NCLEX: Neurologic disorders

 Neurologic disorders: Myasthenia gravis

Focus topic: Neurologic disorders

Myasthenia gravis produces sporadic but progressive weakness and abnormal fatigue in striated (skeletal) muscles. This weakness and fatigue are exacerbated by exercise and repeated movement but improved by anticholinesterase drugs. Usually, myasthenia gravis affects muscles innervated by the cranial nerves (face, lips, tongue, neck, and throat), but it can affect any muscle group.

Neurologic disorders: Hard to predict

Focus topic: Neurologic disorders

Myasthenia gravis has an unpredictable course that includes periods of exacerbation and remission. There’s no known cure. Drug treatment has improved the prognosis and allows patients to lead relatively normal lives, except during exacerbations. However, if the disease involves the respiratory system, it can be life-threatening. Myasthenia gravis affects 2 to 20 people per 100,000. It’s most common in women between ages 18 and 25 and in men between ages 50 and 60.

What causes it

The cause of myasthenia gravis isn’t known; however, it commonly accompanies autoimmune and thyroid disorders. In fact, 15% of all patients with myasthenia gravis have thymomas.

Pathophysiology

The patient’s blood cells and thymus gland produce antibodies that block, destroy, or weaken the neuroreceptors that transmit nerve impulses, causing a failure in transmission of nerve impulses at the neuromuscular junction.

What to look for

Common signs of myasthenia gravis include:

  • gradual, progressive skeletal muscle weakness and fatigue that worsens during the day
  • weak eye closure, ptosis, and diplopia
  • blank, masklike facial expression
  • difficulty chewing and swallowing
  • a hanging jaw
  • bobbing motion of the head
  • symptoms of respiratory failure if respiratory muscles are involved.

Neurologic disorders

What tests tell you

  • The Tensilon test confirms the diagnosis by temporarily improving muscle function after an I.V. injection of edrophonium or neostigmine. Long-standing ocular muscle dysfunction, however, may not respond. This test also differentiates a myasthenic crisis from a cholinergic crisis.
  • Electromyography helps differentiate nerve disorders from muscle disorders.
  • Nerve conduction studies test for receptor antibodies.

How it’s treated

Treatment is symptomatic. Anticholinesterase drugs, such as pyridostigmine (Mestinon), counteract fatigue and muscle weakness and enable about 80% of normal muscle function. However, these measures become less effective as the disease worsens. Corticosteroids may help to relieve symptoms. A patient may undergo plasmapheresis. One with thymomas requires thymectomy, which may lead to remission in adult-onset myasthenia gravis.

Neurologic disorders: In a crisis

Focus topic: Neurologic disorders

Acute exacerbations that cause severe respiratory distress necessitate emergency treatment. Tracheotomy, positive-pressure ventilation, and vigorous suctioning to remove secretions usually yield improvement in a matter of days. Anticholinesterase drugs aren’t effective during myasthenic crisis, so they’re discontinued until respiratory function begins to improve. A crisis requires immediate hospitalization and vigorous respiratory support.

What to do

  • Establish an accurate neurologic and respiratory baseline. Help remove secretions as they accumulate. Be alert for signs of an impending crisis (increased muscle weakness, respiratory distress, and difficulty talking or chewing).
  • For the best results, administer drugs at evenly spaced intervals and on time, as ordered. Be prepared to give atropine for anticholinesterase overdose or toxicity.
  • Plan periods of exercise, meals, patient care, and daily activities to take advantage of peaks in the patient’s energy level.
  • Provide soft, solid foods instead of liquids to reduce the risk of choking. Always sit the patient up to eat.
  • Encourage the patient to take an active role in deciding about his care.
  • Evaluate the patient. Look for normal vital signs, evidence of adequate hydration and normal elimination, skin that’s free from sores or problems, and an optimal capacity for activity.
  • Encourage the patient and his family to discuss their feelings, especially feelings of frustration, grief, or loss. Listen and provide emotional support.

