What is Syphilis Ocular Manifestations?
Originally, the disease we now know as syphilis was named “French disease” by the people of Naples, who believed the French troops spread the disease during an invasion in the late 1400s. The current name, “syphilis,” comes from a character in a poem by physician and poet Girolamo Fracastoro. He wrote about the impact of the disease in Italy in 1530. Syphilis is most often spread through sexual contact, and it progresses through different stages: primary, secondary, latent, and tertiary. When the disease passed from a mother to her unborn child, it’s called congenital syphilis.
Syphilis can affect the eyes in several ways and mimic other eye conditions, leading to it being called, “the great imitator.” These eye problems can occur at any stage of the disease and include inflammation of the middle and inner layer of the eye, changes in the cornea, recurring inflammation of the front part of the eye, inflammation of the blood vessels in the retina, and damage to the optic nerve. If left untreated, ocular syphilis can cause blindness and may be associated with neurosyphilis, which is the stage where the disease affects the nervous system.
Disease diagnosis involves a clinical exam complemented by blood tests. But there’s good news: effective treatment exists and usually involves a course of antibiotics.
What Causes Syphilis Ocular Manifestations?
Syphilis is an infection that comes from a kind of bacteria called a spirochete, specifically one known as Treponema pallidum. Spirochetes are bacteria that are long, twisted, and can move around because of something they have called flagella. This particular kind of bacteria was first discovered in the skin sores of people with syphilis in 1905.
Treponema pallidum is quite small, only about 0.01 to 0.02 microns wide and 5 to 20 microns long. This is so tiny that you can’t see it under a regular microscope. It takes a special kind of microscope that uses dark light, called a darkfield microscope, to be able to see it.
Risk Factors and Frequency for Syphilis Ocular Manifestations
The origin of syphilis, a sexually transmitted disease, has been a topic of debate for many years. Two main theories exist: one believes the disease came to Europe from America by Christopher Columbus’s crew, while the other theory suggests that syphilis was present in Europe during the time of Hippocrates but was misdiagnosed and overlooked. These ideas are known as the “Columbian” and “pre-Columbian” hypotheses.
The first recorded outbreak of syphilis happened in Italy in the late 15th century. The disease quickly spread and became widespread in Europe during the 18th and 19th centuries. However, it began to decline rapidly in the early to mid-20th century due to the widespread use of antibiotics. Notably, since the early 2000s, syphilis rates have been steadily increasing again, especially in the U.S., Australia, and Europe, particularly among men who have sex with other men.
- In the U.S., an estimated 55,400 new syphilis cases occur each year.
- In 2018, men made up about 86% of all U.S. syphilis cases.
- Syphilis is also frequently seen in individuals co-infected with HIV.
- The disease can be challenging to diagnose and has more severe impacts on those with AIDS.
Signs and Symptoms of Syphilis Ocular Manifestations
Syphilis, a disease that’s acquired and progresses if untreated, is usually divided into four stages – primary, secondary, latent, and tertiary. At any of these stages, it can cause different eye problems, leading to varied symptoms.
Interestingly, not every patient with syphilis symptoms in the eyes shows signs of the disease throughout their bodies. In the secondary stage, eye symptoms can show up six months after the first infection, by which time other body symptoms may have disappeared. Almost half of those in the tertiary stage showing eye symptoms also have symptoms in other parts of their bodies. This highlights why it’s important to take a detailed history when examining a patient showing eye symptoms linked with syphilis. Usually, inflammatory conditions like episcleritis, iridocyclitis, and retinitis are associated with secondary syphilis, while long-term gummatous or granulomatous inflammation in the eye usually indicates tertiary syphilis. However, there’s considerable overlap between the stages.
Here’s how ocular (eye) manifestations often show up in syphilis:
- Primary Syphilis: This stage is marked by the direct infection of T. pallidum at the local site. Eye manifestations at this stage are rare and usually confined to sores or chancres on the eyelid and the inner surface of the eyelid (conjunctiva) due to direct contact with infected secretions, or from the patient’s own infected fingers.
