Horner syndrome and Cocaine
Action of Cocaine
Cocaine blocks reuptake of norepinepherine that is normally released from nerve endings. In a sympathetic lesion, norepinepherine is not released.
Effects of Cocaine on Horner's pupil
little or no effect
Effects of Cocaine on Normal pupil
dilation
Test procedure
- Place not more than 2 drops of cocaine hydrochloride 10% in both eyes (2% for infants and children,4% and 5% can also work for adults)
- Measure anisocoria 50-60 minutes later
- 0.8 mm or greater anisocoria after the cocaine is highly suggestive of Horner syndrome
False Positive result
pupil held by membrane, scar or aberrant innervation Image