The neurology franchise, which capitalizes on botulinum toxin type a, covers a large spectrum of indications such as dystonia and spasticity.
Dystonia is a motor disorder characterized by involuntary and sustained muscle contractions resulting in abnormal positions, always identical in the same patient.
Blepharospasm is an involuntary contraction of the muscles located around the eyes, causing the eyelids to close intermittently or for prolonged periods of time. It starts with involuntary blinking, which then becomes increasingly frequent, and, after several weeks, leads to spasms with full closure of the eyelids lasting from a few seconds to several minutes. Blepharospasm may lead to a functional blindness representing a major handicap for the patient.
Cervical dystonia is characterized by intermittent spasms of the neck muscles, causing a head tilt. This condition is painful and impairs social life with task specific limitation (e.g., inability to drive).
Hemifacial spasm is a contraction of the muscles located on one side of the face. In its least severe form, hemifacial spasm causes only a mild discomfort. However, it can become very unsightly and affect the patient's social life. In the most serious cases, uncontrolled eyelid closure may impair vision. However, as only one eye is affected, hemifacial spasm is not associated with total vision loss.
Spasticity is more or less a marked tendency of muscles to contract.
Spasticity is observed in most people with certain types of lesions of the central nervous system. It is characterized by an abnormal increase in muscle tone with rigidity and exaggeration of the tendon reflexes.
Brain damage may cause lower limb spasticity leading to equinus foot deformity. Equinus foot deformity is due to a contraction of the calf muscles which may result in an inability to perform a dorsiflexion of the foot and toes. The normal gait is replaced by a gait on tiptoes. This anomaly affects the balance with abnormal pressure on the ankle. This deformity is said to be dynamic when the muscle can still be stretched (the presence of fibrosis may prevent such stretching).