- Secondary Syphilis: If primary syphilis is untreated, it develops into secondary syphilis in 4 to 10 weeks. This stage might cause a widespread rash that could cause blepharitis (inflammation of the eyelids) and madarosis (loss of eyelashes). Other possible symptoms include conjunctivitis, episcleritis, scleritis, keratitis, iridocyclitis, and anterior uveitis, which are characterised by inflammation of different parts of the eye. It could also lead to Vitritis, necrotizing retinitis, chorioretinitis, retinal vasculitis, optic neuritis, and acute posterior placoid chorioretinopathy (APPC). Some of these conditions affect the eye’s ability to focus light, while others damage the retina and optic nerve.
- Tertiary Syphilis: The long-term inflammation from a granulomatous lesion or gumma, which heals with scarring, is a typical sign of tertiary syphilis. This condition can affect the eyelids and other parts of the eye, leading to keratitis, iridocyclitis, vasculitis, and other damaging conditions. Lastly, Argyll Robertson pupils and optic atrophy are also common.
- Congenital syphilis: The most common eye manifestation in cases of congenital syphilis, which is passed from mother to baby during pregnancy or childbirth, is interstitial keratitis in both eyes. It can also cause pigmentary retinitis and secondary glaucoma due to congenital syphilitic keratouveitis.
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Always remember that any stage of syphilis can seriously affect your eyes, causing conditions that lead to pain, inflammation, blurry vision, or even blindness. Hence, seeking medical attention and following the prescribed treatment is essential.
Testing for Syphilis Ocular Manifestations
If your doctor suspects you have syphilis, they’ll complete an eye examination. This test might include checking your pupil response, vision clarity, and using special equipment to examine up close the various parts of your eye. Other tests, like fundus biomicroscopy (which gives detailed images of your retina), might be needed depending on your individual case.
Additionally, the doctor needs to confirm that you have syphilis, and for this, there are a few laboratory methods. One is darkfield microscopy, in which tissue fluids are put under a microscope to look for bacteria known as spirochetes that cause syphilis. It is, however, quite a demanding task to distinguish between different types of spirochetes, so well-experienced operators are needed.
Another approach to diagnose syphilis is serological testing, which detects antibodies, the body’s immune response to the bacteria. Serological tests can be divided into ‘treponemal’ and ‘non-treponemal’. In non-treponemal tests, such as the VDRL and RPR (rapid plasma reagin) tests, they search for antibodies that the body produces against cardiolipin, a byproduct of the bacteria. However, these tests are most effective during the early stages of syphilis. During the latter stages, only approximately 70% of tests will correctly show the presence of syphilis.
Treponemal tests, on the other hand, are highly specific for the syphilis bacteria. Examples include the enzyme immunoassay (EIA), T. pallidum hemagglutination tests (TPHA), and fluorescent treponemal antibody absorption test (FTA-ABS). These tests remain positive during the entire course of the individual’s life. Nonetheless, they risk showing false-positive results in patients with various diseases or pregnant women. Thus, to ensure a diagnosis of syphilis, your doctor will often use both types of tests and will consider your personal and medical history.
In future, the polymerase chain reaction (PCR) technique, which multiplies segments of DNA for identification, might be used to detect the syphilis bacteria in samples taken from the eye.
Finally, once a diagnosis of syphilis has been made, your doctor will perform a spinal fluid test to determine if it has spread to your nervous system. This is crucial as it changes how syphilis is treated. They will also screen you for HIV, as the two diseases are often transmitted together and can present similarly.
Treatment Options for Syphilis Ocular Manifestations
Antibiotics are the main treatment for ocular syphilis, a condition where the bacterium that causes syphilis infects the eye. However, doses of certain medicines applied directly to the eye can also help to relieve the immediate symptoms. These medications include steroids and drugs called NSAIDs, mydriatics like atropine, and eye lubricants. Your eye doctor will suggest these treatments as needed.
When treating ocular syphilis, doctors will approach it as though they’re treating a condition called neurosyphilis—this is because both conditions involve the spreading of the syphilis bacterium to either the eyes or the nervous system.
