What happens when the trochlear nerve is damaged?
Injury to the trochlear nerve cause weakness of downward eye movement with consequent vertical diplopia (double vision). The affected eye drifts upward relative to the normal eye, due to the unopposed actions of the remaining extraocular muscles.
What causes 4th cranial nerve palsy?
In adults, the most common cause of fourth nerve palsy is injury. The injury may seem minor. Fourth nerve injury can occur with injuries that cause whiplash or concussions. Another common cause is from poor blood flow related to diabetes.
How is 6th nerve palsy diagnosed?
How to diagnose sixth nerve palsy?
- brain scan to check for a brain tumor, skull fracture, brain injury, or increased pressure in the brain.
- blood test or a lumbar puncture to diagnose or rule out meningitis.
- neurological tests to check for abnormalities in your nervous system.
How do you test for trochlear nerve damage?
To detect excyclotropia one must ask the patient whether there is a tilted double image in down gaze. Bilateral trochlear nerve palsy causes a change of vertical deviation between right and left gaze and between head-tilt to the right and to the left shoulder.
What does cranial nerve 4 palsy look like?
Fourth cranial nerve palsy may affect one or both eyes. Because the superior oblique muscle is paretic, the eyes do not adduct normally. Patients see double images, one above and slightly to the side of the other; thus, going down stairs, which requires looking down and inward, is difficult.
What is cranial nerve 3 palsy?
A palsy of the 3rd cranial nerve can impair eye movements, the response of pupils to light, or both. These palsies can occur when pressure is put on the nerve or the nerve does not get enough blood.
How do you assess CN3?
Extraocular movements (CN 3, 4, 6) are examined by asking the patient to follow a finger or pen or card with the eyes. This tests cranial nerves 3 (oculomotor), 4 (trochlear), and 6 (abducens). CN3 mediates medial deviation and all other directions of movement not coordinated by CN4 and CN6.
Will 6th nerve palsy go away?
Often, symptoms from sixth nerve palsy improve on their own. Sixth nerve palsy following a viral illness often completely goes away within a few months. Symptoms following trauma may also improve over several months. But in cases of trauma, symptoms are less likely to go away completely.
Is 6th nerve palsy an emergency?
Congenital sixth nerve palsies do occur, but they are extremely uncommon. The work-up for these patients may not always need to be completed in the emergency department, but should be done urgently as outpatients and must include a thorough history and physical examination as well as a head CT.