Neurologic disorders: Parkinson’s disease

Focus topic: Neurologic disorders

Parkinson’s disease, a slowly progressive and degenerative disorder, is one of the most common neurologic disorders in the United States. Parkinson’s disease may appear at any age; however, it’s rare in people younger than age 30 and risk increases with age. Parkinson’s disease most commonly affects men, and strikes 1 out of every 100 people older than age 60.

What causes it

In most instances, the cause of Parkinson’s disease isn’t known. However, some cases result from exposure to toxins, such as manganese dust and carbon monoxide, that destroy cells in the substantia nigra of the brain.

Pathophysiology

Parkinson’s disease affects the extrapyramidal system, which influences the initiation, modulation, and completion of movement. The extrapyramidal system includes the corpus striatum, globus pallidus, and substantia nigra.
In Parkinson’s disease, a dopamine deficiency occurs in the basal ganglia, the dopamine-releasing pathway that connects the substantia nigra to the corpus striatum. Reduction of dopamine in the corpus striatum upsets the normal balance between the dopamine (inhibitory) and acetylcholine (excitatory) neurotransmitters. Symptoms occur when affected brain cells can no longer perform their normal inhibitory function within the CNS.

What to look for

  • Insidious tremor that begins in the fingers (unilateral pill-roll tremor), increases during stress or anxiety, and decreases with purposeful movement and sleep
  • Muscle rigidity that resists passive muscle stretching; it may be uniform (lead-pipe rigidity) or jerky (cogwheel rigidity)
  • Difficulty walking (gait lacks normal parallel motion and may be retropulsive or propulsive)
  • Bradykinesia or slowing of muscle movements
  • High-pitched monotone voice
  • Drooling and dysphagia
  • Masklike facial expression, poor blink reflex, and wide-open eyes
  • Loss of postural control (body bent forward while walking)
  • Slowed, monotonous, slurred speech that may become severely dysarthric
  • Oculogyric crises (eyes are fixed upward, with involuntary tonic movements) and, occasionally, blepharospasm

What tests tell you
Laboratory test results rarely identify Parkinson’s disease. Consequently, diagnosis depends on the patient’s age, health history, and presence of characteristic signs of disease. However, urinalysis may reveal decreased dopamine levels, and CT scan or MRI may help rule out other disorders such as an intracranial tumor.

How it’s treated
There’s no known cure for Parkinson’s disease. Treatment focuses on relieving symptoms and maintaining as high a level of function as possible for as long as possible. Drug therapy and physical therapy are the modes of treatment. In severe disease, stereotactic neurosurgery may be used.

Neurologic disorders: Levodopa — with or without the carbs

Focus topic: Neurologic disorders

Typical drug therapy includes levodopa (Dopar), a dopamine replacement that’s most effective in the early stages. Levodopa can cause significant adverse reactions, so it’s frequently given in combination with carbidopa, which halts peripheral dopamine synthesis. If carbidopa/levodopa (Sinemet) proves ineffective or too toxic, alternative drug therapy may include:

  • dopamine agonists, such as bromocriptine (Parlodel), pramipexole (Mirapex), or ropinirole (Requip)
  • anticholinergics such as trihexyphenidyl
  • antihistamines such as diphenhydramine (Benadryl)
  • amantadine (Symmetrel), an antiviral agent
  • selegiline, an enzyme inhibitor.

Neurologic disorders: A class by itself

Focus topic: Neurologic disorders

A new class of drugs, catechol-O-methyltransferase (COMT) inhibitors (tolcapone [Tasmar]), which are combined with levodopa, are achieving some measure of success in prolonging relief from symptoms. These drugs block the enzyme that breaks down levodopa before it enters the brain. This enhances and prolongs the effect of levodopa. In younger patients, dopamine agonists may be used before COMT inhibitors. Unfortunately, prolonged use of any drug tends to reduce its effectiveness.

