Paralysis, or PALSY, is loss of muscular power due to some disorder of the NERVOUS SYSTEM. Weakness – rather than total movement loss – is sometimes described as paresis. Paralysis may be temporary or permanent and may be accompanied by loss of feeling.
The most common form is palsy of one side of the body – HEMIPLEGIA, generally arising from cerebral HAEMORRHAGE, THROMBOSIS or EMBOLISM affecting the opposite side of the BRAIN. If all four limbs and trunk are affected, the paralysis is called quadriplegia; a particular form in very premature babies involves all limbs affected but the legs much more so than the arms; this is termed diplegia. If both legs and part of the trunk are affected, it is called paraplegia. Paralysis may also be divided into flaccid (floppy limbs) or spastic (rigid).
Brain and spinal cord, showing motor paths and positions of injuries causing various forms of paralysis.
Causes include brain abscess, haemorrhage, thrombosis or TUMOUR, CEREBRAL PALSY and ENCEPHALITIS. Sometimes damage occurs in the parts of the nervous system responsiblefor the fine control of muscle movements: the cerebellum and basal ganglion are such areas, and lack of DOPAMINE in the latter causes PARKINSONISM.
Damage to or pressure on the SPINAL CORD may paralyse muscles supplied by nerves below the site of damage. A fractured spine or pressure from a tumour may have this effect. Disorders affecting the cord which can cause paralysis include osteoarthritis of the cervical vertebrae (see BONE, DISORDERS OF), MULTIPLE SCLEROSIS (MS), MYELITIS, POLIOMYELITIS and MENINGITIS. Vitamin B12 deficiency (see APPENDIX 5: VITAMINS) may also cause deterioration in the spinal cord (see also SPINE AND SPINAL CORD, DISEASES AND INJURIES OF).
are a group of disorders, some inherited, that damage the peripheral nerves, thus affecting their ability to conduct electrical impulses. This, in turn, causes muscle weakness or paralysis. Among the causes of neuropathies are cancers, DIABETES MELLITUS, liver disease, and the toxic consequences of some drugs or metals – lead being one example.
themselves – for example, muscular dystrophy (see MUSCLES, DISORDERS OF – Myopathy) – can disturb their normal working and so cause partial or complete paralysis of the part(s) affected.
The aim of treatment should be to remedy the underlying cause – for example, surgical removal of a displaced intervertebral disc or treating diabetes mellitus. Sometimes the cause cannot be rectified but, whether treatable or not, physiotherapy is essential to prevent joints from seizing up and to try to maintain some tone in muscles that may be only partly affected. With temporary paralysis, such as can occur after a STROKE, physiotherapy can retrain the sufferers to use their muscles and joints to ensure mobility during and after recovery. Patients with permanent hemiplegia, paraplegia or quadriplegia need highly skilled nursing care, rehabilitative support and resources, and expert help to allow them, if possible, to live at home.