A 9-year-old girl arrived at Schneider Children's Emergency Medicine Department (ER) recently after her mother noticed a difference in the size of her pupils in her eyes.

A 9-year-old girl arrived at Schneider Children's Emergency Medicine Department (ER) recently after her mother noticed a difference in the size of her pupils in both her eyes. Dr. Asaf Gershoni, an ophthalmologist in the ER, discerned that in addition to the dissimilar pupils, she also displayed limited eye movement as well as a fallen eyelid, concluding that the condition resulted from partial paralysis of the third cranial nerve.

The 3rd cranial nerve serves most of the eye and eyelid muscles, and the muscle of the iris at the rear which contracts the pupil. Paralysis of this nerve, especially when the pupil is involved, is a medical emergency because one of the possible causes could be an aneurysm in one of the brain's arteries pressing along the path of the nerve at the base of the skull.

An emergency angiogram (CT scan of the brain's vessels) confirmed the diagnosis of a brain aneurysm, a very rare occurance in children and life-threatening. If not treated immediately, it could lead to brain hemorrhaging, stroke or death. A cranial catheterization to close the aneurysm was successfully performed by Dr. Shimon Maimon, a cranial vascular specialist in the Neurosurgery Unit at Schneider Children's. The child's condition improved and she was released from hospital a few days later.

According to Prof. Gad Dotan, Director of the Ophthalmology Unit at Schneider Children's, "Due to the mother's awareness that her daughter's pupils were dissimilar in size, the correct diagnosis by the ophthalmologist in the ER, and the speedy and precise brain catheterization performed, we succeeded in avoiding a tragedy and saved the child's life. It is important to emphasize that not every occurance of different-sized pupils means the existence of a brain aneurysm, although should this be a new situation, urgent medical attention must be sought."