Summary about Disease
Third cranial nerve palsy, also known as oculomotor nerve palsy, occurs when the third cranial nerve, which controls several muscles responsible for eye movement and pupil constriction, is damaged. This damage leads to weakness or paralysis of these muscles, resulting in characteristic signs and symptoms. The severity can vary from mild to complete paralysis.
Symptoms
Ptosis (drooping eyelid): Weakness of the levator palpebrae superioris muscle, which raises the upper eyelid.
Diplopia (double vision): Misalignment of the eyes, causing the brain to receive two different images.
Eye deviation: The affected eye may be turned outward (down and out).
Pupil dilation: The pupil of the affected eye may be larger than normal (mydriasis) and unresponsive or poorly responsive to light.
Difficulty moving the eye: Inability to move the eye up, down, and inward.
Headache: May be present, especially if the palsy is caused by an aneurysm or other compressive lesion.
Causes
Vascular disease: Ischemic stroke, diabetes, or hypertension affecting the blood supply to the nerve.
Aneurysm: Swelling of a blood vessel that can compress the nerve. Specifically, posterior communicating artery aneurysms.
Trauma: Head injury damaging the nerve.
Tumors: Growing near the nerve and compressing it.
Inflammation/Infection: Meningitis, sarcoidosis, or other inflammatory conditions affecting the nerve.
Migraine: Rarely, a migraine can cause a temporary third nerve palsy.
Congenital: Present at birth (rare).
Medicine Used
Pain relievers: To manage headaches, if present.
Corticosteroids: To reduce inflammation in certain cases, such as those caused by inflammatory conditions.
Medications to manage underlying conditions: Such as diabetes, hypertension, or high cholesterol.
Botulinum toxin (Botox) injections: May be used to improve eye alignment and reduce double vision, but the effects are temporary.
Prism glasses: Can help to correct double vision.
Is Communicable
No, third cranial nerve palsy is not communicable. It is not caused by an infectious agent and cannot be spread from person to person.
Precautions
Address underlying medical conditions: Meticulous management of diabetes, hypertension, and other risk factors for vascular disease can help prevent future occurrences.
Safety measures: Take precautions to avoid falls and injuries due to impaired vision.
Regular medical check-ups: To monitor the condition and any underlying causes.
Eye protection: If the eyelid doesn't close fully, use artificial tears and eyelid taping at night to prevent corneal damage.
How long does an outbreak last?
Third cranial nerve palsy is not an "outbreak" like an infectious disease. The duration of the palsy depends on the underlying cause. If the cause is treatable (e.g., inflammation), the palsy may resolve within weeks or months. If the cause is irreversible (e.g., severe nerve damage from trauma), the palsy may be permanent. Even for vascular causes, recovery can take many months, and may not be complete.
How is it diagnosed?
Neurological examination: Assessment of eye movements, pupil response, and other neurological functions.
Neuroimaging: MRI or CT scan of the brain and orbits to identify the cause of the palsy (e.g., aneurysm, tumor, stroke).
Blood tests: To rule out underlying medical conditions such as diabetes, hypertension, or inflammatory disorders.
Angiography (CTA or MRA): To evaluate the blood vessels and rule out aneurysms or other vascular abnormalities.
Timeline of Symptoms
The onset of symptoms can vary depending on the cause.
Sudden onset: Common with vascular causes, aneurysms, or trauma. Symptoms appear within minutes to hours.
Gradual onset: More likely with tumors or inflammatory conditions. Symptoms develop over days, weeks, or even months.
Fluctuating: Rarely, may be associated with migraines or other conditions.
Important Considerations
Urgent evaluation: Any new onset of third cranial nerve palsy requires prompt medical evaluation to rule out serious underlying conditions like aneurysms or tumors. Especially if associated with headache.
Pupil involvement: The presence or absence of pupil involvement can help differentiate between compressive lesions (often pupil-involving) and ischemic causes (often pupil-sparing).
Underlying cause: Treatment is directed at the underlying cause.
Surgical intervention: May be necessary for aneurysms or tumors compressing the nerve.
Vision correction: Prism glasses or surgery may be needed to correct double vision if the palsy is permanent.
Long-term management: Monitoring for complications and addressing any residual symptoms is crucial.