GUILLAIN-BARRE SYNDROME(GBS)
• The Guillain-Barre syndrome is characterized by the acute onset of peripheral and cranial nerve dysfunction. Viral upper respiratory or gastrointestinal infection, immunization, or surgery often precedes neurologic symptoms by 5 days to 3 weeks. Rapidly progressive symmetric weakness, loss of tendon reflexes,
• facial diplegia, bulbar and respiratory paresis, and impaired sensation in the distal parts of the limbs are frequent. The patient's condition worsens for several days to 3 weeks, then gradually improves to normal or nearly normal function without specific therapy. •
Etiology: The cause of Guillain-Barre syndrome is unknown. A disease with a similar clinical course (i.e. similar pathologic, electrophysiologic and CSF alterations) can be induced in experimental
• animals by immunization with whole peripheral nerve, peripheral nerve myelin or, in some species, peripheral nerve myelin P2 basic protein or galactocerebroside. However, there is no definite evidence of sensitization to these antigens in human patients with spontaneous Guillain-Barre syndrome. Though GuillainBarre syndrome is frequently preceded by a viral infection, there is as yet no evidence of viral invasion of peripheral nerves or nerve roots.
Electrophysiology and Pathology:
• Nerve conduction velocities are reduced in Guillain-Barre syndrome, but studies may be normal early in the course. Distal sensory and motor latencies are prolonged. Owing to demyelination of nerve roots, Fwave conduction velocity is often slowed. Severity of neurologic abnormality correlates poorly with the degree of slowing of nerve conduction velocities. Conduction slowing may persist for months or years after clinical recovery. • Guillain-Barre syndrome is characterized
• histologically by focal segmental demyelination associated with perivascular and endoneurial infiltrates of lymphocytes and monocytes or macrophages These lesions are scattered through the peripheral nerves. nerve roots, and cranial nerves. In particularly severe lesions, there is axonal degeneration in addition to segmental demyelination. During recovery, remyelination occurs, but the lymphocytic infiltrates may persist. •
Incidence
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The Guillain-Barre syndrome is the most frequentlv acquired demyelination neuropathy, with an incidence of 0.6 to l.9cases per 100,000 people. The incidence increases gradually with age, but the disease may occur at any age. The sexes are equally affected. The incidence of Guillain-Barre syndrome is increased in patients with Hodgkin disease and may be precipitated by pregnancy, general surgery, or vaccinations. • Symptoms and signs: The Guillain-Barre syndrome often appears days to weeks after
• symptoms of a viral upper respiratory or gastrointestinal infection. The usual initial neurologic symptoms are symmetric weakness of the limbs, often accompanied by paresthesias. Unlike most other neuropathies, proximal muscles are sometimes affected more than distal muscles in the early phases of the syndrome. Occasionally, facial, extraocular, or oropharyngeal muscles may be the first to be affected; more than 50% of the patients have facial diplegia and about 50% develop
• dysphagia and dysarthria. Some patients require mechanical support of ventilation. Hyporeflexia or areflexia is present in all cases, although tendon reflexes may be normal at first. The degree of sensory impairment is variable; in some patients, all sensory modalities are preserved, but others have marked diminution in perception of joint position, vibration, pain, and temperature in a stoking-and-glove distribution. Patients occasionally develop papilledema, sensory ataxia, transient
• plantar responses, or evidence of autonomic dysfunction (e.g., orthostatic hypotension, transient hypertension. cardiac arrhythmia). Many patients have muscle tenderness and sensitivity of the nerves to pressure, but signs of meningeal irritation such as nuchal rigidity are not present. A variant form of Guillain-Barre syndrome has been described, it is characterized by gait ataxia, areflexia, and ophthalmoparesis. It is sometimes associated with pupillary abnormalities, but without weakness of the
• limbs (Miller Fisher syndrome); recovery • from this form of Guillain-Barre syndrome is almost always complete. • Laboratory Data: CSF protein content is elevated in most patients, though protein may be normal during the first few days after onset. The CSF cell count is usually normal, but patients with otherwise typical Guillain-Barre syndrome occasionally have 10 to 100 mononuclear cells per μL of CSF. The occurrence of antecedent
• Infectious mononucleosis, cytomegalovirus infection, viral hepatitis, or other viral disease may be documented by serologic studies. • Course and Prognosis: Symptoms are usually most severe within a week of onset, but may progress for 3 weeks or more. Death is an unusual result of Guillain-Barre syndrome and is generally duo to aspiration pneumonia, pulmonary embolism, intercurrent infection, or autonomic dysfunction.The rate of recovery is variable.
• In some is rapid, with restoration to normal function within a few weeks. In most, recovery is slow and not complete for many months. About 35%of patients have permanent residual deficits, generally hyporeflexia, atrophy and weakness of distal muscles, or facial paresis. A biphasic course of illness, with partial recovery followed by relapse, occurs in less than 10% of patients with the Guillain-Barre syndrome, and recurrence of the illness after full recovery occurs in about 2%.
• Diagnosis and Differential Diagnosis: • The characteristic history of subacute development of symmetric motor or sensorimotor neuropathy following a viral illness, immunization, or surgery, together with electrophysiologic findings consistent with segmental demyelination and the elevated CSF protein content with normal CSF cell count are strong presumptive evidences for the diagnosis of Guillain-Barre syndrome.
