Hypertonisia

Hypertonisia is a term sometimes used to describe hypertonia, a neurological condition in which there is abnormally increased muscle tone. It is not a single disease but a syndrome that can arise from various disorders affecting the central nervous system. Clinically, hypertonisia includes several phenotypes with distinct mechanisms: spasticity, dystonia, and rigidity.

Spasticity is the most characteristic form in many patients and is generally velocity-dependent, meaning resistance to passive movement increases with the speed of the stretch. Dystonia involves sustained or intermittent muscle contractions that produce abnormal postures or repetitive movements. Rigidity refers to a constant resistance to movement that is not dependent on velocity, often seen in Parkinsonian disorders. These phenotypes can overlap in the same individual.

Common causes include upper motor neuron lesions from stroke, traumatic brain injury, cerebral palsy, and multiple sclerosis, as well as spinal cord injury and neurodegenerative or metabolic diseases. The underlying pathology typically involves disrupted balance between excitatory and inhibitory signals in motor pathways, changes in muscle properties, and altered spinal reflexes.

Diagnosis relies on clinical examination, supported by standardized scales such as the Modified Ashworth Scale or Tardieu scale to assess spasticity. Neuroimaging and electrophysiological studies help identify lesion location and guide treatment, but hypertonia itself is diagnosed from the clinical presentation and history.

Management requires a multidisciplinary approach focused on functional goals. Therapies include physical and occupational therapy, stretching, orthotics, and positioning. Pharmacologic options include oral antispastic agents (baclofen, tizanidine, diazepam, dantrolene), botulinum toxin injections for focal spasticity, and intrathecal baclofen when necessary. Surgical interventions such as selective dorsal rhizotomy or deep brain stimulation may be considered in select cases. Prognosis varies with the underlying condition and response to therapy.