paralysis
[pah-ral´ĭ-sis] (pl. paral´yses.) Loss or impairment of motor function in a part due to a lesion of the neural or muscular mechanism; also, by analogy, impairment of sensory function (
sensory paralysis). Paralysis is a symptom of a wide variety of physical and emotional disorders rather than a disease in itself. Called also
palsy.
Types of Paralysis. Paralysis results from damage to parts of the nervous system. The kind of paralysis resulting, and the degree, depend on whether the damage is to the central nervous system or the peripheral nervous system.
If the central nervous system is damaged, paralysis frequently affects the movement of a limb as a whole, not the individual muscles. The more common forms of central paralysis are
hemiplegia (in which one entire side of the body is affected, including the face, arm, and leg) and
paraplegia (in which both legs and sometimes the trunk are affected). In
central paralysis the tone of the muscles is increased, causing
spasticity.
If the peripheral nervous system is damaged, individual muscles or groups of muscles in a particular part of the body, rather than a whole limb, are more likely to be affected. The muscles are flaccid, and there is often impairment of sensation.
Causes of Central Paralysis.
stroke syndrome is one of the most common causes of central paralysis. Although there is usually some permanent disability, much can be done to rehabilitate the patient. Paralysis produced by damage to the spinal cord can be the result of direct injuries, tumors, and infectious diseases. Paralysis in children may be a result of failure of the brain to develop properly in intrauterine life or of injuries to the brain, as in the case of
cerebral palsy. Congenital
syphilis may also leave a child partially paralyzed. Paralysis resulting from
hysteria has no organic basis and is a result of emotional disturbance or mental illness.
Causes of Peripheral Paralysis. Until the recent development of immunizing vaccines, the most frequent cause of peripheral paralysis in children was
poliomyelitis.
neuritis, inflammation of a nerve, can also produce paralysis. Causes can be physical, as with cold or injury; chemical, as in lead poisoning; or disease states, such as diabetes mellitus or infection. Paralysis caused by neuritis frequently disappears when the disorder causing it is corrected.
paralysis of accommodation paralysis of the ciliary muscles of the eye so as to prevent
accommodation.
ascending paralysis spinal paralysis that progresses upward.
birth paralysis that due to injury received at birth.
brachial paralysis paralysis of an upper limb from damage to the
brachial plexus.
bulbar paralysis that due to changes in motor centers of the medulla oblongata; the chronic form is marked by progressive paralysis and atrophy of the lips, tongue, pharynx, and larynx, and is due to degeneration of the nerve nuclei of the floor of the fourth ventricle.
central paralysis any paralysis due to a lesion of the brain or spinal cord.
cerebral paralysis paralysis caused by an intracranial lesion; see also
cerebral palsy.
compression paralysis that caused by pressure on a nerve.
conjugate paralysis loss of ability to perform some parallel ocular movements.
crossed paralysis paralysis affecting one side of the face and the other side of the body.
crutch paralysis brachial paralysis caused by pressure from a crutch.
decubitus paralysis paralysis due to pressure on a nerve from lying for a long time in one position.
Erb-Duchenne paralysis paralysis of the upper roots of the
brachial plexus due to destruction of the fifth and sixth cervical roots, without involvement of the small muscles of the hand. Called also
Erb's palsy.
facial paralysis weakening or paralysis of the facial nerve, as in
bell's palsy.
familial periodic paralysis a hereditary disease with recurring attacks of rapidly progressive flaccid paralysis, associated with a fall in (hypokalemic type), a rise in (hyperkalemic type), or normal (normokalemic type) serum potassium levels; all three types are inherited as autosomal dominant traits.
flaccid paralysis paralysis with loss of muscle tone of the paralyzed part and absence of
tendon reflexes.
infantile cerebral ataxic paralysis a congenital condition due to defective development of the frontal regions of the brain, affecting all extremities.
ischemic paralysis local paralysis due to stoppage of circulation.
Klumpke's paralysis (Klumpke-Dejerine paralysis) atrophic paralysis of the lower arm and hand, due to lesion of the eighth cervical and first dorsal thoracic nerves.
motor paralysis paralysis of the voluntary muscles.
periodic paralysis 1. any of various diseases characterized by episodic flaccid paralysis or muscular weakness.
Saturday night paralysis paralysis of the extensor muscles of the wrist and fingers, so called because of its frequent occurrence in alcoholics. It is most often due to prolonged compression of the radial (musculospiral) nerve, and, depending upon the site of nerve injury, is sometimes accompanied by weakness and extension of the elbow. Called also
musculospiral or
radial paralysis.
sensory paralysis loss of sensation resulting from a morbid process.
sleep paralysis paralysis occurring at awakening or sleep onset; it represents extension of the atonia of REM
sleep into the waking state and is often seen in those suffering from
narcolepsy or
sleep apnea. Called also
waking paralysis.
spastic paralysis paralysis with rigidity of the muscles and heightened deep muscle reflexes and
tendon reflexes.
tick paralysis progressive ascending flaccid motor paralysis following the bite of certain ticks, usually
Dermacentor andersoni; first seen in children and domestic animals in the northern Pacific region of North America, and now seen in other parts of the world.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.