Pupils And Prostitutes

Argyll Robertson pupils

“They both accommodate, but don’t react“, and both are associated with neurosyphilis.

You may have remembered the answer from an old Funtabulously Frivolous Friday Five question. It may be politically incorrect, but it sure helps remember the key facts about Argyll Robertson pupils.

• small, irregular, unequal pupils
• near-light dissociation (brisk accommodation but no light reaction)

These features are demonstrated in this classic video:

Near-light dissociation is generally a feature of midbrain lesions that somehow affect iridodilator nerve fibers. the causes include:

• syphilis (true Argyll Robertson pupils — the precise anatomic lesion is poorly understood)
• diabetes mellitus
• alcoholic midbrain degeneration (rare)
• other midbrain lesions, e.g. sarcoidosis, encephalitis, Parinaud syndrome
• abnormal regeneration of the oculomotor (CN3) nerve
• tonic phase of the Holmes-Adie pupil

Sometimes the non-syphilitic pupillary abnormalities are called pseudo-Argyll Robertson pupils.

Douglas Moray Cooper Lamb Argyll Robertson (1837-1909) was a Scottish ophthalmologist. He was the first to describe his eponymous pupillary abnormality among patients with tabes dorsalis.

Argyll Robertson was also the first to demonstrate the cholinergic ocular effects of an extract from the Calabar bean, the drug physostigmine. Later he was consulted by a patient who lived in ‘Old Calabar‘ (in modern day Nigeria) about the ‘Calabar swellings’ that affected her eyes. He extracted filiarial Loa loa worms from these lumps and was thus one of the first to describe ocular loasis.

Parinaud syndrome is also called dorsal midbrain syndrome, it is another cause of near-light dissociation.

Parinaud syndrome is characterised by the following features:

• vertical gaze palsy
• near-light dissociation

It results from direct or compressive injury to the dorsal midbrain, affecting regions such as the superior colliculus adjacent to the oculomotor (CN3) and Edinger-Westphal nuclei (see diagram here).

Causes of Parinaud syndrome include:

• neoplasms, especially pinealomas
• multiple sclerosis
• brainstem CVA
• other causes including: toxoplasmosis of the brainstem, hydrocephalus, trauma, midbrain hemorrhage, and arteriovenous malformations

Named after Henry Parinaud, a French ophthalmologist (1844-1905)

Pearce JM. Parinaud’s syndrome. J. Neurol. Neurosurg. Psychiatr. 2005;76 (1): 99. [PMC1739319]