Differential Diagnosis for Acute Onset Internal Right Strabismus
Single Most Likely Diagnosis
- Sixth Cranial Nerve Palsy (Abducens Nerve Palsy): This is the most likely diagnosis due to the acute onset of internal strabismus, which is often caused by a problem with the abducens nerve that controls the lateral rectus muscle responsible for outward eye movement.
Other Likely Diagnoses
- Third Cranial Nerve Palsy (Oculomotor Nerve Palsy): Although less common than sixth nerve palsy for causing isolated strabismus, third nerve palsy can lead to inward deviation of the eye (esotropia) among other symptoms, due to its control over several extraocular muscles.
- Thyroid Eye Disease: This condition can cause inflammation and swelling of the tissues around the eye, including the extraocular muscles, leading to strabismus. It's a common cause of acquired strabismus in adults.
- Orbital Myositis: Inflammation of one or more of the extraocular muscles can cause strabismus, and while less common, it should be considered, especially if there's a history of recent infection or autoimmune disease.
Do Not Miss Diagnoses
- Stroke or Cerebral Vasculitis: Although less likely, these conditions can cause cranial nerve palsies, including sixth nerve palsy, and are critical to diagnose promptly due to their potential for severe morbidity and mortality.
- Increased Intracranial Pressure: Conditions like idiopathic intracranial hypertension can cause sixth nerve palsy due to increased pressure on the nerve. Early diagnosis is crucial to prevent complications.
- Tumor (e.g., Brainstem Glioma, Pituitary Adenoma): Tumors in certain locations can compress cranial nerves, leading to strabismus. These are potentially life-threatening and require urgent diagnosis.
Rare Diagnoses
- Graves' Disease with Restrictive Strabismus: While more commonly associated with proptosis and eyelid retraction, in rare cases, Graves' disease can cause restrictive strabismus due to fibrosis of the extraocular muscles.
- Congenital or Acquired Brown Syndrome: A condition affecting the superior oblique tendon, leading to limited upward gaze and potentially esotropia in certain gaze positions.
- Myasthenia Gravis: An autoimmune disease that can cause fluctuating muscle weakness, including the extraocular muscles, leading to strabismus that may vary in severity throughout the day.