Introduction

Spasticity is defined clinically as ‘a motor disorder characterised by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon acts resulting from hyperexcitability of the stretch reflex, as one component of the upper motor neuron syndrome’.1 Spasticity is a common feature of cerebral palsy (CP) as well as spinal cord and traumatic brain injury.

The most common cause of spasticity in childhood is CP which affects between 2 and 3 of every 1000 live births in industrialised countries.2 Other causes of spasticity include traumatic brain injury, spinal cord injury, central nervous system tumour or infarct, metabolic disorders and hydrocephalus.

Dystonia is defined as ‘a movement disorder in which involuntary sustained or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures or both’.3 Dystonia may be either acute (eg, an oculogyric crisis secondary to drug administration) or chronic. Chronic dystonia can occur either locally (eg, writer's cramp, blepharospasm) or systemically as part of CP or other neurological syndromes.

The management of spasticity and chronic dystonia in children requires multidisciplinary management including neurologists, paediatricians, surgeons, GPs, physiotherapists, occupational therapists and pharmacists. Pharmacotherapy forms one aspect of this management and will be the focus of this review article, but other interventions, such as physical therapy, orthopaedic surgery and procedures, such as selective dorsal rhizotomy, play a major role too. Fundamental knowledge of pharmacologic properties and toxicities of these medications is required for safe and appropriate use, and should be part of an integrated therapeutic approach in which patients, carers, therapists, physicians and surgeons have open and clear communication about the overall rehabilitation process of the patient.