Palsy

• ANATOMY OR SYSTEM AFFECTED: Muscles, musculoskeletal system, nerves, nervous system
• CAUSES: May include genetic and environmental factors, congenital anomalies, trauma during childbirth, reduced blood flow to affected nerves, viral infection, injury in front of ear (trauma, surgery)
• SYMPTOMS: May include paralysis (partial or complete); muscle weakness, wasting, or rigidity; awkward gait; impaired facial movement; impaired speech; mental impairment; seizure disorders
• DURATION: Acute to chronic
• TREATMENTS: Drug therapy (oral corticosteroids like prednisone, antiviral drugs such as acyclovir); surgery; application of warmth

DEFINITION: A paralysis or partial paralysis that is usually accompanied or followed by muscle weakness and muscle wasting over the affected area; small amounts of residual electrical activity present in some cases with uncontrolled activity

Causes and Symptoms

In general, the term “palsy” describes any type of dysfunction of the motor nerves that impairs or reduces the conscious control of muscles. The paralysis or loss of motor control is usually accompanied or followed by weakness and wasting of the muscles in the affected area.

The most common type of palsy is Bell’s palsy, a paralysis of the seventh cranial nerve, or facial nerve, often accompanied by pain over part or all of the affected area. The number of muscles involved varies. The paralysis usually occurs on one side of the face at a time, resulting in the undamaged muscles of the opposite side pulling the facial skin toward that side. Typically, the eye on the affected side remains open constantly because the muscles that close it have been affected; attempts by the patient to close the eye result in the eyeball rotating upward. The rest of the face on the affected side generally droops but remains flat; the brow fails to wrinkle, and the cheeks never thicken. Smiles and other facial expressions are asymmetrically contorted.

Thorough neurological testing is needed to assess how much damage has been done and which branches of the facial nerve have been affected. If the damage affects either hearing or taste, this finding indicates that the damage is closer to the root of the facial nerve, and the patient’s chances for recovery are correspondingly much lower. If only a few muscles are involved, it indicates that the damage is farther from the root of the nerve, which usually forecasts a better chance of recovery. In most cases, Bell’s palsy is thought to arise from a reduced blood supply to the affected nerves. Viral infections by herpes simplex or herpes zoster (shingles) are also frequent causes; these viral infections are believed to cause demyelination (deterioration of the myelin sheath that insulates nerves) of the affected parts of the facial nerve. Other causes include injuries to the area just below or in front of the external ear resulting from blows to the head, surgery in this region, or other types of trauma.

Another common type of palsy is cerebral palsy, an impairment of movement and posture caused in most cases by injury, malformation, or other damage to the immature brain. Cerebral palsy is a group of paralytic disorders that begin during intrauterine development, at birth, or in early infancy. The extent of the paralysis varies, often involving large groups of muscles while sparing others. Those muscles that are not totally paralyzed are often uncoordinated in their movements or poorly controlled; this is especially true of large muscle movements such as those of the limbs. Many patients exhibit a “scissors gait” in which the lower limbs are crossed, and the one behind must be swung sideways before it is placed in front of the other limb. In addition to the lack of muscular control of the limbs, other symptoms include spasms, athetoid (slow, rhythmic, and wormlike) movements, or muscular rigidity. Speech can be difficult or unclear when the muscles used for speaking are affected.

Mental deterioration may occur in some cases but not in others: Some patients with cerebral palsy develop intellectual disability, while others display brilliant artistic or literary talents. Some patients with cerebral palsy also experience seizure disorders such as epilepsy. Almost all cases of cerebral palsy are accompanied by some other type of neurological impairment, the nature of which varies greatly. In general, cerebral palsy is a nonprogressive type of disease; that is, it does not continually worsen. Afflicted individuals generally experience a normal lifespan, though with impaired motor functions.

