Oculomotor nerve palsy

A condition affecting the third cranial nerve

Oculomotor nerve palsy
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Double vision, drooping eyelid, pupil dilation
Complications	N/A
Onset	N/A
Duration	N/A
Types	N/A
Causes	Trauma, aneurysm, diabetes, stroke
Risks	N/A
Diagnosis	Clinical examination, imaging
Differential diagnosis	N/A
Prevention	N/A
Treatment	Depends on cause; may include surgery, medication
Medication	N/A
Prognosis	N/A
Frequency	N/A
Deaths	N/A

Oculomotor nerve palsy is a neurological condition characterized by the dysfunction of the oculomotor nerve, which is the third cranial nerve. This nerve is responsible for controlling most of the eye's movements, including constriction of the pupil and maintaining an open eyelid.

Anatomy and Function

The oculomotor nerve innervates several muscles around the eye, including the medial rectus, superior rectus, inferior rectus, and inferior oblique muscles. It also innervates the levator palpebrae superioris muscle, which elevates the eyelid, and provides parasympathetic fibers to the sphincter pupillae muscle, which constricts the pupil.

Causes

Oculomotor nerve palsy can result from various causes, including:

• Trauma: Physical injury to the head can damage the nerve.
• Aneurysm: An aneurysm of the posterior communicating artery can compress the nerve.
• Diabetes mellitus: Microvascular disease can affect the nerve's blood supply.
• Stroke: A stroke affecting the brainstem can impact the nerve's function.
• Tumors: Masses in the brain can exert pressure on the nerve.

Symptoms

The symptoms of oculomotor nerve palsy can vary depending on the extent of the nerve damage but typically include:

• Diplopia (double vision)
• Ptosis (drooping of the eyelid)
• Mydriasis (dilated pupil)
• Eye positioned "down and out" due to unopposed action of the lateral rectus and superior oblique muscles

Diagnosis

Diagnosis of oculomotor nerve palsy involves a thorough clinical examination, including:

• Assessment of eye movements
• Evaluation of pupil size and reactivity
• Imaging studies such as MRI or CT scan to identify underlying causes

Treatment

Treatment of oculomotor nerve palsy depends on the underlying cause:

• Surgical intervention may be necessary for aneurysms or tumors.
• Medical management for diabetes or hypertension.
• Eye patching or prisms for symptomatic relief of double vision.

Prognosis

The prognosis for oculomotor nerve palsy varies. Some cases resolve spontaneously, especially those related to microvascular causes like diabetes. Others may require surgical intervention or may result in permanent deficits.

Also see

• Cranial nerves
• Trochlear nerve palsy
• Abducens nerve palsy
• Diplopia
• Ptosis