Aim: Pain is a common feature of microvascular ischaemic ocular motor cranial nerve palsies (MP). The natural history of pain in this condition has not been studied. The purpose of this report is to define the spectrum of pain in isolated MP, with special reference to diabetic versus non-diabetic patients.
Design and methods: Retrospective and prospective chart review was performed on 87 patients with acute-onset MP of a single cranial nerve (CN III, oculomotor; CN IV, trochlear; CN VI, abducens) that progressively improved or resolved over 6 months.
Results: Five of the 87 patients had two events, making the total number events 92. There were 39 (42.4%) CN III palsies, five (5.4%) CN IV palsies and 48 (52.2%) CN VI palsies. Thirty-six (41%) patients had diabetes. Pain was present in 57 (62%) events. The majority of diabetic and non-diabetic patients had pain. Pain preceded diplopia by 5.8 (SD 5.5) days in one-third of events. There was a trend towards greater pain with CN III palsies, but this was not statistically significant. Patients who experienced severe pain tended to have pain for a longer duration (26.4 (SD 21.7) days compared with 10.8 (SD 8.3) and 9.5 (SD 9) days for mild and moderate pain, respectively). There was no correlation between having diabetes and experiencing pain.
Conclusions: The majority of MP are painful, regardless of the presence or absence of diabetes. Pain may occur prior to or concurrent with the onset of diplopia. Non-diabetic and diabetic patients presented with similar pain characteristics, contrary to the belief that diabetic patients have more pain associated with MP.
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Funding A grant from the National Institutes of Health (NIH R21 EY015145-03 – CWRU Clinical Vision Research Initiative), through the Case Western Reserve University Department of Ophthalmology, was used for statistical analysis. This manuscript was supported in part by a departmental grant (Department of Ophthalmology, Emory University) from Research to Prevent Blindness, Inc., New York, USA, and by core grant P30-EY06360 (Department of Ophthalmology, Emory University) from the National Institutes of Health, Bethesda, Maryland, USA.
Competing interests None declared.
Ethics approval Institutional review board approval was obtained from both University Hospitals of Cleveland and Emory University. Waiver of consent and waiver of the Health Insurance Portability and Accountability Act (HIPAA) were obtained at University Hospitals of Cleveland. Waivers of consent for retrospective chart reviews are not necessary at Emory University.
Provenance and peer review Not commissioned; externally peer reviewed.