The most common types of cerebral palsy are those that occur in infancy or earlier. Of this group, causes include cerebral hemorrhage (intrauterine stroke), infections that impact fetal brain development (cytomegalovirus, rubella, or toxoplasmosis), chromosomal anomalies, injuries received at birth, premature birth, oxygen deprivation during birth, embryonic malformations, untreated severe jaundice, premature detachment of the placenta during the birth process, and incompatibility between the Rh blood types of mother and child. Many causes, such as cerebral hemorrhage or injuries, may occur either during intrauterine life or at birth. Brain injuries caused by low oxygen levels (anoxia or hypoxia) can arise before, during, or after birth and can result from damage to the blood vessels, birth trauma, or infectious diseases such as meningitis or encephalitis.

Cerebral palsies are classified into five types: spastic (pyramidal), ataxic, athetoid (dyskinetic or extrapyramidal), hypotonic (atonic), and mixed cerebral palsy. The pyramidal or spastic types, the most common, show muscular spasms and other symptoms that persist with age and hardly vary with changes in emotion, tension, movement, or sleep. The pyramidal tracts of the brain stem are damaged in these forms of cerebral palsy. The extrapyramidal or athetoid type involves movements originating in the basal ganglia and cerebellum, as well as the regulation of involuntary reflexes. Common symptoms include feeding issues, posture problems, floppy limbs, and stiffness in certain body regions. Ataxic cerebral palsy, accounting for less than 3 percent of all cases, involves poor coordination, depth perception, and speech, as well as shakiness or tremors and a wide gait when walking. Hypotonic cerebral palsy involves flexible joints, loose muscles, poor balance, and a lack of head control. About 15 percent of all diagnoses are mixed-type cerebral palsy, which can involve a range of symptoms characteristic of other cerebral palsy types.

Most forms of cerebral palsy can also be described as hemiplegia (involving both extremities on one side of the body only), diplegia (involving both legs more than the arms), bilateral hemiplegia (involving the arms more than the legs), or quadriplegia (involving all four extremities more or less equally).

Attempts to group various forms of cerebral palsy by their causes have historically resulted in a lack of agreement among experts. One scheme divides the causes into subependymal hemorrhage among premature infants, damage from oxygen deprivation to the growing brain, and developmental abnormalities of the nervous system.

The most common form of cerebral palsy is spastic hemiplegia, which accounts for about 70 percent of all cerebral palsies. Spastic hemiplegia results from oxygen deprivation, intrauterine and perinatal strokes, or birth complications. Some arise after birth, during the first year of life, either from head injury or from infections such as meningitis and encephalitis. A small percentage of spastic hemiplegias arise before birth from embryonic malformations or toxemia of pregnancy. The rate at which cerebral palsy occurs is higher for babies born prematurely and for large babies who may sustain injury during a difficult passage through the birth canal.

Parkinson’s disease (formerly called paralysis agitans or shaking palsy) is a neurodegenerative movement disorder involving tremors that occur when the body is at rest, often a distinctive “pill-rolling” movement of the thumb and forefinger; this tremor usually stops if a voluntary movement begins. While this condition was long considered a plasy, it is a distinct disease, though it is commonly confused with progressive Supranuclear palsy (PSP), a form of atypical Parkinsonism.

Muscle weakness, stiffness, and muscular rigidity are common, but with intermittent symptoms that come and go; movements generally become slow and difficult. The muscles involved in chewing and swallowing are often affected in Parkinson’s disease, so patients are often advised to eat high-calorie, semisoft foods that require no chewing and are more easily swallowed than liquids. Involvement of the muscles of facial expression results in a masklike expression that does not alter with changes in emotion. Patients with Parkinson’s disease often have difficulty in initiating voluntary movements; this difficulty is often described by patients as a feeling of “being frozen in place.”

The walking gait of people with Parkinson’s disease is also very characteristic: The body above the waist leans forward, the head and shoulders droop, the feet shuffle slowly (and are barely lifted from the ground), and the arms are generally held slightly flexed and motionless rather than swinging. Many patients break into a trot or run when they attempt to walk; as a result, patients often fall, most often forward. To prevent such falls, they frequently shuffle forward in very small steps. The shuffling gait is believed to result from a partial paralysis of the extrapyramidal motor system of neurons, which is generally responsible for controlling posture and coordinating motor activities.

