What might cause a unilaterally dilated pupil?

A unilaterally dilated pupil, also known as mydriasis, can occur due to several reasons involving neurological or pharmacological influences. In this case, the inadvertent absorption of a breathing treatment refers specifically to the use of medications such as anticholinergic agents or certain aerosolized treatments that can lead to dilation of the pupil on one side.

When a medication intended for inhalation is absorbed systemically, it can affect the nervous system, particularly the autonomic pathways that control pupil size. If one pupil is affected more than the other, it results in a unilateral dilation. This is why inadvertent absorption of a breathing treatment could lead to this symptom.

While other options might cause changes in pupil size, they typically do not result in unilateral dilation. For instance, excessive sunlight generally affects both pupils, infection may cause systemic responses that lead to other symptoms, and high fever typically leads to bilateral changes as well. Understanding the specificity of different medications and their effects on pupillary responses is essential in trauma and emergency care, particularly for pediatric patients.