Cotton wool spots in patients with migraine
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Authors: Po Hsiang (Shawn) Yuan, Jonathan Micieli.
Disclosure Block: P. Yuan: None. J. Micieli: None.
report and discuss the association between cotton wool spot (CWS) findings and
Study Design: Retrospective case review.
Methods: We retrospectively reviewed patients presenting to a comprehensive ophthalmology and neuro-ophthalmology practice with CWS. Research ethics board approval from the University of Toronto Research Ethics Board was obtained.
Inclusion criteria included i) negative extensive systemic workup for known CWS etiologies as outlined below ii) history of or subsequent development of migraine with or without aura or typical aura without migraine. Exclusion criteria included i) ocular findings consistent with a retinal vein occlusion, diabetic retinopathy or hypertensive retinopathy ii) branch or central retinal artery occlusion iii) known systemic disease associated with CWS.
For inclusion, the systemic workup must have included a blood pressure less than 140/90, normal hemoglobin A1c (less than 6.0), and systemic evaluation including normal or negative erythrocyte sedimentation rate, C-reactive protein, antiphospholipid antibodies, antithrombin assay, factor V mutation, fibrinogen, homocysteine, lupus anticoagulant, protein C and S assay, prothrombin gene mutation, serum protein electrophoresis, antinuclear antibody, anti-neurotrophil cytoplasmic antibody, rheumatoid factor, C3/4,HIV and VDRL/RPR. Patients must also have had computed tomography or magnetic resonance angiography of the head and neck to rule out carotid disease or signs of vasculitis. Clinical and demographic information were retrieved for analysis.
Results: Four patients (2 male, 2 female) with a mean age of 33.8 years (range 27 to 40) had no known medical conditions apart from migraine. The two female patients were taking oral contraceptive pills. Three patients had a history of migraine (ICHD-3 definition) and one patient developed new typical visual auras without headache 1 month after the discovery of the CWS. Three patients presented due to a new scotoma in the affected eye and one patient had an incidentally discovered CWS during an eye exam for an unrelated reason. The scotoma was described as sudden in all patients and took the form of a “smudge”, “grain of rice”, and a “line”. Two patients had an associated migraine headache at the time of the visual disturbance. In patients with pre-existing migraine, the mean duration of migraine diagnosis was 15.3 years and 2 patients had migraine with visual aura and 1 patient had migraine without aura. Visual acuity and Humphrey visual fields were normal in all patients and dilated fundus examination revealed an isolated CWS in 3 patients and a CWS with an associated hemorrhage in one patient. The subjective scotoma fully reversed in 2 patients and time to resolution ranged from 1 to 9 days. One patient had an improved but persisting small scotoma that was not detectable on formal visual field testing.
Conclusions: CWS may be discovered in the ophthalmic assessment of patients with new visual disturbances or be an incidental finding. Our case series suggests that CWS can be seen in the context of migraine and should be considered in the differential diagnosis for this examination finding. However, this diagnosis should only be made after exclusion of other known causes of CWS including but not limited to hypertension and diabetes.