Neurologic disorders: In stereo

Focus topic: Neurologic disorders

If drug therapy fails, stereotactic neurosurgery may offer a viable alternative. This procedure interrupts the function of the subthalamic nucleus, the pallidum, or the ventrolateral nucleus of the thalamus to prevent involuntary movement. This treatment is most effective in younger and otherwise healthy patients who have unilateral tremor or muscle rigidity. Neurosurgery is a palliative measure that can only relieve symptoms, not reverse the disease.

Neurologic disorders: One deep brain

Focus topic: Neurologic disorders

In some cases, deep brain stimulation is used to stop uncontrolled movements. The surgeon places electrodes in the thalamus or globus pallidus. Leads connect the electrodes to a device that the patient can activate when symptoms occur.

Neurologic disorders: Get physical

Focus topic: Neurologic disorders

Physical therapy complements drug treatment and neurosurgery to maintain normal muscle tone and function. Typically, physical therapy includes active and passive ROM exercises, routine daily activities, walking, and baths and massage to help relax muscles.

What to do

  • If the patient has had surgery, monitor his LOC and vital signs closely for hemorrhage or increased ICP.
  • Encourage independence. A patient with excessive tremor may have better control if he sits in a chair and uses the chair’s arms to steady himself. Remember that fatigue can exacerbate symptoms and, in turn, increase the patient’s dependence on others.
  • Establish a regular bowel routine by encouraging the patient to drink 2 qt (2 L) of liquid daily and eat high-fiber foods. An elevated toilet seat can make it easier to transition from standing to sitting.
  • Encourage the patient to remain as active as possible. The disease progresses more slowly in those who stay active.
  • Encourage the patient and his family to ask questions. Listen to their concerns and provide succinct, accurate answers.
  • Evaluate the patient. Optimal oxygen saturation levels will indicate adequate respiratory function. He should have normal urinary function and be free from UTI. In addition, he should perform normal daily activities within the limits imposed by his condition. The patient and his family should understand Par kin son’s disease and its treatment.

Neurologic disorders: Seizure disorder

Focus topic: Neurologic disorders

Patients with seizure disorders rarely have just one seizure. They’re susceptible to recurrent seizures — paroxysmal events associated with abnormal electrical discharge of neurons in the brain. These discharges may be focal or diffuse, and the sites of the discharges determine the clinical manifestations that occur during the attack.
Seizures are among the most commonly observed neurologic dysfunctions in children and can occur with widely varying CNS conditions. The onset of seizures in adults should lead health care providers to suspect brain tumor or head injury.

Neurologic disorders

What causes it
Seizures are idiopathic (cause unknown) in about one-half of all cases. For the other half, possible causes include:

  • genetic disorders or degenerative disease, such as phenylketonuria or tuberous sclerosis
  • birth trauma (inadequate oxygen supply to the brain, blood incompatibility, or hemorrhage)
  • infectious diseases (meningitis, encephalitis, or brain abscess)
  • ingestion of toxins (mercury, lead, or carbon monoxide)
  • brain tumors, head injury or trauma
  • stroke (hemorrhage, thrombosis, or embolism).

Pathophysiology

Although the cause of seizures remains unclear, it’s thought that a group of neurons may lose afferent stimulation (ability to transmit impulses from the periphery toward the CNS) and function as a seizure focus. These neurons are hypersensitive and easily activated. In response to changes in the cellular environment, the neurons become hyperactive and fire abnormally.

Neurologic disorders: Fighting fire with fire

Focus topic: Neurologic disorders

Upon stimulation, the seizure focus fires and spreads electrical current toward the synapse and surrounding cells. These cells fire in turn, and the impulse cascades to one side of the brain (a partial seizure), both sides of the brain (a generalized seizure), or toward the cortical, subcortical, or brain stem areas. A continuous seizure state known as status epilepticus can cause respiratory distress and even death.

