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superior_oblique_myokymia [2015/06/29 01:38] – created adminsuperior_oblique_myokymia [2025/04/18 20:40] (current) – external edit 127.0.0.1
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 +====== Superior Oblique Myokymia ======
  
 +===== Definition =====
 +Uniocular paroxysms of small-amplitude, high-frequency rotary nystagmus.
 +
 +===== Etiology =====
 +  * Unknown. 
 +  * May be regeneration of damage to trochlear nerve as it has been described in two patients who had superior oblique palsy. [[http://archopht.ama-assn.org/cgi/reprint/102/8/1178|Arch Ophth Link]]
 +  * If there are other neurological symptoms there could be a tumor compressing the midbrain.
 +
 +===== Clinical Features =====
 +=== Patient History ===
 + 
 +  * Intermittent bursts of torsional and/or vertical diplopia or "shimmering" vision.
 +  * Episodes last several seconds to several minutes
 +  * Fatigue and stress may exacerbate 
 +=== Exam ===
 +
 +  * Rapid small-amplitude torsional eye movement, may only be seen at the slit lamp
 +  * Normal eye movements in absence of symptoms
 +===== Work Up =====
 +None unless other neurologic signs then consider neuroimaging
 +===== Treatment =====
 +None if the patient is not bothered
 +=== Medical Treatment ===
 +  * topical betaxolol (Betoptic 0.5%, Betoptic S 0.25%) BID- one report of success
 +  * [[carbamazepine|carbamazepine]] (tegretol) 100 mg BID or TID to start and move to up to 200 mg TID as needed
 +    * potential side effects including leucopenia, acute renal failure, thromboembolism, and arrhythmias
 +    * blood counts (CBC, including platelets and reticulocytes), serum iron, liver function and renal function (urinalysis an BUN) needed to be monitored regularly 
 +  * [[gabapentin|gabapentin]] 100mg QD or BID can titrate up to 300mg PO BID  
 +  * [[propranolol|propranolol]] 80 mg long acting
 +  * phenytoin (dilantin) 100mg PO TID
 +  * propranolol plus valproic acid
 +  * Medical treatment is often disappointing and fraught with side effects
 +
 +=== Surgical Treatment ===
 +  * Tenectomy of Superior Oblique- a large portion needs to be removed
 +  * Combine above with prophylactic inferior oblique weakening
 +  * Some require a second surgery to treat residual diplopia with recession of contralateral inferior rectus with a nasal shift and possibly a nasal shift of both inferior rectus muscles if there is excyclotorsion
 +
 +{{tag>strabismus}}