Introduction: The diagnosis of Lyme disease in the presence of an acute optical neuritis always raises a difficult diagnostic problem. We present a case of Lyme-associated Leber's hereditary optic neuropathy (LHON).
Observation: A 17-year-old Eurasian young man presented with left-eye visual impairment for 1 month. This loss of vision acuity in the left eye is related to an optic neuropathy. Mitochondrial DNA testing showed a G to A substitution at position 11778 confirming a diagnosis of LHON. The family history disclosed a case of LHON in a maternal cousin. The mother's family is Asian. Besides, serum examination of anti-Borrelia antibodies was performed and was positive against Borrelia burgdorferi garinii. The patient history indicated that he had been possessing a dog and was living in an endemic area of Lyme disease. But he did not recall receiving a tick bite nor having any erythema chronicum migrans. Initial examination showed bilateral green-red axis colour vision defects which made us fear bilateralisation of the optic neuropathy, which occurred 2 months later (that is 3 months after the onset of symptoms on the left eye). An antibiotic treatment by ceftriaxone was administered for 4 weeks all in all; and a long term ubidecarenone therapy was established. At present, after a 1-year follow up, the eyes' conditions remains unchanged.
Conclusion: To our knowledge, this would be the first case reporting such an association, in which we can discuss the fortuitous character or the role of the infectious factor in the developing of the mitochondrial pathology. This observation also raises the problem of the positive diagnosis of Lyme disease when tick bite and erythema are absent or underestimated.