What is Argyll Robertson Pupil?
The Argyll Robertson pupils is a condition where both pupils of the eyes are small and won’t shrink when exposed to bright light. However, they will shrink when focusing on something close-by. This is a condition specifically related to an advanced stage of syphilis, a sexually transmitted infection. The condition was first identified in the middle of the 1800s by Dr. Douglas Argyll Robertson, a famous Scottish eye doctor and surgeon. To date, we still don’t know why this happens, but it visibly impacts the eye’s reaction to light.
This condition typically comes with other signs of advanced syphilis, which helps doctors diagnose and treat it. Syphilis is primarily spread by contact with bodily fluids from a person with the infection, often during sexual contact with a syphilis sore, or from an infected mother to her unborn child. There are less common ways the infection can be passed on as well.
With the increasing number of syphilis cases around the world, doctors from emergency, primary, and internal specialties may come across this condition. In the advanced stage of syphilis, this condition is a serious sign of potential health problems. If correctly diagnosed, syphilis can be easily treated with antibiotics. However, some of the damage to the heart or nerves caused by syphilis may not be reversible.
What Causes Argyll Robertson Pupil?
Argyll Robertson pupils are a condition often seen in the late stages of syphilis, a disease caused by a spiral-shaped bacteria called Treponema pallidum. This type of bacteria has the ability to invade the fluid surrounding the brain and spinal cord, known as the cerebrospinal fluid. This usually happens shortly after a person gets syphilis. However, it’s not fully understood why this leads to the development of Argyll Robertson pupils.
Risk Factors and Frequency for Argyll Robertson Pupil
The condition often seen in eye exams, Argyll Robertson pupils, has become rare in developed countries thanks to the introduction of penicillin. However, cases of primary and secondary syphilis have been on the rise since 2001. The Centers for Disease Control and Prevention (CDC) reported that there were 30,676 cases of this advanced or hidden form of the disease in 2016 in the United States. The CDC, however, believes that the true number is likely higher because not all cases are reported.
From 2000 to 2016, the number of reported syphilis cases increased primarily in men who have sex with men (MSM). This could reflect two possible scenarios: syphilis might be more common in this group, many of whom also have HIV, or it could indicate that there are distinct groups with an increased vulnerability to the disease. There’s a strong overlap of HIV infection among MSM patients who have contracted syphilis. According to CDC, around 5% of MSM with syphilis are also living with HIV.
Reports have also suggested a rising trend of syphilis along with the global HIV/AIDs epidemic.
Signs and Symptoms of Argyll Robertson Pupil
Argyll Robertson pupils is a medical condition where the person has small, irregular pupils. These pupils do not react to light, but they do narrow when the person is focusing on something close up. This condition is usually the same in both eyes and takes months or years to develop completely. At first, the reaction to light may be slow, but then eventually, there might be no reaction at all. During a close look at the eyes, the iris may appear thinner with less distinct features. Also, the pupils might expand slowly to certain eye medications such as atropine.
There are other signs that could potentially indicate the presence of Argyll Robertson pupils, especially if they’re related to late-stage syphilis. These include:
- Tabes dorsalis: A stage of syphilis where the back part of the spinal cord and its connected nerves are affected.
- Sensory ataxia: A lack of coordination due to the loss of ability to sense one’s own bodily position. This is not due to cerebellar damage.
- Lancinating pains: Sudden bouts of sharp pain in the face, back, or limbs that can last anywhere from minutes to days.
- Pupil irregularities: With 50% being distinctive Argyll Robertson pupils.
Testing for Argyll Robertson Pupil
There are several tests to diagnose syphilis, a sexually transmitted infection. The most robust method involves using a microscope to see the syphilis bacteria directly. However, it’s more common to first run blood tests for markers of the disease. These blood markers, called VRDL (Venereal Disease Research Laboratory) or RPR (Rapid Plasma Reagin), can hint at the presence of syphilis in the body.
