Hemifacial spasm

Hemifacial Spasm (Facial Twitch)

Hemifacial Spasm of right side of face. Right eye twitching & right corner of mouth raised upwards. Patient was treated with Botox Injections to the right eyelid & right side of face.

General overview:

Hemifacial spasm is a condition in which there is reflexive or involuntary twitching or contracting movements of the muscles of the face on one side (hemi/half) of the face. Hence, it is also referred to as “facial twitch”. These twitching movements are irregular and almost always limited to one side of the face as the name suggests. Hemifacial spasm (HFS) is a rare neuromuscular condition. The muscles of the face are controlled/monitored by the seventh cranial nerve (facial nerve) which arises from the brainstem and leaves the skull below the ear where it gives out five main branches.

Hemifacial Spasm has two forms:

• © Typical – This is the most commonly occurring form of twitching in individuals affected with HemiFacial Spasm. Twitching movements generally begin in the lower eyelid in the orbicularis oculi muscle. As time advances, it involves the whole eyelid, then to the orbicularis oris muscle around the lips (mouth), and buccinator muscle in the cheekbone area in the lower face.
• © Atypical – In this form, the reverse process takes place. Twitching begins in the orbicularis oris muscle around the lips (mouth), and buccinator muscle in the cheekbone area in the lower face, then extends up to the orbicularis oculi muscle in the eyelid as time advances. This form of twitching is observed in about 2-3% of patients with HemiFacial Spasm.

Epidemiology:

• HFS is most likely to occur in Asian population.
• No particular preponderance for sex. It occurs in both, men and women. However, it is most likely to affect the individuals who middle-aged or elderly, particularly women.

Symptoms:

• Reflexive/involuntary movement of the face is the only symptom of HFS.
• Anxiety, fatigue or reading may trigger the movements.
• Twitching is generally not painful, but may be embarrassing and may intervene with normal expression and vision.

Causes:

• The major cause being compression of the facial nerve, which could be as a result of a tumor pressing on to the nerve, a blood vessel compressing the nerve, injury to the facial nerve, or Bell’s Palsy.
• The most typical cause is compression of the facial nerve by the anterior inferior cerebellar artery, where the nerve starts at the brainstem. Because of compression, there is failure of muscles to contract. This condition is also referred to as “Trigeminal neuralgia” – an irritation of the 5^th cranial nerve that leads to severe facial pain. Both hemifacial spasm and trigeminal neuralgia are produced due to nerve compression from a blood vessel, yet differ in whether the sensory or the motor nerve is compressed.

How is the diagnosis of Hemifacial Spasm made?

Patient’s clinical history should be taken and neurological examination is performed. An MRI scan may be carried out to eliminate certain other causes like brain tumor, aneurysm or any other factor leading to compression of facial nerve. Also, an EMG (electromyogram) may be ordered to study the face along with NCV (nerve conduction velocity) study for the measurement of electrical activity of the nerve and muscle.

Treatment:

• Medical therapy for hemifacial spasm – Anti-convulsant drugs such as carbamazepine or phenytoin in order to block the nerve from firing. Muscle relaxants such as diazepam, clonazepam, baclofen may be prescribed. These drugs may produce certain side-effects like nausea, drowsiness, skin rash, unsteadiness, dependence. Hence, patients are assessed routinely and asked to undergo blood tests to make sure that the drug levels remain safe and patient do not develop blood disorders.
• Microvascular decompression(surgical therapy for hemifacial spasm) – Microvascular decompressionproves to be the most popular surgical treatment at present. Microvascular compression relieves pressure on the facial nerve, which is the cause of most hemifacial spasm cases. Excellent to good results are reported in 80% or more cases, with a 10% recurrence rate. Serious complications (side effects) can follow microsurgical decompressive operations, even when performed by experienced surgeons. These include cerebellar haematoma or swelling, brain stem infarction (blood vessel of the brain stem blocked), cerebral infarction (ischemic stroke resulting from a disturbance in the blood vessels supplying blood to the brain),subdural haematoma and intracerebral infarction (blockage of blood flow to the brain). Death or permanent disability (hearing loss) can occur in 2% of patients of hemifacial spasm, treated by surgical methods.
• Botulinum Toxin (Botox) treatment of Hemifacial Spasm– Botulinum toxin, or Botox, is a protein produced by the C. botulinum bacteria that leads to muscle paralysis by blocking the electrical messages that “tell” the muscle to move. Messages are conveyed by a neurotransmitter called acetycholine. Botox hinders the release of acetycholine; due to which, the muscle doesn’t receive the message to contract. A very fine needle is used to deliver 1 to 3 injections into your facial muscles. Botox usually works within three days and usually lasts for three months. Botox injections for hemifacial spasm can be repeated indefinitely, however the effectiveness diminishes over the years due to the buildup of antibodies. Side effects of Botox Injections include temporary facial weakness, drooping eyelid, eye irritation and sensitivity. To avoid Botox complications, injections to the eyelid area must be given by well trained, best facial plastic surgeons.