Case Report: A Case Report of Neurosyphilis Mimicking Limbic Encephalitis

Abstract

Neurosyphilis (NS) is an infection of the central nervous system caused by Treponema pallidum. It mimics various neurological and psychiatric diseases. In recent years, there have been several NS cases that manifest as limbic encephalitis (LE). Therefore, the diagnosis of neurosyphilis in the early stages is difficult. Here, we present a case of an NS patient who presented with LE manifestation. The 62-year-old woman presented with acute clinical manifestations of gibberish speech, poor memory, and seizures. Brain MRI showed abnormal signals on the right medial temporal lobe. In addition, the patient had a positive serum leucine-rich glioma inactivated 1 (LGI1) antibody with a titer of 1:16. Therefore, an initial diagnosis of anti-LGI1 encephalitis was made. However, further tests carried out showed positive rapid plasma reagin (RPR), and treponema pallidum particle agglutination (TPPA) tests both in the serum and the cerebrospinal fluid (CSF). Therefore, uncertainty arose as to whether the patient had both anti-LGI1 encephalitis and NS or whether the LGI1 antibody and LE manifestations were due to the NS. The patient was initiated on the recommended dose of penicillin G sodium. Following treatment, the patient reported a significant improvement in clinical symptoms, normal signals in the right temporal lobe, and a negative serum LGI1 antibody. These findings suggested that NS induced the LE manifestations and the production of the LGI1 antibody. This case demonstrates that testing syphilis in patients with LE is important and positive autoimmune encephalitis (AE) antibodies in NS patients need to be viewed and interpreted with greater caution.

68Ga-FAPI PET/CT Imaging of Intracranial Syphilitic Gumma

“…Neurosyphilis can mimic different diseases, not only in its clinical presentation but also in imaging 2 . Intracranial syphilis gumma should be differentiated from brain metastases, 3 glioma, 1 brain abscess, 4 limbic encephalitis, 5 tuberculous meningitis, 6 lymphoma, 7 and neurocysticercosis 8 . 68 Ga-DOTA-FAPI-04, quinoline-based FAPIs, may have potential value in the detection of various types of cancer 9 .…”

Three cases of neurosyphilis diagnosed in the 21st century: A case report

“…Tabes dorsalis occurs 20-30 years after infection and consists of demyelination of the posterior medullary cords and posterior spinal nerve roots (1). Generalized paralysis (paralytic dementia) occurs 20-30 years after infection and consists of a chronic progressive meningo-encephalitis leading to the destruction of the cerebral cortex in the frontal and temporal lobes (1).…”

“…Tabes dorsalis occurs 20-30 years after infection and consists of demyelination of the posterior medullary cords and posterior spinal nerve roots (1). Generalized paralysis (paralytic dementia) occurs 20-30 years after infection and consists of a chronic progressive meningo-encephalitis leading to the destruction of the cerebral cortex in the frontal and temporal lobes (1). Meningo-vascular syphilis usually occurs 5-12 years after infection and predominantly manifests as microangiopathy, with fibroblastic proliferation of the intima, thinning of the media and lymphocytic infiltration, with narrowing or obliteration of the vascular lumen.…”

“…Syphilis is a sexually transmitted disease whose pathogen is Treponema pallidum, a gram-negative spirochete. The gateway is the tegument or mucous membranes at the level of minimal lesions (1). From a pathophysiological point of view, the main process triggered by Treponema pallidum infection is an obliteration of terminal arterioles, with inflammatory changes and necrosis.…”

“…From a pathophysiological point of view, the main process triggered by Treponema pallidum infection is an obliteration of terminal arterioles, with inflammatory changes and necrosis. In the central nervous system, infection causes chronic inflammation of the meninges and blood arteries, which over time may be complicated by parenchymal lesions (1).…”