as 14-3-3 protein, may be inconclusive, and a typical pattern in diffusion-weighted imaging is important to rule out other reversible diseases.

Neurocognitive changes in tertiary neurosyphilis: a retrospective chart review

CONTEXT

Since the beginning of the new millennium, prevalence of syphilis has re-increased and is once again, a major public health problem. Neurosyphilis is the extension of syphilitic infection to the nervous system. It is considered by many as a cause of reversible dementia, when treated early. However, scarce data exist on the evolution of cognitive and behavioral impairments in patients affected by tertiary neurosyphilis.

OBJECTIVES

The aim of this study was to explore the cognitive and behavioral changes in a cohort of patients diagnosed with neurosyphilis.

DESIGN

A retrospective study based on systematized chart review between 2000 and 2012 in a large neurological tertiary care facility.

OUTCOME MEASURE

Clinical evaluations by treating physicians.

RESULTS

Eighteen patients were identified with tertiary neurosyphilis. Out of this group, only two had systematic neuropsychological follow-up despite physician reports of significant and persistent cognitive and psychiatric changes. For these two cases, only slight improvements were noted in memory and executive skills while improvements in attention were marked. None of our patients had previous psychiatric history yet a large proportion developed symptoms after the infection.

CONCLUSION

Although neurosyphilis is traditionally considered a reversible form of dementia, we found limited support for this claim in our two patients with close follow-up. Quality data on the cognitive and psychiatric changes in the rest of our cohort was dramatically lacking, and this could not be explained by absence of symptoms at presentation. Given the recrudescence of syphilis, we propose a systematic approach to the evaluation and follow-up of this disorder.

Anti-NMDAR encephalitis and other glutamate and GABA receptor antibody encephalopathies

Over the last few year, antibodies to various central nervous system receptors, particularly the glutamate and γ-aminobutyric acid (GABA) receptors, have been found to be associated with autoimmune neurologic disorders. The receptors include the N-methyl-d-aspartate receptor (NMDAR), the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), the metabotropic glutamate receptors (mGluRs), and GABA type A and B receptors (respectively GABAAR and GABABR). Compared to the previously described paraneoplastic antibodies directed at intracellular targets, the patients with receptor antibodies are often younger, they less frequently have malignancies, and they respond better to immunotherapy. Many of the patients have limbic encephalitis with amnesia, disorientation, seizures, and psychological or psychiatric symptoms, but those with NMDAR antibodies usually develop a more widespread form of encephalitis, often leading to a decrease in consciousness and requirement for long-term intensive care treatment. The autoantibodies bind directly to the synaptic or extrasynaptic receptors on the membrane surface, and have direct effects on signal transduction in central synapses. These conditions are very important to recognize as the symptoms and complications can be fatal when not treated in time, whereas with immunotherapy many patients recover considerably.

Mesiotemporal changes on magnetic resonance imaging in neurosyphilis

We report a case of neurosyphilis with magnetic resonance imaging (MRI) brain scan findings compatible with a diagnosis of herpes simplex encephalitis with negative testing for herpes simplex virus in the cerebral spinal fluid. An extensive review of the literature has been undertaken revealing 24 cases worldwide where there are mesiotemporal changes on MRI concurrent with a diagnosis of neurosyphilis. Therefore, it is now well established that neurosyphilis, 'the great imitator', should be considered in the differential diagnosis in all patients demonstrating mesiotemporal changes on MRI, changes usually seen in herpes simplex encephalitis.

MRI findings and early diagnosis of general paresis of the insane

The objective of this study was to improve the knowledge of the clinical and MRI presentation of general paresis of the insane (GPI) and achieve its early diagnosis. Fifteen patients with GPI were gathered. Their clinical data and brain MRI information were analyzed. The age range was 33-62 years (mean: 48·8 years). The disease lasted 34 days-28 months (mean: 10·87 months). Treponema pallidum hemagglutination assays (TPHAs) on the cerebrospinal fluid (CSF) and sera were positive. All patients were human immunodeficiency virus (HIV) negative and primarily showed progressive cognitive impairment, mostly accompanied with emotional disturbance and psychosis. The accompanying symptoms included epilepsy (n  =  7), ataxia (n  =  5), cerebral vascular disease (n  =  3), and limbs tremor (n  =  2). Typical Argyll Robertson's pupil was observed in two cases. A CSF examination showed elevated white blood cell (WBC) and protein level. Purely cerebral atrophy was found in three cases. Abnormal high signals were found in nine cases in different brain area, mainly in bilateral temporal, insular, and frontal lobes and hippocampus in T2-weighted and fluid-attenuated inversion recovery (FLAIR), which was accompanied by cerebral and/or hippocampus atrophy. Purely atrophy of bilateral or unilateral hippocampus was found in two cases. Cerebral infarction lesions were found in three cases. Contrary to the previous reports, the hippocampal atrophy and bilateral abnormal signals of hippocampus and temporal lobe in brain MRI were more common in cases with GPI. Abnormal signals were probably related to proliferation of glial cells rather than cytotoxic edema. The pathogenesis of the abnormal signals needs to be further explored. General paresis of the insane has a wide variety of central nervous system manifestations, either clinically or neuroradiologically. Identification of these presentations could be important for early diagnosis.

What should you know about limbic encephalitis?

