Differential Diagnosis for 80M with Bilateral Cataracts and Sudden Unilateral Double Vision
Single Most Likely Diagnosis
- Fourth Cranial Nerve (Trochlear Nerve) Palsy: This condition is a common cause of sudden onset unilateral double vision, especially in older adults. The trochlear nerve controls the superior oblique muscle, which is responsible for rotating the eye. A palsy of this nerve can result from a variety of causes, including microvascular ischemia, which is more common in older individuals with vascular risk factors.
Other Likely Diagnoses
- Third Cranial Nerve (Oculomotor Nerve) Palsy: While less common than fourth nerve palsy, third nerve palsy can also cause double vision. It controls several eye muscles and the levator palpebrae superioris, which elevates the eyelid. However, it often presents with ptosis (drooping eyelid) and pupil dilation on the affected side, which are not mentioned in the scenario.
- Sixth Cranial Nerve (Abducens Nerve) Palsy: This condition affects the lateral rectus muscle, leading to inability to abduct the eye and resulting in double vision. Like third nerve palsy, it can be caused by increased intracranial pressure, microvascular ischemia, or other conditions.
- Orbital Myasthenia Gravis: A condition characterized by fluctuating muscle weakness that can affect the extraocular muscles, leading to double vision. Symptoms can worsen with fatigue and improve with rest.
Do Not Miss Diagnoses
- Giant Cell Arteritis: Although less likely given the absence of other symptoms like headache, jaw claudication, or visual loss, giant cell arteritis is a critical diagnosis not to miss due to its potential for causing irreversible vision loss if not promptly treated.
- Diabetic Ophthalmoplegia: Diabetes can cause cranial nerve palsies, including third, fourth, and sixth nerve palsies, which can present with sudden onset double vision.
- Brainstem or Cerebellar Stroke: A stroke in the brainstem or cerebellum can cause double vision due to involvement of the cranial nerve nuclei or their pathways. This is a medical emergency requiring immediate attention.
Rare Diagnoses
- Wernicke's Encephalopathy: A condition caused by thiamine deficiency, often seen in alcoholics, which can present with ophthalmoplegia (weakness or paralysis of one or more extraocular muscles), among other symptoms.
- Tolosa-Hunt Syndrome: A rare condition characterized by painful ophthalmoplegia due to inflammation of the cavernous sinus or superior orbital fissure, which can cause double vision.
- Thyroid Eye Disease: Although typically associated with proptosis, eyelid retraction, and periorbital swelling, thyroid eye disease can occasionally cause diplopia due to restrictive myopathy of the extraocular muscles.