Concentration-related mydriasis in a patient with renal dysfunction treated with phenytoin.

BACKGROUND

There is very limited evidence concerning phenytoin-related mydriasis.

METHODS

A 59-year-old male was hospitalized in the intensive care unit due to a head injury. During his hospitalization, phenytoin was administrated. Some days later he presented bilateral mydriasis. At that time he had impaired creatinine clearance 7 ml/min, albumin levels 3.4 gr/dl, and phenytoin serum concentration 19.94 μg/dl. Evaluation with brain computed tomography and magnetic resonance imaging did not reveal any potential cause of mydriasis, while none of the co-administrated drugs have been reported to cause significant mydriasis. After initiation of continuous venovenous hemodiafiltration and discontinuation of phenytoin, mydriasis was reversed.

CONCLUSIONS

Clinicians should be aware that mydriasis due to a toxic concentration of phenytoin may be manifested. Hippokratia 2016, 20(2): 166-168.