Ocular Flutter—A Sign of Brain-Stem Pathology as Rare Consequence of Cyclosporin A Treatment

Abstract

Cyclosporin A is a widely used immunosuppressive drug. While neurotoxic side effects are frequent and manifold, oculomotor disturbances have hardly ever been noted. Here, we report the case of a 56-year-old woman, suffering from acute myeloid leukemia (AML) and treated with allogeneic peripheral blood stem-cell transplantation (PBSCT) and supporting cyclosporin, who developed neurological deficits consisting of ocular flutter, severe ataxia, and tremor of trunk and extremities within a few days. Whereas MRI scans of the neurocranium and spinal cord, Doppler ultrasound of the extracranial brain-supplying blood vessels, and the standard repertoire of electrophysiological examinations of the peripheral nerves were inconclusive, a cerebrospinal fluid tap showed an elevated cell count with leukemic blasts documenting leukemic meningitis. As soon as the cyclosporin medication, which had been initiated after the PBSCT 13 weeks earlier, was terminated, the aforementioned disturbances promptly subsided, well before treatment of the meningeosis was commenced. This temporal relationship indicates that ocular flutter as well as ataxia and tremor were caused by cyclosporin-associated neurotoxicity rather than by meningeosis. The isolated oculomotor abnormality of ocular flutter in the absence of typical cerebellar oculomotor disturbances suggests that ocular flutter might be a consequence of brain-stem dysfunction rather than reflecting cerebellar disturbances.

KEYWORDS:

• Acute myeloid leukemia (AML)
• cyclosporin A
• ocular flutter
• omnipause neurons
• peripheral blood stem-cell transplantation (PBSCT)