When Eye Twitching Means More: Unmasking Hemifacial Spasm

Kritika Gautam, B.Optom

Optometrist, Dr Shroff’s Charity Eye Hospital, New Delhi, India

 

Eye twitching is frequently brought on by stress, eye strain, and fatigue, particularly in relation to the muscles and nerves in the face. These twitches are temporary that last for some time and resolve on their own without any medical intervention. However, persistent, and severe twitching indicates underlying conditions that can be misdiagnosed with regular twitches. One such condition is Hemifacial Spasm.

Involuntary unilateral contractions of the ipsilateral facial nerve- innervated muscles, which typically begin around the eyes and move inferiorly to the cheek, mouth, and neck, are the hallmark of Hemifacial Spasm (HFS)⁽¹⁾ 9.8 out of every 100,000 people with average age of onset of 44 years have HFS.⁽¹⁾

Pathophysiology:

According to the recognized underlying pathophysiology of HFS, the disease process is brought on by myelin breakdown in the facial nerve root entry zone and ephaptic transmission, which is the transmission of neural impulses through synthetic or chemical synapses.⁽¹⁾

Aetiology:

Primarily HFS results from the compression of facial nerve by the native nerve. Secondary causes of facial nerve damage can be trauma, tumour, bell’s palsy, demyelination, and stroke.⁽¹⁾

Clinical features-

The orbicularis oculi muscle contracts at the onset of HFS, causing involuntary eyelid closure and eyebrow elevation. The frontalis (the muscles of the forehead), platysma (the muscles of the neck), and orbicularis oculi (the muscles of the mouth) muscles are eventually affected by the contractions. At some point, the patient may experience prolonged contractions of every muscle involved, resulting in a severe, disfiguring phenomenon known as the “tonus phenomenon,” which also involves the lifting of the corners of the mouth and partial closure of the eyes.⁽¹⁾

The majority of HFS cases occur unilaterally with an estimated 0.6% to 5% occurring bilaterally. ⁽²⁾

Certain patients may experience exacerbation of spasms in response to exhaustion, anxiety, or head posture changes.⁽¹⁾ Study discovered that headaches connected to HFS were linked to more severe spasms. Findings show that 40% of people with HFS also have hypertension at the same time. Determining if the patient has hypertension is therefore crucial.⁽³⁾

Diagnosis:

To diagnose and evaluate HFS, just two tests are needed: electroneuromyography (ENMG) to identify the specific type of nerve excitability issue and magnetic resonance imaging (MRI) to show the neurovascular conflict.⁽⁴⁾

Treatment:

Injections of botulinum neurotoxin, which offer minimal but risk-free symptomatic relief, are the usual medical care for HFS. Microvascular decompression (MVD), a surgical procedure that lessens compression of the facial nerve root to give long-lasting symptomatic relief, is the only treatment that may be considered curative for HFS.

The diagnosis of HFS is frequently delayed, necessitating the involvement of specialists who are primarily concerned with the management of movement disorders.

 

References:

1. Lu AY, Yeung JT, Gerrard JL, Michaelides EM, Sekula Jr RF, Bulsara KR. Hemifacial spasm and neurovascular compression. The scientific world journal. 2014;2014(1):349319.
2. Chopade, T.R. and Bollu, P.C., 2018. Hemifacial spasm.
3. Ghali MG, Srinivasan VM, Viswanathan A. Microvascular decompression for hemifacial spasm. International Ophthalmology Clinics. 2018 Jan 1;58(1):111-21.
4. Lefaucheur JP. New insights into the pathophysiology of primary hemifacial spasm. Neurochirurgie. 2018 May 1;64(2):87-93.