From the Guidelines
Argyll Robertson pupil can be caused by various conditions beyond neurosyphilis, including diabetes mellitus, multiple sclerosis, alcoholism, midbrain lesions, and certain medications, as well as other rare causes such as Lyme disease, sarcoidosis, and Wernicke's encephalopathy. When considering the etiology of Argyll Robertson pupils, it is crucial to evaluate for conditions that may affect the autonomic nervous system or the brainstem, such as diabetes mellitus, which can damage the autonomic nerves controlling pupillary responses 1. Other potential causes include:
- Multiple sclerosis, which can affect the pathways in the midbrain responsible for pupillary light reflexes
- Chronic alcoholism, leading to nutritional deficiencies and brainstem dysfunction
- Structural lesions in the midbrain, such as tumors, strokes, or aneurysms, which can interrupt the light reflex pathway while preserving the accommodation pathway
- Certain medications, like opioids, that can occasionally produce this pupillary finding
- Rare causes including Lyme disease, sarcoidosis, Wernicke's encephalopathy, and Parinaud's syndrome The underlying mechanism typically involves damage to the pretectal nuclei or their projections to the Edinger-Westphal nuclei, disrupting the light reflex while preserving the more diffuse pathways for accommodation 1. In clinical practice, when encountering Argyll Robertson pupils, a thorough neurological examination and appropriate testing for these underlying conditions, including neuroimaging and serologic testing, is essential for proper diagnosis and management, as recommended in the adult strabismus preferred practice pattern 1.
From the Research
Other Causes of Argyll Robertson Pupil
The Argyll Robertson pupil is a clinical sign that has been associated with various conditions. Some of the other causes of Argyll Robertson pupil include:
- Neurosyphilis, as discussed in the study 2, where a patient with newly diagnosed HIV was found to have Argyll Robertson pupils, among other symptoms.
- Other conditions with lesions in the area of the nucleus of Edinger-Westphal, as mentioned in the study 3.
- Sarcoidosis and multiple sclerosis, as reported in the study 3, where magnetic resonance imaging studies have localized the lesion in patients with these conditions.
- Peripheral nerve pathogenesis, as proposed by many authorities and reviewed in the study 4.
- Ciliary (peripheral) denervation, as suggested in the study 5, where segmental iris sphincter palsy is found and the light-near dissociation has tonic features.
- Dorsal midbrain lesion, as attributed in the study 5, although lesions in this region have not been reliably demonstrated in syphilis.
- Tabes dorsalis, as originally associated with the Argyll Robertson pupil, as mentioned in the study 3.
- HIV-encephalopathy, as seen in the patient in the study 2, where a brain MRI showed diffuse cortical atrophy and lesions in the white matter compatible with HIV-encephalopathy.