Botulinum toxin A (BTX-A) is widely used worldwide to overcome the significant problem in spastic cerebral palsy (CP). In the past three decades, botulinum toxin serotype A (BTX-A) has been introduced as a selective treatment option for spasticity in children with cerebral palsy. BTX-A is an acetylcholine-blocking agent that causes presynaptic neuromuscular blocking when injected into the muscle. Its action of decreasing or normalization of tone prevent the development of contractures and deformities and avoid or postponed surgical intervention particularly when combined with other treatment modalities such as physiotherapy, casting, orthosis, etc. Equinus deformity, scissoring and crouch gait in the lower limbs, and different spastic deformities like pronation of forearm, elbow flexion, wrist flexion, fisting, or abnormal dystonic posture of upper limb deformities were the main indications wherein botulinum toxin injection is needed in spastic cerebral palsy; moreover, its benefit of relieving pain that are associated with muscular hypertonia and palpation of the muscle, particularly the large one, remains the cornerstone for injection of BTX in CP patient for most experts worldwide, but it needs a well of knowledge in anatomy and its landmark. Invasive procedure like electromyography (EMG) is more difficult to be applied successfully in children than in adults. Spasticity is considered a positive phase of muscle function. Therefore, when relaxing the muscle, the patient’s condition might get worse functionally in some instance. So, the first question clinician put in his account before injecting BTX is whether hypertonia is impeding or improving function; therefore, injection is tailored individually by an expert physician. Generally, the adverse side effects of BTX-A are seldom to occur providing that the physician strictly adheres to the dose ranges and reinjection period. The inter-injection period must be at least 12 weeks to avoid antibodies ands. So far, BTX-A is considered to be safe to some extent if used professionally; however, long-term adverse effect particularly with multilevel therapy are still not clear.
Part of the book: Cerebral Palsy
The myasthenic syndrome in children can be inherited or of acquired autoimmune origin. In the autoimmune syndrome, babies born to a myasthenic mother are floppy at birth with weak cry, ptosis, and impaired respiration. Fortunately, most of these cases are transient and complete recovery will take place after few weeks; however, good supportive measures are needed until recovery. On the other hand, the classical autoimmune myasthenia gravis (MG), which is known as juvenile myasthenia gravis, can occur in children of any age group. It is commonly divided into prepubertal and postpubertal, the latter usually follows adult criteria, is more common in females, generalized, and most of them are seropositive for neuromuscular antibodies. In contrast, in acquired myasthenia gravis that occurs in prepubertal children, there is no sex predilection and patients are less likely seropositive, and ocular myasthenia more likely to occur than postpubertal. An interesting group of childhood myasthenic syndromes is the congenital myasthenic syndrome; this is an uncommon, nonimmune-mediated heterogeneous syndrome with variable presentation, ranging from mild symptoms with little weakness to severe ones that may cause extreme weakness and respiratory failure. Congenital myasthenic syndrome is classified into presynaptic, synaptic, and postsynaptic, and each of them has subtypes, with the postsynaptic syndrome representing the most common type. Many patients with congenital myasthenic syndrome are misdiagnosed with seronegative acquired myasthenia or congenital myopathy; however, advances in disease investigation are showing promise in early and precise diagnosis.
Part of the book: Selected Topics in Myasthenia Gravis