Pharmacologic anisocoria due to nebulized ipratropium bromide: A diagnostic challenge.

Anisocoria may be physiological or seen in fatal conditions, such as intracranial hemorrhage. Newly developing anisocoria may cause confusion and diagnostic difficulty in the emergency department (ED). A 35-year-old female was admitted to the ED with an asthma attack and dyspnea. On examination, the patient was observed to have bilateral rhonchi and was treated with nebulized albuterol (salbutamol) and ipratropium bromide. After the treatment, the dyspnea improved, and mydriasis developed in the left eye (left pupil diameter 9 mm, right 4 mm). An examination revealed that the left pupil was dilated and unreactive to light, but there was no neurological finding. Afterwards, the patient reported that, during the treatment, some aerosol had leaked from the left side of the mask and may have come into contact with her left eye. Given this information, a pilocarpine test was performed, and the patient was diagnosed with pharmacologic anisocoria. The pupil returned to normal within 24 h. Ipratropium bromide is a drug frequently used in patients presenting to the ED with dyspnea. During treatment, nebulized ipratropium may leak from the edge of the facial mask into the ipsilateral eye and may cause mydriasis. A pilocarpine test can be used to differentiate pharmacological anisocoria from other causes, such as third nerve palsy and Adie's pupil. Through the awareness of emergency physicians and the use of the pilocarpine test, a diagnosis can be made without engaging in time-consuming and costly analyses. In addition, this complication can be prevented using masks that better fit the face, as well as protective goggles or eye patches, during treatment.