CHAPTER 45

CHRONIC DISORDERS OF NEUROLOGIC FUNCTION

SEIZURE DISORDER• Transient neurologic event of paroxysmal

abnormal or excessive cortical electrical discharges that are manifested by disturbances of skeletal motor function, sensation, autonomic visceral function, behavior, or consciousness• Due to an alteration in membrane potential

that makes certain neurons abnormally hyperactive and hypersensitive to changes in their environment

BRAIN AND CEREBELLAR DISORDERS

BRAIN AND CEREBELLAR DISORDERS (CONT.)

• Generalized seizures involve the entire brain from the onset of the seizure• Partial seizures are those in which abnormal

electrical activity is restricted to one brain hemisphere• Status epilepticus is a continuing series of

seizures without a period of recovery between seizure episodes and can be life-threatening

BRAIN AND CEREBELLAR DISORDERS (CONT.)

Diagnosis and Treatment of Seizures• Electroencephalograms assess the

electrical patterns of brain regions• Laboratory studies identify

metabolic/nutritional deficits, infections, and exposure to toxins• Antiseizure medications prevent or reduce

seizure episodes; seizure precautions prevent injury

DEMENTIA• A syndrome associated with many

pathologic processes and characterized by progressive deterioration and continuing decline of memory and other cognitive changes• Important to first rule out manageable

causes of dementia; often cause unknown

DEMENTIA (CONT.)• The dementia of Alzheimer disease is

characterized by degeneration of neurons in temporal and frontal lobes, brain atrophy, amyloid plaques, and neurofibrillary tangles• Cause remains unknown, although genetic

and environmental triggers are suggested• Synthesis of brain acetylcholine is deficient

and treatment is aimed at increasing acetylcholine levels by reducing acetylcholine reuptake

DEMENTIA (CONT.)

PARKINSON DISEASE• May be idiopathic or a consequence of the

use of certain drugs• Dopamine deficiency in the basal ganglia is

associated with symptoms of motor impairment• Difficulty initiating and controlling

movements results in akinesia, tremor, and rigidity• Tremor occurs at rest and hand tremors

exhibit pill-rolling movements• Attempts to passively move the extremities

are met with cogwheel rigidity

PARKINSON DISEASE (CONT.)

PARKINSON DISEASE (CONT.)• General lack of movement, loss of facial

expression, drooling, propulsive gait, and absent arm swing• Treatment is aimed at restoring brain

dopamine levels or activity by administration of dopamine precursors, dopamine agonists, monoamine oxidase inhibitors, and anticholinergics• Antidepressant therapy may be needed and

surgical procedures may be helpful for motor symptoms

PARKINSON DISEASE (CONT.)

CEREBRAL PALSY• Diverse group of crippling syndromes that

appear during childhood and involve permanent, nonprogressive damage to motor control areas of the brain• Classified on the basis of neurologic signs

and symptoms, with the major types involving spasticity, ataxia, dyskinesia, or a mix of one or more of the three

CEREBRAL PALSY (CONT.)• Etiology may include prenatal infections, or

diseases of the mother; mechanical trauma to the head before, during, or after birth; exposure to nerve-damaging poisons or reduced oxygen supply to the brain• Treatment varies according to the nature

and extent of brain damage• Muscle relaxants, anticonvulsant drugs,

orthopedic surgery, casts, braces, and traction are among the therapies used

HYDROCEPHALUS• Characterized by abnormal accumulation of

fluid in the cerebroventricular system• Normal pressure hydrocephalus is due to an

increased volume of CSF• Obstructive hydrocephalus is due to an

obstruction to the flow of CSF• Communicating hydrocephalus occurs due

to abnormal absorption of CSF

HYDROCEPHALUS (CONT.)

HYDROCEPHALUS (CONT.)• Medical treatment is limited• Obstructions may be corrected surgically• The most effective treatment for

management of hydrocephalus is surgical correction employing a shunt

HYDROCEPHALUS (CONT.)

