A 26-year-old woman comes to the office due to eye problems. One week ago while driving, her eyes closed spontaneously after she looked at the headlights of an oncoming car. She briefly could not open her eyes and had to stop driving until the symptoms gradually improved over several minutes. Since then, she has had 3 similar episodes brought on by bright light exposure. The patient has had no fever, eye pain or discharge, blurry or double vision, headaches, or extremity weakness or numbness. She has a history of asymptomatic sarcoidosis and takes no medications. Vital signs are within normal limits. On physical examination, there is no facial asymmetry. Frequent blinking of the eyes is noted, and shining light in the eyes to assess pupillary response causes involuntary tonic closure of the eyelids bilaterally. The remainder of the examination is normal. Which of the following is the most likely diagnosis?
This patient has recurrent forceful contraction of the eyelid muscles consistent with blepharospasm, a form of focal dystonia. Blepharospasm is usually bilateral and symmetric. When associated with spasm of the lower face (eg, jaw, tongue), it is termed Meige syndrome. Blepharospasm is commonly affected by sensory input; bright lights may trigger the muscle contraction, whereas touching or brushing the skin around the eye may terminate the spasm ("sensory trick").
Blepharospasm can be caused by certain movement disorders (eg, Parkinson disease) or medications (eg, antipsychotics), but most cases are idiopathic (ie, benign essential blepharospasm). It should be differentiated from simple eyelid twitching, which causes fleeting, minor lid contractions that are unilateral and do not affect vision. Mild cases may be managed with trigger avoidance, such as wearing dark glasses to block bright lights, but botulinum toxin injection may be needed for more significant symptoms.
(Choice A) Acute uveitis is characterized by inflammation of the iris and ciliary body and is a common ocular manifestation of sarcoidosis. Although it may cause sensitivity to light (with voluntary closure of the lids), it typically presents with ocular pain; examination shows pupillary constriction and redness at the limbus (ciliary flush).
(Choices C and D) Myasthenia gravis is characterized by fluctuating, fatigable muscle weakness that is often worse at the end of the day. It is occasionally limited to the extraocular muscles, where it presents with diplopia (oculomotor paresis) and ptosis. Myotonic dystrophy is an autosomal dominant disorder that causes weakness and delayed relaxation of muscle; involvement of the facial muscles may lead to ophthalmoparesis. Examination in these disorders would show muscular weakness rather than blinking or blepharospasm.
(Choice E) Trigeminal neuralgia can cause facial muscle spasm (tic douloureux), but the most prominent feature is paroxysmal, severe, shooting or burning pain in a dermatomal distribution following the trigeminal nerve (cranial nerve V).
Educational objective:
Blepharospasm is a form of focal dystonia characterized by recurrent forceful contraction of the eyelid muscles. Bright lights may trigger symptoms, whereas touching or brushing the skin around the eye may terminate the spasm (ie, "sensory trick").