General guidelines from the Centers for Disease Control and Prevention (CDC) advise on how to treat ocular syphilis. The standard treatment for early-stage syphilis (primary and secondary syphilis) is an injection of a type of penicillin called penicillin G benzathine. If patients are allergic to penicillin, they can take alternatives such as doxycycline, ceftriaxone, tetracycline, or azithromycin.
For later stages of the disease (latent and tertiary syphilis, including neurosyphilis), the usual treatment is an IV infusion of penicillin G or injections of benzathine penicillin G. Patients allergic to penicillin can also use ceftriaxone and azithromycin as alternatives.
Pregnant women with syphilis are treated exclusively with penicillin—this is the only antibiotic proven to be safe and effective in these cases. Women who are allergic to penicillin would need to undergo a procedure to remove the allergy before getting treated with penicillin G.
Oral steroids and supplements are also often needed to manage inflammation in the eye, and should be taken along with antibiotics. Steroids should not, however, be used before starting antibiotics as it could worsen the disease and lead to dire consequences—such as a risk to the patient’s life or vision.
Once the treatment for syphilis starts, patients should do a blood test known as VDRL every three months for a year after their treatment. The results of this test should show that the syphilis bacterium is no longer present within a year of starting treatment. If test results suggest the bacterium is still present, patients may need to revisit their treatment plan.
What else can Syphilis Ocular Manifestations be?
Syphilis is a complex disease that can cause symptoms similar to many eye diseases. Because of this, syphilis must be considered as a possible cause when a doctor is trying to identify the source of any inflammation in the eyes.
The conditions that are most often mistaken for syphilis affecting the back of the eye (known as posterior syphilis) include:
- Intermediate uveitis
- Non-infectious uveitis related to other diseases like sarcoidosis, systemic lupus erythematosus, and rheumatoid arthritis
- White dot syndromes
- Diseases affecting the blood vessels in the back of the eyes, like macular choroiditis and serpiginous choroidopathy
- Inflammation of the back of the eye due to other causes, also known as chorioretinitis
- Acute retinal necrosis (ARN)
- Progressive outer retinal necrosis (PORN)
- Infections causing inflammation at the back of the eye like toxoplasmosis, cytomegalovirus retinitis
- Other causes of inflammation of blood vessels, like tuberculosis and Behcet disease
What to expect with Syphilis Ocular Manifestations
If the disease is spotted and dealt with quickly, most people recover without any long-term effects. However, if left untreated, around 25% of patients experience one or more relapses throughout their lives. Out of these, most remain in the latent or “hidden” stage of the disease. But, roughly one-third progress to what’s called tertiary syphilis, an advanced stage of the disease.
Possible Complications When Diagnosed with Syphilis Ocular Manifestations
Ocular syphilis can cause several long-term complications for the eyes. These complications might include:
- Corneal opacity: A condition where the front part of your eye, the cornea, becomes less transparent.
- Cataract: Cloudiness in the lens of your eye, which can blur vision.
- Glaucoma: A group of eye conditions that damage the optic nerve, often due to high pressure in the eye.
- Epiretinal membrane: A thin layer of tissue that grows over your retina, which can distort vision.
- Macular edema: A condition where fluid and protein deposits collect on or under the macula of the eye, causing it to thicken and swell.
- Optic atrophy: This is damage to the optic nerve that can result in vision loss.
- Chorioretinal scarring: Scar formation at the back of the eye, leading to potential vision loss.
- Choroidal neovascularization: This is a rare condition that involves the growth of new blood vessels, which can cause serious vision problems.
Preventing Syphilis Ocular Manifestations
Your doctor and nurse will give you advice on how to avoid spreading the infection. This includes not having sex while your symptoms are active and practicing safe sex by using protection like condoms. It’s important to let any sexual partners know, so that they can be tested for syphilis and other sexually transmitted diseases.
If you also have HIV, you’ll need to stay in treatment for a longer period and have regular check-ups. If you’re pregnant, your doctor will talk to you about the risk of passing the infection to your baby. This means you’ll need to regularly see your pregnancy doctor (obstetrician) for check-ups.
