Medical Fun Facts Podcast

MFF0034: The great imitator

If I’ve timed this correctly, today is Australia Day, 26 January 2017. Happy Australia Day listeners. Today Australians celebrate the arrival of the first fleet more than 200 years ago when Europeans came to settle in Australia. I hope you had a meat pie for lunch.

So, syphilis’s claim to fame is that it is the great imitator. This is an old disease and described in many ancient texts. The manifestations of syphilis are protean.

Learning about syphilis in a textbook is one thing, but it’s not until you see and hear of real examples that a life-long interest can develop. One of the things that attracted me to working in the Top End (i.e., the Top End of the Northern Territory of Australia) was when Professor Frank Bowden visited Brisbane in 1995. It was for a meeting of the Sexual Health Society of Queensland. I was in my final year of training and a member of the society. I didn’t at that stage have a consultant job lined up for 1996, assuming of course that I would pass my final examinations. Part of Frank’s presentation was on syphilis in the Top End. I remember he showed us anal lesions from young Indigenous boys and it was the first time I’d seen secondary syphilitic lesions. The way Frank described the situation was compelling. I owe a lot to Frank in terms of my career progression. It is wonderful to work with him again in Canberra.

Syphilis is caused by a spirochæte, viz., Treponema pallidum subspecies pallidum. There are three other subspecies and each causes a slightly different disease. One is responsible for yaws, another for pinta and the fourth subspecies causes endemic syphilis.

Diagnosing syphilis infections isn’t easy. It’s not easy to grow Treponema pallidum subspecies pallidum unless you have rabbit testes available. The traditional approach is to apply two tiers of testing with non-treponemal and treponemal tests. A lot has changed since the first tests were developed but basically, in nonendemic areas, a non-treponemal assay is applied first and then confirmed with a treponemal assay. In endemic areas, like parts of Australia where the population may be Indigenous Australians, using a treponemal assay first to exclude infection especially for screening purposes, has some advantages.

These days a lot of syphilis testing can be automated and is based on treponemal assays. The main reason for testing is to detect maternal infection. It’s an antenatal screening test. Reactive results mean the patient has to be followed up and if an infection is likely, treatment needs to be offered to prevent congenital syphilis. Syphilis is also tested for before blood donation because it is an important blood-borne pathogen. As a side note, all too often I hear people use the phrase blood-borne viruses and I think that is unfortunate because we should never forget syphilis. One of the greatest diseases in humans.

So how is syphilis spread? I’ve mentioned it can be spread via blood transfusion and congenitally, but it’s through sexual contact that most syphilis is spread. This can be via vaginal penetration, cunnilingus, fellatio as well as other variations where mucous membranes can touch mucous membranes in a vigorous and I hope enjoyable fashion.

This is why barrier protection like condoms and dental dams still have a place. While we have good prophylactic medications for HIV and contraception can largely be managed chemically, creating a physical barrier to stop the spread of infecting microorganisms is still an important feature of good sexual health. Did you also know that if you’re an extreme pubic hair groomer, with >11 total hair removal episodes a year, you have a higher risk of a sexually transmitted infection? Food for thought as you’re trimming, shaving and waxing this weekend.

Syphilis comes in three stages each with its own manifestations of the disease.

Primary syphilis is characterised by painless ulcers or chancres wherever you’ve had sexual contact, mainly the penis and vulva, but also inside the mouth and around the anus. For those into Spanish sex, the risk isn’t as high. You’re going have to look that up, just don’t do it on a work IT system, unless you work in healthcare, then you can say it was part of your job. Now, these chancres will disappear after 3 to 6 weeks even without treatment. That doesn’t mean you don’t need treatment though. It just means the ulcer has healed. You’re still syphilitic.

Secondary syphilis is manifested with skin rashes and sores in the mouth, vagina, and anus. The rash can appear as the primary lesion heals or weeks after. The rash can appear as a non-pruritic blotch on your palms and soles. At the same time, you may have a fever, swollen lymph nodes, a sore throat, patchy hair loss, headaches, weight loss and fatigue. Again, like primary syphilis, these symptoms will pass too even without treatment. Without treatment though, you’re still syphilitic.

If you remain untreated, tertiary or late or latent syphilis may manifest. This can be many years after the initial infection. You may have forgotten all about that painless sore on your labia or the snail-track ulcers in your mouth or the coalescing papules that were growing around your anus. If you think you may have had some of those symptoms and never got them checked out, you may want to visit your doctor.

If you’ve been through the first two stages and you have not been treated or inadvertently treated by receiving a reasonable dose of an appropriate antimicrobial for some other infection, then you have latent syphilis.

After latent syphilis comes tertiary syphilis. Tertiary syphilis can have three pathological branches and it is tertiary syphilis that gives syphilis the title of the great imitator. It’s tertiary syphilis that makes syphilis a king or queen of infections.

The three forms are gummatous syphilis, neurosyphilis and cardiovascular syphilis.

Gummatous can occur up to 20 to 30 years after the initial infection and it’s manifested by tumour-like balls of inflammation that form in bone, skin, liver and anywhere else in your body.

Neurosyphilis means an infection of the central nervous system. You can develop subacute meningitis, general paresis or tabes dorsalis which is associated with poor balance and lightning pains in the legs. Neurosyphilis is associated with seizures and dementia. A great medical student sign to look for is the Argyll Robertson pupils. This means your pupils constrict when you focus on something near but they don’t constrict when a torch is shone in your eyes.

The most spectacular manifestation of tertiary syphilis is cardiovascular syphilis when you develop vascular aneurysms often in the ascending aorta and the aortic arch. These aneurysms can grow quite large. They rupture suddenly and then you just peacefully fade away. It’s like when a bronchoscopist sees big red and gets too close and accidentally takes a biopsy.

The other important manifestation is congenital syphilis. Babies can be born with unfortunate deformities.

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