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Neurosyphilis emerging in HIV-infected individuals

Detective novels sometimes employ diseases as underlying explanations for precarious situations, and 50 years ago, it wasn’t uncommon for authors to use a disease that languishes for years and has an insidious onset—neurosyphilis—as an explanation for a antagonist’s erratic behavior. Neurosyphilis occurs when untreated syphilis invades the brain and spinal cord, and appears approximately 10 to 20 years later in approximately 25% to 40% of untreated individuals after the initial infection.

Common prior to the invention of penicillin in the 1930s, rates of neurosyphilis declined pursuant to significantly improved treatments, and better screening. By 2009, only 0.21 cases of neurosyphilis per 100,000 Americans were diagnosed. However, statisticians began to see alarming increases in the number of cases after that time.

The American Journal of Medicine has published a new article that describes the reemergence of neurosyphilis, and identifies HIV coinfection in individuals in Western countries as a key risk factor. Because neurosyphilis has become a rarity, many clinicians are unfamiliar with the symptoms, and may fail to diagnose active cases.

A main driver of the reemergence of neurosyphilis is the increase in numbers of cases of syphilis among men who have sex with men. The authors note that coinfection of HIV and syphilis increases HIV viral load in cerebrospinal fluid. Coinfected individuals are also more likely to fail to respond to antibiotic treatment for the initial infection.

This article begins with a case study that highlights symptoms that frequently serve as red flags. The patient reported asthenia (abnormal loss of strength), weight loss, and bilateral red, painful eyes. He also reported severe vision loss, which had been progressive. It was the vision loss that prompted his visit to an emergency room. He was diagnosed with cerebral vasculitis and ischemic stroke secondary to neurosyphilis.
The article highlights the need to increase the index of suspicion in men who have sex with men because they are more likely to fail to respond to treatment for acute syphilis infection. The authors also note that symptomatic neurosyphilis is more likely in patients whose CD4 counts have fallen below 200/mL.

Coinfection with HIV and syphilis requires aggressive treatment following CDC guidelines. For the initial infection, this means employing penicillin G, but acknowledging that treatment failure is possible. Additional studies are needed to identify alternative antibiotics that might be effective.

Development of neurosyphilis requires repeat treatment with penicillin G, with the addition of corticosteroids and low-dose aspirin. While the penicillin is given over a 14 day period, the corticosteroids and low-dose aspirin should consider over 6 months, tapering the corticosteroids at the end.

By Jeannette Y. Wick

Reference
Mageau A, Régent CR, Dion J, et al. Treatment of Syphilis-associated cerebral vasculitis: Reappearance of an old question. Am J Med. 2018 Jun 30. pii: S0002-9343(18)30554-0. doi:10.1016/j.amjmed.2018.06.005. [Epub ahead of print]

Source:
Pharmacy Times
News categories: STIs