Cranial mononeuropathy III is a problem with the function of the third cranial nerve that causes double vision and eyelid drooping.
Alternative Names
Third cranial nerve palsy; Oculomotor palsy; Pupil-involving third cranial nerve palsy; Mononeuropathy - compression type
Causes, incidence, and risk factors
Cranial mononeuropathy III is a mononeuropathy, which means that only one nerve is affected. It affects the third cranial (oculomotor) nerve, one of the cranial nerves that controls eye movement. Local tumors or swelling can press on and damage the nerve.
Tissue damage from loss of blood flow (infarction)
Trauma (from head injury or caused accidentally during surgery)
Tumors or other growths (especially tumors at the base of the brain and pituitary gland)
Rarely, people with migraine headaches may have a temporary problem with the oculomotor nerve. This is probably due to a spasm of the blood vessels. In some cases, no cause can be found.
Enlarged pupil that does not get bigger when a light shines on it
Headache or eye pain
Other symptoms may occur if the cause is a tumor or swelling of the brain. Decreasing alertness is a serious sign, because it could be a sign of brain damage or impending death.
Signs and tests
An eye examination may show:
Enlarged (dilated) pupil of the affected eye
Eye movement abnormalities
Eyes that are not aligned (dysconjugate gaze)
A complete medical and nervous system (neurological) examination is performed to find out if any other parts of the body are affected.
Review Date:
5/31/2012
Reviewed By:
Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