What to look for

There are generally six types of seizures:

  • simple partial
  • complex partial
  • absence
  • myoclonic
  • generalized tonic-clonic
  • atonic.

Neurologic disorders: Simple partial seizure

Focus topic: Neurologic disorders

  • Sensory symptoms (flashing lights, smells, auditory hallucinations)
  • Autonomic symptoms (sweating, flushing, pupil dilation)
  • Psychic symptoms (dream states, anger, fear)

Neurologic disorders: Complex partial seizure

Focus topic: Neurologic disorders

  • Altered LOC
  • Amnesia

Neurologic disorders: Absence seizure

Focus topic: Neurologic disorders

  • A brief change in LOC indicated by blinking or rolling of the eyes, a blank stare, and slight mouth movements

Neurologic disorders: Myoclonic seizure

Focus topic: Neurologic disorders

  • Brief involuntary muscular jerks of the body or extremities

Neurologic disorders: Generalized tonic-clonic seizure

Focus topic: Neurologic disorders

  • Typically beginning with a loud cry
  • Change in LOC
  • Body stiffening, alternating between muscle spasm and relaxation
  • Tongue biting, incontinence, labored breathing, apnea, cyanosis
  • Upon wakening, possible confusion and difficulty talking
  • Drowsiness, fatigue, headache, muscle soreness, weakness

Neurologic disorders

Neurologic disorders: Atonic seizure

Focus topic: Neurologic disorders

  • General loss of postural tone
  • Temporary loss of consciousness

What tests tell you

Primary diagnostic tests include:

  • CT scan and MRI, which provide density readings of the brain and may indicate structural abnormalities
  • EEG, which may show paroxysmal abnormalities that confirm the diagnosis of seizure disorder by providing evidence of the continuing tendency to have seizures. (A negative EEG doesn’t rule out seizure disorder because the paroxysmal abnormalities occur intermittently.)

Other informative tests include:

  • serum glucose, electrolyte, drug, and calcium levels
  • lumbar puncture
  • brain scan
  • PET scan
  • cerebral angiography.

How it’s treated

Typically, treatment consists of drug therapy. The most commonly prescribed drugs are phenytoin (Dilantin), carbamazepine (Tegretol), phenobarbital, and primidone (Mysoline) for generalized tonic-clonic seizures and complex partial seizures. Valproic acid (Depakene), clonazepam (Klonopin), and ethosuximide (Zarontin) are commonly prescribed for absence seizures.
If drug therapy fails, the surgeon may choose to surgically remove a demonstrated focal lesion in an attempt to bring an end to seizures. Emergency treatment for status epilepticus usually consists of diazepam, lorazepam, fosphenytoin (Cerebyx), or phenobarbital; 50% dextrose I.V. (when seizures are secondary to hypoglyce mia); and thiamine I.V. (in chronic alcoholism or withdrawal). Rectal preparations of diazepam and oral solutions of diazepam and lorazepam are concentrated and fast-acting.

What to do

  • Monitor the patient for signs and symptoms of medication toxicity, such as nystagmus, ataxia, lethargy, dizziness, drowsiness, slurred speech, irritability, nausea, and vomiting.
  • Administer phenytoin according to guidelines (not more than 50 mg/minute), and monitor the patient’s vital signs and cardiac status often.

Neurologic disorders

  • Evaluate the patient to determine the effectiveness of the medication; seizure activity should decrease or stop. Note whether the patient has expressed his feelings regarding his illness to his friends or family.

Neurologic disorders: Stroke

Focus topic: Neurologic disorders

Stroke is the sudden interruption of circulation in one or more of the blood vessels supplying the brain. During a stroke, brain tissue fails to receive adequate oxygenation, resulting in serious tissue damage or necrosis. The speed with which circulation is restored determines the patient’s chances for complete recovery.