Diagnostic criteria for GuillainBarré syndrome . • Required for diagnosis • Progressive weakness of more than one limb • Distal areflexia with proximal areflexia or hyporeflexia
• Supportive of diagnosis • Progression for up to 4 weeks • Relatively symmetric deficits • Mild sensory involvement • Cranial nerve (especially VII)involvement • Recovery beginning within 4 weeks after progression stops • Autonomic dysfunction • No fever at onset • Increased CSF protein after 1week • CSF white blood cell count≤10∕μl • Nerve conduction slowing or block by several weeks
• Against diagnosis • Markedly asymmetric weakness • Bowel or bladder dysfunction (at onset or persistennt) • CSF white blood cell count>50 or PMN count>0/μl • Well-demarcated sensory level
• Excluding diagnosis • Isolated sensory involvement • Another polyneuropathy that explains clinical picture
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In the past, the principal diseases to be differentiaed from the Guillain-Barre syndrome were diphtheritic polyneuropathy and acute anterior poliomyelitis. Both are now rare in the United States. Diphtheritic polyneuropathy can usually be distinguished by the long latent period between the respiratory infection and onset of neuritis, the frequency of paralysis of accommodation, and the relatively slow evolution of neuritic symptoms. Acute anterior poliomyelitis can usually be
• distinguished by the asymmetry of the paralysis and by the presence of signs of meningeal irritation, fever, and CSF pleocytosis early in the course. Porphyricneuropathy resembles the Guillain-Barre syndrome clinically, but can often be differentiated by history of recurrent abdominal crises, mental symptoms, and onset following exposure to barbiturates or other drugs. Laboratory tests reveal the presence of delta-aminolevulinic acid and porphobilinogen in the urine. CSF
• protein content is not increased. Development of a Guillain-Barre-like syndrome during prolonged parenteral feeding should raise the possibility of hypophosphatemia-induced neural dysfunction. Toxic neuropathies associated with hexane inhalation or thallium or arsenic ingestion occasionally have an acute or subacute onset. These can be distinguished from the.Guillain-Barre syndrome by history of toxin exposure and, in the case of thallium, by subsequent
• development of alopecia. Botulism may be difficult to discriminate on clinical grounds from purely motor forms of Guillain-Barre syndrome, but electrophysiologic tests in botulism reveal normal nerve conduction velocities and a facilitating response to repetitive nerve stimulation. Tick paralysis should be excluded by careful examination of the scalp.
• Treatment: • No specific therapies are available. Plasmapheresis appears to reduce the time required for recovery and may decrease the likelihood of residual neurologic deficits. It is best instituted early, and it is indicated especially in patients with a severe or rapidly progressive deficit or respiratory
• compromise. Intravenous immunoglobulin (400/Kg/d for 5 days) appears to be equally effective and should be used in preference to plasmapheresis in adults with cardiovascular instability and in children; the two therapies are not additive.
• Glucocorticoid administration does not shorten the course or affect the prognosis. Mechanically assisted ventilation is sometimes necessary, and precautions against aspiration of food or stomach contents must be taken if oropharyngeal muscles are affected. Exposure keratitis must be prevented in patients with facial diplegia. •
• Prognosis: • Symptoms and signs cease to progress by about 4 weeks into the illness. The disorder is self-limiting, and improvement occurs over the weeks or months following onset. About 70 ～ 75% of patients recover completely, 25% are left with mild neurologic deficits, and 5% die, usually as a result of respiratory failure. The prognosis is poorer when there is
• evidence of preceding Campylobacter jejuni infection, and a more protracted course and less complete recovery are also likely when axonal degeneration rather than demyelinnation is the primary pathology. Advanced age, the need for ventilatory support, or more rapid onset of symptoms may also predict a poorer prognosis.
• In Landry's paralysis, or acute ascending paralysis: there is an asecending motor
• deficit, usually with sensory changes which are lessmarked. This syndrome may be caused by an actual inflammatory disease of the spinal cord, predominantly the anterior horn regions, or it may be associated with a polyradiculoneuritis (Landry--Guillain-Barre syndrome). In anterior poliomyelitis the inflammatory process is limited largely to the anterior horn cells, and there is a focal flaccid paralysis, segmental in distribution, with resulting atrophy. There is
• loss of both motor power and reflex action in the segments involved by the area of inflammation, often with associated vasomotor involvement, but no sensory changes. A meningeal reaction, with a pleocytosis in the cerebrospinal fluid, accompanies the process. • Meningeal inflammation may be accompanied by spinal cord involvement in the absence of transverse myelitis; adhesive spinal arachnoiditis usually causes both
• localized and disseminated changes. Cervical hypertrophic pachymeningitis produces focal manifestations suggestive of an extradural neoplasm; there may be associated pain and muscle spasm, sensory changes, and spinal subarachnoid block. A spinal epidural abscess may present symptoms of a focal, spaceoccupying, extramedullary lesion; there are usually associated signs of infection. While Pott's disease may cause cord symptoms, they are more often those of compression than of
• infection. Infections of the intcrvertebral disks callsc pain and signs of systemic infection, but rarely cause spinal cord involvement. With all of these extramedullary inflammations, signs of spinal cord disease, if they occur, may be the result of an interference with the blood supply rather than of an extension of the infectious process.