Mesiotemporal changes on magnetic resonance imaging in neurosyphilis

Area of Science:

• Neurology
• Infectious Diseases
• Radiology

Background:

• Neurosyphilis is a complex infection of the central nervous system caused by Treponema pallidum.
• Herpes simplex encephalitis (HSE) is a common cause of viral encephalitis, often presenting with characteristic mesiotemporal lobe abnormalities on MRI.
• Distinguishing between neurosyphilis and HSE can be challenging due to overlapping clinical and imaging features.

Observation:

• A case is presented where neurosyphilis mimicked HSE on magnetic resonance imaging (MRI) brain scans.
• The patient exhibited mesiotemporal changes on MRI, typically associated with HSE, but tested negative for herpes simplex virus in cerebrospinal fluid.
• A literature review identified 24 similar cases globally, linking neurosyphilis with mesiotemporal MRI findings.

Findings:

• Neurosyphilis can manifest with mesiotemporal MRI abnormalities, a pattern historically attributed to HSE.
• Cerebrospinal fluid analysis for herpes simplex virus may be negative in neurosyphilis cases presenting with HSE-like imaging.
• The concurrence of mesiotemporal changes and neurosyphilis is more frequent than previously recognized.

Implications:

• Neurosyphilis should be strongly considered in the differential diagnosis for patients presenting with mesiotemporal MRI abnormalities, even when HSE is suspected.
• This broadens the diagnostic considerations for "the great imitator," emphasizing the need for comprehensive infectious workups.
• Clinicians and radiologists should be aware of this potential imaging overlap to ensure timely and accurate diagnosis and treatment of neurosyphilis.