Neurologic disorders: Not the back stroke

Focus topic: Neurologic disorders

Strokes are classified by their course of progression. The least severe type, called transient ischemic attack, results from a temporary interruption of blood flow. A progressive stroke, or stroke-in-evolution (thrombus-in-evolution), begins with a slight neurologic deficit that worsens over a day of two. In a complete stroke, the patient experiences maximum neurologic impairment immediately.

Neurologic disorders: Factor this in

Focus topic: Neurologic disorders

Stroke is the third most common cause of death in the United States and the most common cause of neurologic disability. Risk factors include a history of TIAs, atherosclerosis, hypertension, arrhythmias, lack of exercise, use of hormonal contraceptives, smoking, and a family history of cerebrovascular disease.

What causes it

  • Thrombosis of the cerebral arteries that supply the brain or the intracranial vessels, occluding blood flow
  • Embolism from a thrombus that formed outside the brain — forexample, in the heart, aorta, or common carotid artery
  • Hemorrhage from an intracranial artery or vein, possibly due to hypertension, ruptured aneurysm, AVM, trauma, hemorrhagic disorder, or septic embolism

Neurologic disorders

Pathophysiology

Thrombosis, embolus, and hemorrhage act in different ways.

  • Thrombosis causes blockage and edema in the affected vessel and ischemia in the tissues supplied by the vessel.
  • Embolus cuts off circulation in the cerebral vasculature by lodging in a narrow portion of the artery, causing ischemia and edema. If the embolus is septic and the infection extends beyond the vessel wall, an aneurysm may form, which increases the risk of a sudden rupture and cerebral hemorrhage.
  • In hemorrhage, an artery in the brain leaks, rapidly reducing the blood supply to tissues served by the artery. Blood accumulates deep within the brain, causing even greater damage by further compromising neural tissue.

What to look for

When assessing signs of stroke, “sudden” is the key word. Signs typically include the sudden onset of:

  • headache with no known cause
  • numbness or weakness of the face, arm, or leg, especially on one side of the body
  • confusion, trouble speaking or understanding
  • trouble seeing or walking, dizziness, loss of coordination.

What tests tell you

  • MRI or a CT scan shows evidence of thrombotic or hemorrhagic stroke, tumor, or hydrocephalus.
  • Brain scan reveals ischemia, but may not be positive for up to 2 weeks after the stroke.
  • In hemorrhagic stroke, lumbar puncture may reveal blood in the CSF.
  • Carotid ultrasound may detect a blockage, stenosis, or reduced blood flow.
  • Ophthalmoscopy may detect signs of hypertension and atherosclerosis in retinal arteries.
  • Angiography can help pinpoint the site of occlusion or rupture.
  • EEG may help localize the area of damage.
  • Other laboratory studies, such as urinalysis, coagulation studies, CBC, serum osmolality, and electrolyte, glucose, lipid profile, antinuclear antibody, creatinine, and blood urea nitrogen levels, help establish baseline organ function.

How it’s treated
Medical management of stroke commonly includes physical rehabilitation, diet and drug regimens to help reduce risk factors, possibly surgery, and care measures to help the patient adapt to specific deficits, such as motor impairment and paralysis.

Neurologic disorders: Surgery possibilities

Focus topic: Neurologic disorders

Depending on the stroke’s cause and extent, the patient may undergo craniotomy to remove a hematoma, endarterectomy to remove atherosclerotic plaques from an arterial wall, placement of stents to reduce blockages, or extracranial bypass to circumvent a blocked artery. Ventricular shunts may be needed to drain CSF.

Neurologic disorders: Take two

Focus topic: Neurologic disorders

Drug therapy for stroke includes:

  • low-dose aspirin (Ecotrin) or clopidogrel (Plavix) as an antiplatelet agent to prevent recurrent stroke (but not in hemorrhagic stroke)
  • benzodiazepines, such as lorazepam and diazepam, to treat seizures
  • anticonvulsants to treat or prevent seizures after the patient’s condition has stabilized
  • thrombolytics, such as alteplase (Activase) for emergency treatment of embolic stroke (typically within 3 hours of onset), or aspirin or hep arin for patients with embolic or thrombotic stroke who aren’t candidates for alteplase
  • stool softeners, such as bisacodyl, to prevent straining, which increases ICP
  • antihypertensives and antiarrhythmics to reduce risks associated with recurrent stroke
  • corticosteroids, such as dexamethasone, to minimize cerebral edema
  • analgesics to relieve headache following a hemorrhagic stroke.

