Do you blink a lot? It can be a sign of an illness

Do you feel like you are blinking excessively lately? Maybe it’s a sign of cranial focal dystonia… What is that? Here we explain:

Benign essential blepharospasm (BEB) is a focal cranial dystonia, characterized by excessive and involuntary contractions of the eyelid muscles, which is usually bilateral (although it can be unilateral at the onset of symptoms)1. BEB can be considered a disabling disease due to the progression of symptoms that can lead to functional blindness, reducing quality of life and psychological functioning(1).

Dr. Salvador José Santamaría Molina, Clinical Neurologist in charge of the Abnormal Movements and Botulinum Toxin Application Clinic of the Specialty Hospital of the La Raza National Medical Center, mentioned that due to the constant and involuntary closing of the eyelids, patients resort to tricks sensory to try to open your eyes. Examples of these are the use of bands around the forehead or touching the orbicularis muscles of said region, which become inefficient as the condition progresses.

Initial symptoms of blepharospasm include unpleasant sensations, fluttering of the eyelids or increased blinking frequency to stimuli, which progress to chronic, bilateral, involuntary eye twitches. It may be accompanied by other dystonic movements in some patients, including progression of the eyebrow, paranasal, labial, masticatory, lingual, pharyngeal and cervical muscles, which is when the condition is known as cranial or craniocervical dystonia(1).

Blepharospasm is a very rare condition. Current studies have shown that the prevalence range of blepharospasm is from 16 to 133 per million individuals1. Likewise, studies show that the highest prevalence is observed in women and older adults1. In this context, Dr. Santamaría added that the condition usually occurs around the seventh decade of life (60-70 years of age), however, there are no statistics in Mexico, due to the low incidence and the difficulty of diagnosis.

Likewise, the specialist clarified that blepharospasm is often confused with a “tic”; The differences between both conditions is that the “tic” affects younger people and is very variable in the way it presents, that is, it can affect different parts of the body such as the face, neck and extremities; while blepharospasm is a focal phenomenon, limited exclusively to the orbicularis muscles with a repetitive, sustained and almost uncontrollable movement.

Regarding the control of the condition, Dr. Santamaría highlighted that the most accessible therapy is the application of Botulinum Toxin type A 500U, the extract of a bacteria that is injected into the orbicularis muscles of the eyelids and that acts by blocking the nerve terminal towards the muscle, which generates muscle weakness; This allows the blinking to decrease and acquire a normal function, with this the patient will literally be able to open their eyes. The durability of the clinically proven treatment is up to 5 months (2).

The specialist stated that an advantage of the 500U toxin with respect to other toxins is that it presents a profile with a higher level of potency, that is, with a smaller number of units, more sustained therapeutic benefits could be obtained in the patient, which It represents a cost benefit for the applicator and therefore for the patient. He added that some oral medications are also used, but most do not provide real benefit. Another option is myomectomy, a surgery that involves cutting small fragments of the contracted muscle to try to weaken it, however, it is also not usually successful.

“Most of the time blepharospasm is considered an idiopathic condition (there is no well-defined cause), however, there is a relationship with certain eye diseases, such as: dry eye syndrome, eye trauma or some injury to the eye. the cornea, to name a few. The diagnosis is based on the clinical and movement evaluation, its characteristics, affected sites, frequency, factors that attenuate them and added studies to investigate if there is another possible alteration that explains said anomaly; The specialists involved in it are Neurologists and Ophthalmologists” concluded Dr. Santamaría.

References

1. Truong D, Comella C, Fernandez H, Ondo W. Efficacy and safety of purified botulinium toxin type A (Dysport®) for the treatment of bening essential blepharospasm: a randomized placebo-controlled, phase II trial. Parkinsonism and related disorders 14, 2008: 407-414.

2. Jitpimolmard S et al. Long term results of botulinum toxin type A (Dysport®) in the treatment of hemifacial spasm: a report of 175 cases. J Neurol Neurosurg Psychiatry 1998;64:751-757.

3. www.ipsen.com