Parkinson’s disease primarily results from a loss of brain cells that produce the neurotransmitter dopamine, particularly in the basal ganglia, deep within the cerebral hemispheres, and especially the substantia nigra, a deeper structure that sends dopamine-secreting nerve fibers to the basal ganglia. In patients with Parkinson’s disease, cells of the substantia nigra are often degenerate and pale from the loss of normal pigments, but this may be a result, rather than a cause, of the primary defect: an impairment of the brain’s ability to convert DOPA (dihydroxyphenylalanine) into the neurotransmitter dopamine.

In some animal studies, the chemical n-methyl-4-phenyl-1,2,3,4-tetrahydropyridine produced a disease very similar to Parkinson’s disease. For this reason, some researchers suspect that the disease has an environmental cause that leads to the production of a related toxic chemical that interferes with dopamine production.

Parkinson’s disease is uncommon in patients under forty, but in people over sixty, it is one of the leading neurological disorders. According to the Parkinson's Disease Foundation, about 1.1 million Americans were living with the disease in the mid-2020s, as well as about 10 million people worldwide. Most patients show mental deterioration (dementia) as the disease progresses; some experience depression, social withdrawal, and generalized apathy.

Other, less common palsies include brachial birth palsy, Erb’s palsy, Klumpke’s palsy, true or progressive bulbar palsy, pseudobulbar palsy, Féréol-Graux palsy (conjugate gaze palsy or Gubler's paralysis), posticus palsy, lead palsy, focal hand dystonia (FHD; formerly scrivener’s palsy), pressure palsy, compression palsy, and creeping or wasting palsy.

Brachial birth palsy is a paralysis of the infant’s arm resulting from an injury received at birth, involving the whole arm, the upper arm only (Erb’s palsy), or the lower arm only (Klumpke’s palsy). Erb’s palsy, a brachial birth palsy of the upper arm, is caused by an injury at birth to the brachial plexus or the posterior roots of the fifth and sixth cervical nerves; the muscles involved generally include the deltoideus, biceps brachii, and brachialis, impairing the raising of the upper arm, flexion of the elbow, or supination movements involving the forearm. In Klumpke’s palsy, which results from an injury at birth, the muscles of the forearm and the small muscles of the hand undergo atrophy; this form is often accompanied by paralysis of the cervical sympathetic nerves.

True or progressive bulbar palsy, a palsy and progressive atrophy of the muscles of the tongue, lips, palate, pharynx, and larynx, often occurs late in life and is caused by degeneration of the motor neurons leading to these muscles. Twitching or atrophy of the tongue and other affected muscles causes drooling, difficulties in swallowing, and ultimately a respiratory paralysis that results in death. Many experts consider true bulbar palsy to be a manifestation of the same disease that causes amyotrophic lateral sclerosis (ALS), which is popularly known as Lou Gehrig’s disease.

Pseudobulbar palsy (“laughing sickness”) is a paralysis of the lips and tongue that mimics true or progressive bulbar palsy, but it arises in the brain itself and is accompanied by difficulties in swallowing and by spasmodic laughter at inappropriate times. Féréol-Graux palsy, a one-sided (unilateral) paralysis of the motor nucleus of the lateral rectus muscle of one eye and the medial rectus muscle of the other eye, results from damage to the medial longitudinal fasciculus and impairs the ability to direct either eye toward the affected side. Posticus palsy is a paralysis of the posterior cricoarytenoideus muscle (cricoarytenoideus posticus), resulting in the vocal cords being held close to the midline.

Lead palsy is a paralysis of the extensor muscles of the wrist resulting from lead poisoning, while FHD (“writer’s cramp”) is a repetitive motion disorder resulting in damage to the nerve controlling the small muscles of the hand. Pressure palsy is a paralysis caused by repeated or persistent compression of a nerve or nerve trunk. Compression palsy results from nerve compression, especially of the arm, caused by pressure from the use of a crutch (crutch palsy) or from compression of a nerve during sleep. Creeping palsy and wasting palsy are general terms for progressive muscle atrophy, such as that associated with ALS.