What to do

  • Maintain a patent airway and oxygenation. Loosen constricting clothes. Watch the patient’s cheeks. If one side “balloons” with respiration, that’s the side the stroke affected. If unconscious, the patient may aspirate saliva; keep him in a lateral position to promote drainage, or suction as needed. Insert an artificial airway and start mechanical ventilation or supplemental oxygen if needed.
  • Check the patient’s vital signs and neurologic status. Record observations and report any significant changes, such as changes in pupil dilation, signs of increased ICP, and nuchal rigidity or flaccidity. Monitor blood pressure, LOC, motor function (voluntary and involuntary movements), senses, speech, skin color, and temperature. A subsequent stroke may be imminent if blood pressure rises suddenly, the pulse is rapid and bounding, and the patient complains of a sudden headache.

Neurologic disorders: Checking for color changes

Focus topic: Neurologic disorders

  • Watch for signs and symptoms of pulmonary emboli, such as chest pain, shortness of breath, dusky color, tachycardia, fever, and changed sensorium. If the patient is unresponsive, monitor his arterial blood gas levels often, and alert the practitioner to increased P aCO2 or decreased partial pressure of arterial oxygen.
  • Maintain fluid and electrolyte balance. If the patient can drink fluids, offer them as often as fluid limitations permit. Give I.V. fluids as ordered; yet, never give a large volume rapidly as this can increase ICP. Offer the bedpan or help the patient to the bathroom every 2 hours. If incontinent, the patient may need an indwelling urinary catheter; however, this increases the risk of infection.
  • Ensure adequate nutrition. Check for gag reflex before offering small amounts of semisolid foods. Place the food tray within the patient’s visual field. If the patient can’t eat, insert an NG tube.
  • Manage GI problems. Be alert for signs of straining as this increases ICP. Modify the patient’s diet and administer a stool softener, as ordered. If the patient is nauseous, position him on his side to prevent aspiration of vomit. Provide antacids to reduce the risk of ulcer formation.
  • Clean and irrigate the patient’s mouth or dentures to remove food particles.
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Neurologic disorders: Keeping a watchful eye

Focus topic: Neurologic disorders

  • Provide meticulous eye care. Remove secretions with a gauze pad and sterile normal saline solution. Instill eye drops, as ordered. If he’s unable to close his eye, cover it with a patch.
  • Position the patient. High-top sneakers, splints, or a foot board will help prevent foot drop and contracture. To prevent pressure ulcers, re-position the patient often or use a special mattress. Turn the patient at least once every 2 hours to prevent pneumonia. Raise the hand on the affected side to control dependent edema.
  • Help the patient exercise. Perform ROM exercises for the affected and unaffected sides. Show him how to use his unaffected limbs to exercise his affected limbs.
  • Administer medications, as ordered, and monitor the patient for adverse reactions.

Neurologic disorders: Speak no evil

Focus topic: Neurologic disorders

  • Maintain communication with the patient. If he’s aphasic, set up a simple method of communicating. Remember that an unresponsive patient may be able to hear. Don’t say anything in his presence that you wouldn’t want him to hear.
  • Provide emotional support and establish a rapport. Spend time with the patient. Set realistic short-term goals and get the patient’s family involved in his care when possible.
  • Evaluate the patient. Look for a patent airway, normal breath sounds, adequate mobility, stable or improving LOC, and proper nutrition. Encourage the patient and his family as they cope with the disorder.

Neurologic disorders

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