One in eight people with isolated polymyalgia had inflammation behind the eye

Design

retrospective observational study with contrast-enhanced orbital MRI

Population

73 patients with isolated polymyalgia rheumatica and 63 with combined giant cell arteritis and polymyalgia

Primary outcome

inflammatory intraorbital MRI findings and their correlation with reported visual symptoms

Effect

intraorbital changes in 12.3% of isolated polymyalgia and 31.7% of combined disease; 4 of 14 symptomatic combined-disease patients had normal scans

Giant cell arteritis and polymyalgia rheumatica are increasingly treated as one spectrum, but what happens in the orbit outside overt arteritis has not been described. This retrospective study assessed contrast-enhanced orbital MRI in patients with isolated polymyalgia and in those with combined giant cell arteritis and polymyalgia, looking for optic nerve sheath enhancement and ophthalmic artery vessel wall enhancement.

Among 73 patients with isolated polymyalgia, nine (12.3 per cent) had intraorbital inflammatory change — bilateral optic nerve sheath enhancement in eight and bilateral ophthalmic artery enhancement in four. None of them had clinical or imaging evidence of large-vessel vasculitis. Two reported acute visual symptoms, and both had corresponding MRI findings. Among 63 patients with combined disease, 20 (31.7 per cent) had intraorbital findings; of 14 reporting acute visual symptoms, ten had matching MRI changes and four did not.

This does not mean scanning every polymyalgia patient's orbits. It means the assumption that visual symptoms in someone labelled 'just polymyalgia' can be dismissed is unsafe. Those four MRI-negative patients with visual symptoms in the combined group are the other half of the lesson: a normal orbital MRI does not exclude the problem either, and the decision to treat visual symptoms in this spectrum remains clinical and urgent.

• Treat new visual symptoms in polymyalgia as an emergency, not as an argument that the diagnosis is wrong
• Do not use a normal orbital MRI to withhold treatment when symptoms point to ischaemia
• Ask about transient visual loss, diplopia and jaw claudication at every polymyalgia review
• Consider orbital MRI where symptoms are equivocal and the answer would change management
• Remember the enhancement here was usually bilateral, which is not the classic arteritic picture

Why it matters

It undermines the reassurance implicit in a polymyalgia label when a patient reports visual symptoms.

Don't overread it

Retrospective imaging in selected patients — this shows inflammation is visible, not that it causes visual loss or that scanning changes outcomes.

The statistics, in plain English

Nine positive scans out of 73 is a small numerator: the 12.3 per cent figure has wide uncertainty around it, and this was a retrospective series of patients who had orbital MRI for some reason, so it is not the prevalence in all polymyalgia. The four symptomatic patients with normal scans matter more than the percentage — they set the test's ceiling as a rule-out.

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