Treatment and Therapy

Bell’s palsy is treated by various methods, including the application of warmth or the administration of oral corticosteroids (prednisone), vasodilating drugs (cortisone), or antiviral drugs (acyclovir) in severe cases. In unusual cases, surgery is performed to enlarge the passages through which the facial nerve passes to relieve compression on the nerve. Historically, physicians often recommended treating eyes that could not be closed by taping them shut, especially in sleep. This treatment is rarely used in modern medicine. Instead, physicians usually advise patients who cannot close an affected eye to wear dark glasses during the day.

Many patients with Bell’s palsy recover spontaneously without treatment. The chances that a particular individual will spontaneously recover depend on the location of the damage and the extent of muscle involvement; the cases with the most favorable outcomes are those in which the damage is more peripheral and fewer muscles are involved. Frequent, repeated testing of each small group of facial muscles is needed to assess the extent of damage and the extent of any recovery.

Diagnosis of cerebral palsy is best made by a trained neurologist through observation of the patient’s spontaneous motor movements and reflex actions. Infants who exhibit any reflex that persists beyond its appropriate age range, or any voluntary motor pattern that fails to develop at the appropriate age, should be examined more carefully for signs of nerve damage. For example, most babies can lift their heads by one month of age and their chests by two months. After three months, most babies can raise themselves up on their elbows, and by four months, onto their wrists. Newborn babies exhibit reflexes such as the Moro reflex, a flexion and “embracing” reflex in reaction to a sudden noise or other sudden stimulus or “startle”; however, the persistence of this reflex beyond six months of age (or its asymmetrical performance) may be indicative of some form of cerebral palsy. Another reflex often used in diagnosis is the “fencer” reflex, or asymmetric tonic neck reflex: Turning the baby’s head toward one side usually causes extension movements in both the arm and leg on the side toward which the chin faces, while flexion movements usually take place on the opposite side of the body. This reflex is present at birth and disappears in a few months; its persistence after six months of age should be considered suspicious.

There is no cure for cerebral palsy. Treatment generally consists of physical rehabilitation and training the patient to use whatever muscles are still capable of being consciously controlled. This is a difficult form of therapy that must be tailored to the needs of each patient because individuals experience unique combinations of motor abilities and disabilities. Some patients with cerebral palsy cannot walk on their own. Depending on the extent of muscle movement impairment, some patients may require crutches or braces, while others use motorized wheelchairs. In cases involving a speech impairment, speech therapy can help teach the patient to speak more clearly. Most types of cerebral palsy are already present during infancy; therapy for these types is rather difficult because the patient is learning the necessary motor skills (such as walking or speaking) for the first time. Palsies that arise during adolescence or adulthood respond differently to therapy because the patient is relearning previously mastered skills.

Treatment for Parkinson’s disease includes the administration of a number of drugs that are chemically related to dopamine, the missing neurotransmitter. The most common drug is levodopa (L-dopa), a derivative of a naturally occurring amino acid in the brain; it may be prescribed in combination with carbidopa to deliver levodopa to the brain. Dopamine agonists (enhancers) or antiviral drugs like amantadine have also been shown to have effects that counter the disease. In some patients with chronic facial palsy, a botulinum toxin (Botox) injection may be beneficial in relieving pain and muscle spasms.

Perspective and Prospects

The various palsies were identified in the nineteenth century. Bell’s palsy was first described by Sir Charles Bell (1774–1842), a renowned Scottish anatomist. Parkinsonism was first described by James Parkinson (1755–1824), who called it “shaking palsy”; the understanding of the neurotransmitter dopamine and the use of L-dopa in the treatment of Parkinson’s disease were developed in the late twentieth century. Cerebral palsy was first described in 1861 by a London physician, William J. Little; the famous psychoanalyst Sigmund Freud (1856–1939) published an account of this disease in 1883. The most thorough early work on this disease was published in 1889 by the distinguished Canadian physician Sir William Osler (1849–1919), who coined the term “cerebral palsies” to describe the several types of the disease.

Several types of cerebral palsy that were more common in the early twentieth century, such as those caused by the use of obstetrical forceps during delivery, decreased in incidence as a result of improved medical procedures. For larger babies that formerly faced a greater risk of cerebral hemorrhage or brain injury from passage through the mother’s pelvic girdle at birth, the increased frequency of cesarean sections has greatly reduced the rates of cerebral palsy arising at birth.

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