Once syphilis is suspected based on these initial blood tests, confirmatory testing is done. These tests look for the presence of specific proteins known as FTA-ABS (Fluorescent Treponemal Antibody Absorption), TPPA (Treponema Pallidum Particle Agglutination Assay), or EIAs (Syphilis Enzyme Immunoassays), which can indicate syphilis.
When there is reason to think the infection might have spread to the nervous system (a condition known as neurosyphilis), a lumbar puncture, or spinal tap, may be done. This test is particularly relevant if a patient has symptoms that suggest a neurological or eye disorder linked to syphilis, or if a patient known to have syphilis starts showing these signs. For HIV patients who also have syphilis, a lumbar puncture is commonly recommended to check for signs of neurosyphilis, regardless of the kind of symptoms they’re experiencing. Neurosyphilis could be suggested if the patient has more than 20 white blood cells per microliter in their spinal fluid and tests positive for the syphilis markers VRDL and an antibody linked to syphilis in the spinal fluid.
Treatment Options for Argyll Robertson Pupil
There is no specific treatment for a condition known as Argyll Robertson pupils, but we can manage its progression by treating the disease that causes it, which is often syphilis. The usual treatment for syphilis is an intramuscular injection of a medicine called penicillin G benzathine.
For patients who are allergic to penicillin, we can use an alternative medication called doxycycline, which is taken orally. Another safe alternative for those allergic to penicillin is ceftriaxone.
The choice of antibiotic treatment is usually based on the patient’s medical history and the doctor’s clinical judgment.
What else can Argyll Robertson Pupil be?
Argyll Robertson pupils is a condition that affects the eye, specifically causing issues with how the pupil reacts to light. However, there are other medical conditions that can seem similar because they also affect the way the eye responds to light. These can be either due to problems with the eye taking in light (input failure) or issues with how the eye responds (output failure).
If there is an issue with input, this could be due to damage in the optic nerves (which send visual information from the eye to the brain) on both sides, or issues in the area where these nerves cross (chiasmal lesions), or damage to the nerve paths that carry visual information from the optic nerves to the brain (optic tract lesions). These issues would result in a fake light-near reaction, where the reaction to light is reduced, but the near reaction (how the eye adjusts when you look at things close up) is not affected.
On the other hand, conditions due to output failure include Argyll Robertson pupils itself and other conditions like Adie’s pupil (a pupil that doesn’t react normally to light), the Miller-Fisher variant of acute idiopathic demyelinating polyradiculopathy (a neurological disorder), uncontrolled diabetes, and certain nerve diseases. The size of the pupils is one way to tell these conditions apart: Argyll Robertson pupils are small, while the others have larger pupils.
What to expect with Argyll Robertson Pupil
Argyll Robertson pupils are a strong sign of neurosyphilis, a disease that affects multiple organs and can cause serious health issues. If a patient is diagnosed with Argyll Robertson pupils, it implies they need to start powerful treatment right away to get rid of the infection and stop the disease from progressing. The sooner the condition is diagnosed and treated, the better the chances of a positive outcome for the patient.
Possible Complications When Diagnosed with Argyll Robertson Pupil
The Argyll Robertson pupils only appear in the final phases of syphilis disease. Patients suffering from this condition also tend to have brain and heart-related problems. There are a number of complications that can occur, such as:
- Aneurysm in the aorta (the main blood vessel in the body)
- Aortic valve dysfunction (the valve responsible for blood flow from the heart to the rest of the body)
- Meningitis
- Tabetic disease (causing difficulties in motor coordination and sensory abilities)
While treatment can stop the disease from getting worse, whether the symptoms improve or not depends on how much the disease has progressed. Unfortunately, for patients who have heart or nerve damage as a result of the disease, the damage cannot be reversed and their outlook isn’t very positive.
Preventing Argyll Robertson Pupil
The best way to prevent this disease is through taking steps to stop it from occurring in the first place. Unfortunately, there’s currently no vaccine available for syphilis. It’s suggested that people get sexual education to learn how to avoid passing syphilis on to others.
