Blepharospasm

✍️ Large variation in prevalence, ranging from 16 to 133 per million in different studies.

✍️ an autosomal dominant disorder with reduced penetrance of about 5%.

✍️ Age and female gender may increase the risk of developing benign essential blepharospasm.

✍️ No association was found with age-related medical conditions such as hypertension and diabetes, family history of Parkinson, anxiety or depression.

✍️ normal blinking involves the activity of the orbicularis oculi,corrugator superciliaris and procerus muscles to close the eyelids and the co-inhibition of the retractors of the eyelids (levator palpebral superioris and the frontalis mucles).

✍️ In blepharospasm, the inhibition between the protractors and the retractors is lost.

✍️ The involved location can be anywhere along the neurological pathway controlling eye blinking, starting from the sensory pathway, to the central control centers located in the midbrain, to the motor pathway.

✍️ The sensory limb is triggered by light, corneal or eyelid irritation, pain, emotion, stress, or other trigeminal stimulants.

✍️ The central control center can be weakened by injury, genetic predisposition, or age, which results in abnormality in the feedback circuit.

✍️ The motor pathway comprises of the facial nucleus, facial nerve, orbicularis oculi muscle, corrugators, procerus muscles, and other facial muscles may be involved.

✅Blepharospasm Clinical picture

✍️ Symptoms:

☝️ Initially increased blinking rate
☝️ eyelid spasms in response to common stimuli. ☝️ ocular surface irritation
☝️ foreign body sensation
☝️ symptoms of dry eye
☝️ painful photophobia
☝️ midfacial or lower facial spasm
☝️ brow spasm, or eyelid tic.
☝️ involuntary unilateral then bilateral eyelid
☝️ Severe presentation may include complaints of inability to watch television, read, write, drive and decreased vision( functional blindness)
☝️ history of dystonic movements of other facial muscles.
☝️ Conditions relieving spasm include sleep, relaxation, inferior gaze, artificial tears, traction, talking, singing, and humming.

✍️ Signs:

☝️ Involuntary spasms, blinking, and/or tics of the eyelids.
☝️ eyelid and brow ptosis
☝️ dermatochalasis, entropion
☝️ canthal tendon abnormalities with long standing blepharospasm.

✅ Blepharospasm DD

✍️ Bell’s palsy
✍️ allergic conjunctivitis
✍️ eyelid myokymia
✍️ Meige syndrome
✍️ oromandibular dystonia
✍️ spasmodic toricollis
✍️ uveitis.

✅Blepharospasm Managing

✍️ Complete eye exam assessing for presence of ocular surface disease or foreign bodies.

✍️ No laboratory studies are required for diagnosis.

✍️ MRI of posterior cranial fossa may be considered for hemifacial spasm.

✍️ Address the sensory pathway of the blepharospasm circuit by recommending wear of tinted sunglasses with UV blocking to decrease the poorly understood associated photophobia.

✍️ Lid hygiene to decrease irritation and blepharitis with frequent use of artificial clears to relieve dry eye symptoms.

✍️ Botulinum A toxin injection is the most effective treatment of choice.

☝️ The toxin is produced by Clostridium botulinum

☝️ interferes with acetylcholine release from nerve terminals causing temporary paralysis of the associated muscles.

☝️ The peak effect occurs 5-7 days after injection, with a mean lasting effect of 3 months, but duration of efficacy ranges from 1-5 months.

☝️ Complications include

• ptosis
• lagophthalmos
• symptomatic dry eye
• entropion, ectropion
• epiphora, photophobia
• diplopia
• ecchymosis
• lower facial weakness.

☝️ Botulinum A toxin should be hydrated with 0.9% non-preserved saline, without shaking the vial to prevent frothing

☝️ should be used within a few hours or refrigerated once reconstituted.

☝️ Use of a total dose of no more than 25 units per eye, divided among 4-6 periocular injection sites to avoid adverse effects.

☝️ Inject 2.5-10 units of botulinium A toxin at each site, subcutaneously over the orbicularis oculi muscle, intramuscularly over the thicker corrugators and procerus muscles.

✍️ Antidepressants are useful to indirectly help if depression exacerbate blepharospasms.

☝️ Pharmacotherapy for facial dystonias and blepharospasm are based on targeting cholinergic excess, GABA hypofunciton, and dopamine excess.

☝️ Pharmacotherapy is generally less effective than botulinum injection and usually reserved as second line treatment for spasms poorly responsive to botulinum injection or for cases with midface and lower face spasms involvement.

☝️ The relief provided is variable.

✍️ Patients who do not achieve improvement with botulinum injections may require myectomy of orbicularis oculi.

☝️ NB

✍️ Treatment with botulinum A toxin is usually temporary as most patients require repeat treatment every 3 months, but the duration can range between 1-5 months. Thus, long term follow-up care is needed.