Autoimmune encephalitis is an inflammatory disorder characterized by a subacute impairment of short-term memory, psychiatric features and seizures. It is often associated with a variety of other neurological symptoms, and its differential diagnosis is wide, leading to challenges in its recognition. It used to be regarded as a rare disease, usually paraneoplastic and with poor prognosis. However, with the recent recognition of membrane-surface directed antibodies, it is now known that in a substantial proportion of cases there is no association with any malignancy and there is a good prognosis if treated. Hence, early recognition and prompt initiation of immunotherapies are of great importance.

Neurosyphilis with dementia and bilateral hippocampal atrophy on brain magnetic resonance imaging

Background

This article reports a rare case of active neurosyphilis in a man with mild to moderate dementia and marked hippocampal atrophy, mimicking early onset Alzheimer’s disease. Few cases have so far described bilateral hippocampal atrophy mimicking Alzheimer’s disease in neurosyphilis.

Case presentation

The patient presented here is a 33 year old Bulgarian male, whose clinical features include progressive cognitive decline and behavioral changes over the last 18 months. Neuropsychological examination revealed mild to moderate dementia (Mini Mental State Examination score was 16/30) with impaired memory and attention, and executive dysfunction. Pyramidal, and extrapyramidal signs, as well as dysarthria and impairment in coordination, were documented. Brain magnetic resonance imaging showed cortical atrophy with noticeable bilateral hippocampal atrophy. The diagnosis of active neurosyphilis was based on positive results of the Venereal Disease Research Laboratory test/Treponema pallidum hemagglutination reactions in blood and cerebrospinal fluid samples. In addition, cerebrospinal fluid analysis showed pleocytosis and elevated protein levels. High-dose intravenous penicillin therapy was administered. At 6 month follow up, improvements were noted clinically, on neuropsychological examinations, and in cerebrospinal fluid samples.

Conclusion

This case underlines the importance of early diagnosis of neurosyphilis. The results suggest that neurosyphilis should be considered when magnetic resonance imaging results indicate mesiotemporal abnormalities and hippocampal atrophy. Neurosyphilis is a treatable condition which requires early aggressive antibiotic therapy.

Neurosyphilis versus Herpes Encephalitis in a Patient with Confusion, Memory Loss, and T2-Weighted Mesiotemporal Hyperintensity

Acute confusion and memory loss associated with asymmetrical mesiotemporal hyperintensity on T2-weighted MRI are characteristic of herpes encephalitis. The authors report the case of a patient with these symptoms and MRI presentation who had neurosyphilis. Recently clinical and imaging patterns usually associated with herpes simplex encephalitis have been seen in patients with neurosyphilis. Because syphilis is "The Great Pretender" not only clinically but also in imaging and because its numbers are rising, it must be sought as a differential diagnosis.

Current approaches to the treatment of paraneoplastic encephalitis

Paraneoplastic neurological syndromes (PNSs) cover a wide range of diseases and involve both the central nervous system (CNS) and peripheral nervous system. Paraneoplastic encephalitis comprises several diseases such as paraneoplastic cerebellar degeneration (PCD), limbic encephalitis (LE), paraneoplastic encephalomyelitis (PEM), brainstem encephalitis, opsomyoclonus syndrome, in addition to other even less frequently occurring entities. LE was the first historically identified CNS PNS, and similarities between other temporal lobe diseases such as herpes encephalitis have been elucidated. In the past few decades several autoantibodies have been described in association with LE. These encompass the classical 'onconeuronal' antibodies (abs) such as Hu, Yo, Ri and others, and now additionally abs towards either ion channels or surface antigens. The clinical core findings in LE are various mental changes such as amnesia or confusion, often associated with seizures. Careful characterization of psychiatric manifestations and/or associated neurological signs can help to characterize the syndrome and type of ab. The treatment options in LE depend on the aetiology. In LE caused by onconeuronal abs, the treatment options are poor. In two types of abs associated with LE, abs against ion channels and surface antigens (e.g. NMDA), immunomodulatory treatments seem effective, making these types of LE treatable conditions. However, LE can also occur without being associated with cancer, in which case only immunomodulation is required. Despite effective treatments, some patients' residual deficits remain, and recurrences have also been described.

Clinical features of neurosyphilis in sex partners

There was a study involving 726 patients with different syphilis forms with the aim of revealing a neurological deficiency in them. Nervous system affection symptoms were founding 298 of them. Neurosyphilis was diagnosed in 165 patients based on the conducted examination. There were five neurosyphilis cases in sex partners among them. The article provides a detailed description of the clinical picture of the disease and discloses the laboratory examination results. The polymorphism of clinical and laboratory manifestations of the syphilitic infection in sex partners can be explained by different terms of infestation, particulars of the immunity and presence of concomitant neurologic and somatic diseases.

Magnetic resonance imaging of infections of the white matter

Infections of the nervous system are a common and serious occurrence. Neuroimaging has allowed to improve early detection and thus to initiate treatment earlier. Magnetic resonance (MR) imaging has become the method of choice in investigating a patient with suspicion of an infection of the central nervous system. Newer modalities such as MR spectroscopy and MR diffusion and perfusion will further help to improve diagnostic accuracy of the technique. For the investigation of infections of white matter, techniques such as diffusion imaging are essential.