CEREBELLAR DISORDERS• Cerebellum is responsible for coordinated

control of muscle action, excitation and inhibition of postural reflexes, and maintenance of balance• Etiology of cerebellar disorders includes

abscess, hemorrhage, tumors, trauma, viral infection, or chronic alcoholism• Clinical manifestations include ataxia,

hypotonia, intention tremors, and disturbances in gait and balance

MULTIPLE SCLEROSIS• MS is a demyelinating disease of the CNS

that primarily affects young adults• Risk of contracting MS is greater for persons

living above the 37th parallel• Cause unknown, but immunologic

abnormalities and environmental factors are suspected• Demyelination can occur throughout the

CNS but often affects the optic and oculomotor nerves and spinal nerve tracts

SPINAL CORD AND PERIPHERAL NERVE

DISORDERS

MULTIPLE SCLEROSIS• Symptoms are slowly progressive; the

disease is marked by exacerbations and remissions• Symptoms may include double vision,

weakness, poor coordination, and sensory deficits; bowel and bladder control may be lost; memory impairment is common• Management is symptomatic; short-term

steroid therapy may be helpful during acute exacerbations, and immune-modifying drugs may slow progression of symptoms

MULTIPLE SCLEROSIS (CONT.)

SPINA BIFIDA• Developmental anomaly characterized by

defective closure of the bony encasement of the spinal cord (neural tube) through which the spinal cord and meninges may or may not protrude

• If anomaly not visible, condition is called spina bifida occulta

• If there is an external protrusion of the saclike structure, the condition is called spina bifida cystica, and further classified according to the extent of neural involvement

• Treatment is based on the severity of the defect and neurologic dysfunction

AMYOTROPHIC LATERAL SCLEROSIS

• ALS is a progressive disease affecting both the upper and lower motor neurons• Cause remains unknown• Weakness and wasting of the upper

extremities usually occur, followed by impaired speech, swallowing, and respiration• Typically occurs between the ages of 40-60

years and affects men more than women

AMYOTROPHIC LATERAL SCLEROSIS (CONT.)

• Clinical manifestations include weakness, atrophy, cramps, stiffness, and irregular twitching of muscle fibers• Diagnosis is based on clinical signs and

symptoms, EMG, nerve conduction studies, MRI, and serum laboratory testing• The glutamate inhibitor, riluzole, may be

helpful in managing ALS

SPINAL CORD INJURY• SCI is usually traumatic, a result of motor

vehicle accidents, falls, penetrating wounds, or sports injuries• The cord may be compressed, transected,

or contused• Further injury may result from hemorrhage,

swelling, and ischemia

SPINAL CORD INJURY (CONT.)

SPINAL CORD INJURY (CONT.)• Spinal shock occurs immediately following

SCI and is characterized by temporary loss of reflexes below the level of injury• Muscles are flaccid; skeletal and autonomic

reflexes are lost• Neurogenic shock may occur after SCI due

to peripheral vasodilation• Hypotension and circulatory collapse can occur;

high spinal cord injuries can affect respiratory muscles, leading to ventilatory failure

SPINAL CORD INJURY (CONT.)

SPINAL CORD INJURY (CONT.)• Autonomic dysreflexia is an acute reflexive

response to sympathetic activation below the level of injury• Visceral stimulation (full bladder or bowel) and

activation of pain receptors below the injury are common stimuli

• Manifestations include hypertension, bradycardia, flushing above the level of injury, and clammy skin below the level of injury

• Prompt removal of the offending stimulus; aggressive blood pressure management may be needed

SPINAL CORD INJURY (CONT.)• Treatment includes appropriate stabilization

of spinal vertebrae• May be accomplished surgically with internal

fixation or with external fixation and bracing • High-dose methylprednisolone may be used

to decrease secondary injury• Intensive rehabilitation is required to

maximize function

GUILLAIN-BARRÉ SYNDROME• Characterized by muscle weakness that

begins in the lower extremities and spreads to the proximal spinal neurons• Cause unknown; postinfectious

immunologic mechanism is suspected• Progressive ascending weakness or

paralysis, may affect respiratory muscles• Treatment is supportive; spontaneous

recovery usually occurs

BELL PALSY• Bell palsy, or neuropathy of the facial

nerve; paralysis of the muscles on one side of the face• Symptoms include unilateral facial

weakness, facial droop and diminished eye blink, hyperacusis, and decreased lacrimation• Often self-limiting condition with unknown

cause• Treatment is supportive, and spontaneous

recovery usually occurs

BELL PALSY (CONT.)