Keywords
oculomotor nerve - head injury - avulsion
Palavras-chave
nervo oculomotor - traumatismo craniano - avulsão
Introduction
The incidence of primary traumatic oculomotor palsy in craniocerebral trauma is very rare (around 1%), and even rarer in the setting of mild head trauma.[1]
[2]
[3] It is more commonly observed following severe trauma, and it is associated with loss of consciousness and permanent neurologic deficit.[4]
[5]
Case Report
A 37-year-old female, who suffered a mild head injury after a car accident, was found with initial Glasgow coma scale score of 15. On further inspection, she had no abrasions of the forehead, no scalp hematoma and no ptosis, but exhibited a fixed, dilated right pupil ([Fig. 1a], [1b]). An initial computerized tomography (CT) scan of the head was normal. Magnetic resonance imaging performed after 2 days showed right oculomotor nerve avulsion ([Fig. 2]). Magnetic resonance imagining angiogram was normal. The patient was discharged from our hospital 3 days after the injury, without any improvement in complete ophthalmoplegia.
Fig. 1 (A) Right eyelid showing complete ptosis. (B) Right eye is deviated outward and downward, the pupil is dilated and non-reactive to light.
Fig. 2 High-resolution CISS MR image of the mesencephalon showing the right oculomotor nerve is interruption– avulsion of right third nerve (asterisk).
Discussion
To our knowledge, this is the first radiographically documented case of oculomotor nerve root avulsion with associated irreversible oculomotor nerve palsy after mild head injury. After this radiographic diagnosis, a poor prognosis for nerve function is expected. In this context, appropriate counseling should be provided to the patient and family, allowing them to understand the structural damage, and the unlikely nature of spontaneous improvement of clinical symptoms. Neurosurgical techniques for attempting nerve reconstruction have yet to be investigated but could be a new area for clinical and surgical research.[6]
