3. Peripheral Neuropathies



Guillain-Barré syndrome, 357.0


Myasthenia gravis, 358.00







I. Definition


A. An acute, usually rapidly progressive form of inflammatory polyneuropathy of the peripheral nerves


B. Characterized by muscular weakness, mild distal sensory loss, and autonomic dysfunction that, in about two thirds of cases, begins 5 days to 3 weeks after occurrence of an ordinary infectious disorder, surgery, or immunization


C. Guillain-Barré syndrome (GBS) is the most frequently acquired demyelinating neuropathy.


II. Etiology


A. Unknown, although an autoimmune basis is probable


B. Triggered by antecedent infection; described after upper respiratory infection, infectious mononucleosis, cytomegalovirus infection, herpes zoster, influenza A, mycoplasma, Epstein-Barr, mumps, AIDS, Lyme disease, lymphoma (especially non-Hodgkin’s), serum sickness, surgery, and heatstroke


C. In 50% to 75% of cases, GBS is associated with Campylobacter jejuni enteritis. Culture studies have shown that a high proportion of patients with GBS have C. jejuni in their stools at the time of onset of neurologic symptoms.



IV. Clinical manifestations


A. Differ somewhat between subtypes of the disease


B. Symmetric, rapidly progressive distal muscle weakness and paresthesia, beginning in the legs and ascending rapidly to the arms, face, and oropharynx. Severity of motor symptoms depends on the nerves involved.


C. Weakness is more prominent than sensory signs and symptoms and may be more prominent proximally; it can progress to total motor paralysis and death from respiratory failure.


D. Hypotonia; sphincters are spared


E. Reduced reflexes, followed by loss of deep tendon reflexes in 100% of patients


F. “Stocking” distribution sensory loss


1. Patient may have hyperesthesia, which may make the touch of a hand or a bed sheet very painful.


2. Perception of joint position, vibration, and temperature may diminish.


G. Bulbar involvement: bilateral facial and oropharyngeal paresis


H. Difficulty swallowing (because of cranial nerve involvement)


I. Urine retention


J. Respiratory paralysis (involvement of intercostal muscles)


K. Autonomic dysfunction, including blood pressure fluctuations, inappropriate antidiuretic hormone secretion, cardiac arrhythmias, and pupillary changes


V. Laboratory findings


A. CSF


1. Elevation in CSF protein (especially immunoglobulin [Ig]G) and lack of increased lymphocytes strongly suggest GBS.


2. Normal values may be seen at the beginning of the illness.


3. Elevation begins a week after symptoms occur and peaks in 4 to 6 weeks.


4. Protein elevation may be very high (greater than 1000 mg/dl).


B. CBC: Early leukocytosis may be seen with a left shift that resolves during the course of illness.


C. If diagnosis is strongly suspected, repeat lumbar puncture is indicated.



VII. Management


A. Severe acute polyneuropathy is a medical emergency.


B. Admit to the intensive care unit for constant monitoring and vigorous support of vital functions.


C. Anticipate respiratory support by mechanical ventilation.


D. Measure vital capacity (VC) and arterial blood gases. If forced expiratory volume is less than 12 to 15 ml/kg, VC is less than 1000 ml, PaO2 (partial pressure of oxygen in arterial blood) is less than 70, and/or the patient is having a difficult time clearing secretions and is aspirating, assisted ventilation may become necessary.


E. IgG


1. Therapy that has been used traditionally as an alternative to plasmapheresis (0.4 g/kg IV for 5 consecutive days)


2. Use of high-dose intravenous immune globulin G (IVIgG) may promote remyelination in demyelinating disease.


3. This treatment has replaced plasmapheresis as the therapy of choice at many institutions.


F. Plasmapheresis


1. Perform in severe cases.


2. Shortens course and reduces time on ventilator


3. Treatment of choice in those who are acutely ill; should be performed within 7 days after onset


4. Very beneficial in preventing paralytic complications


5. Patients reportedly improve more quickly, can be weaned from assisted ventilation earlier, and can ambulate earlier.


6. Contraindicated in patients with cardiovascular disease (recent myocardial infarction, unstable angina), active sepsis, and autonomic dysfunction


7. Recommendations are to use two plasma exchange treatments for mild GBS.


8. Use four or five plasma exchange treatments for severe GBS.


9. Start as soon as possible on alternating days.


G. New insights in GBS pathophysiology have emphasized the effect of cellular immune reaction and the role of proinflammatory and anti-inflammatory cytokines (especially tumor necrosis factor [TNF] and tumor growth factor [TGF]).


1. Research suggests the potential usefulness of interferon beta-1a (Ribif, 6 mIU subcutaneously on alternate days) in decreasing motor deficits.


2. Effects may be related to decreased TNF production, reduced T-cell activation and proliferation, decreased gelatinase B production, and increased TGF production.



I. Prevention of thrombophlebitis


1. Thromboembolic disease stockings (TEDS) and heparin (5000 units subcutaneously every 12 hours) or low molecular weight heparin


J. Pain management


1. Pain may be significant in GBS.


2. Suitable analgesics range from nonsteroidal anti-inflammatory agents to opioids.


K. Stress ulcer prevention, especially in those receiving ventilatory support.


L. Encourage fluid intake to maintain urine volume of 1 to 1.5 L/day.


M. Monitor serum and electrolytes to prevent water intoxication.


N. Maintain skin integrity. Protect skin from trauma and pressure. Reposition frequently.


O. Apply moist heat to relieve pain and to permit early physical therapy.

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Mar 3, 2017 | Posted by in NURSING | Comments Off on 3. Peripheral Neuropathies

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