With syphilis resurgent among men who have sex with men (MSM) in the United States, researchers are calling on clinicians to maintain greater vigilance in spotting neurosyphilis cases among HIV-positive MSM in particular, Pharmacy Times reports.

If their syphilis infection goes untreated, approximately 25 to 40 percent of individuals will develop neurosyphilis, which occurs after about 10 to 20 years as a result of the sexually transmitted infection infecting the brain and spinal cord.

When people with HIV contract syphilis, the bacterial infection increases HIV viral load in cerebrospinal fluid. Additionally, HIV-positive individuals are more likely to see their syphilis infection fail to respond to antibiotic treatment for the initial infection; they require a more aggressive treatment approach than is standard.

In 2009, the United States saw just 2.1 cases of neurosyphilis per 1 million people. During the years since, the diagnosis rate has increased dramatically.

To call attention to neurosyphilis as an increasingly possible diagnosis among HIV-positive MSM in particular, researchers published a case study in the American Journal of Medicine regarding a 50-year-old man who presented with a number of indications of syphilis-driven neurological damage.

The man experienced severe and progressive vision loss, which prompted him to visit an emergency room. He had asthenia (an abnormal loss of strength) and weight loss, and both of his eyes were red and painful. Clinicians diagnosed him with cerebral vasculitis (inflammation of the blood vessel wall in the brain and usually the spinal cord) as well as ischemic stroke (interruption of blood supply to tissues). The man was unaware until he was diagnosed during his visit that he had HIV; he had a CD4 count of 236.

Symptomatic neurosyphilis is more likely to occur among those with a CD4 count below 200.

Clinicians started the man on antiretroviral treatment for his HIV and gave him intravenous penicillin G and a short course of a corticosteroid. Nevertheless, he ultimately experienced a relapse of symptomatic neurosyphilis. He recovered completely following a second course of penicillin and corticosteroids.

To read the study abstract, click here.