Abstract
Tadpole pupil is a rarely encountered phenomenon caused by episodic, segmental iris
dilator muscle spasm of short duration (2–15 minutes), occurring in clusters without
a known precipitating factor. It has most commonly been described in women aged 28
to 48 years. A few hypotheses on pathogenesis have been discussed but none has been
proved. Here, we present an adolescent girl with bilateral tadpole pupil that appeared
during physical exercise. This is the first pediatric case of tadpole pupil, not caused
by preceding surgery, to be published. Based on (1) this case in which tadpole pupil
developed when the norepinephrine level rose during exercise, (2) the high ratio of
patients with tadpole pupil who concurrently have or later develop Horner syndrome,
in which denervation hypersensitivity is well described, (3) a previous report of
a patient with both tadpole pupil and Horner syndrome who had denervation hypersensitivity
on pharmacological testing, (4) a 29-year-old man with unilateral tadpole pupil induced
by exercise, and (5) a 19-year-old man with bilateral tadpole pupil and possible autonomic
neuropathy, we suggest denervation hypersensitivity as a probable pathogenic mechanism
causing tadpole pupil. In addition, a suggestion for investigations to be performed
in future pediatric cases is provided.
Keywords
tadpole pupil - pathogenesis - denervation hypersensitivity - pediatric
