Neurosyphilis, A True Chameleon of Neurology

Abstract

Background: Neurosyphilis (NS) is a rarely encountered scenario today. Manifestations are heterogeneous, and their characteristics have changed in the antibiotic era. A differential diagnosis of NS is not commonly thought of even with relevant clinical-radiological features, as it mimics many common neurological syndromes.

Objectives: To study the manifestations of NS in the present era and the process of diagnosis.

Method: The data of ten patients with NS was collected and analyzed. Their background data, clinical features, investigations, the process of reaching the diagnosis, management and outcomes were recorded.

Observations and results: The manifestations of NS in our cohort included six patients with cognitive decline/encephalopathy and one each with meningitis with cranial nerve palsies, cerebellar ataxia, myelitis and asymptomatic NS. The presence of Argyll Robertson pupil helped to clinch diagnosis in one patient. Treponemal tests were ordered in two patients only after alternative etiologies were looked at, to begin with, whereas in six patients treponemal test was requested as a part of standard workup for dementia/ataxia.

Conclusions: NS dementia and behavior changes are mistaken for degenerative, vascular, nutritional causes, autoimmune encephalitis or prion disease. Meningitis has similarities with infective (tubercular), granulomatous (sarcoidosis, Wegener's), collagen vascular disease and neoplastic meningitis, and myelitis simulates demyelination or nutritional myelopathy (B₁₂ deficiency). Rarely, NS can also present with cerebellar ataxia. Contemplate NS as one of the rare causes for such syndromes, and its early treatment produces good outcomes.

Keywords: Asymptomatic neurosyphilis; cerebellar ataxia; dementia; meningitis; myelitis.

Figure 1

(a) Diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) axial MRI brain sequences of a patient who presented with gradual onset cognitive decline with seizures. Images show infarcts in the right temporal and parietal lobes and bilateral postero-medial thalami. Bilateral periventricular and right frontal lobe FLAIR hyperintensities are also seen (b) The MRI brain axial sequences including T1-weighted (T1W), T1W contrast, T2-weighted (T2W), and FLAIR of another patient who had meningitis with hearing impairment. The MRI shows pachy-meningeal enhancement in bilateral anterior frontal regions

Figure 2

Argyll Robertson pupils (ARP) in a patient with neurosyphilis who presented with gradual onset cognitive decline with parkinsonism

Figure 3

The MRI spine (a and b- T2W and T1W contrast sagittal, c- T1W, T1W contrast, and T2W axial) showing a hyperintense signal in the cervical spine at the C2–3 level and a much longer one in the thoracic spine, mainly in the posterior portion of the cord (black arrow) from the T2 to T11 level, with contrast enhancement, giving candle-gutter appearance (white arrows). There was not much cord swelling seen