Presentation and course
Acute inflammatory demyelinating polyneuropathy. Guillain-Barré syndrome is now recognized to be a diverse disorder that can be divided into several patterns based on the predominant mode of fiber injury (demyelinating vs. axonal) and on nerve fibers involved (motor, sensory and motor, cranial). The most frequent pattern in Western countries is the acute inflammatory demyelinating polyneuropathy. The major complaint is weakness, which usually evolves symmetrically over a period of several days. Evolution is complete after 2 weeks in 50% of cases, after 3 weeks in over 80%, and after 4 weeks in over 90% (02). In most instances, weakness is noticed initially in the legs, but it can begin in the arms or the face. The severity of weakness varies from mild gait difficulty to total paralysis with death from respiratory failure. Aside from facial diplegia, which is found in at least half of the cases, involvement of extraocular muscles has been described. Other symptoms include pain and muscle aches, which occur in 30% to 55% of cases. Early in the course of illness, subjective dysesthesias and paresthesias are common. At later times, objective sensory loss can be demonstrated in three-fourths of cases. Tendon reflexes are usually abolished or diminished. Dysautonomia is common and can manifest as heart rate or blood pressure instability, blood pressure fluctuations, pupillary dysfunction, and bowel or bladder dysfunction (02). Acute inflammatory demyelinating polyneuropathy is a monophasic illness, though treatment-related fluctuations or relapses occur in a minority of patients (37).
Variants of Guillain-Barré syndrome. Axonal involvement in Guillain-Barré syndrome has traditionally been considered secondary to severe demyelination until Feasby and colleagues called attention to a small group of patients that had primary axonal degeneration, now termed acute motor-sensory axonal neuropathy. These patients typically have severe, fulminant paralysis, sensory loss, and incomplete recovery. Autopsy findings demonstrate axonal degeneration without demyelination and with minimal inflammation (12).
In comparison, acute motor axonal neuropathy, also called “Chinese paralytic syndrome,” is characterized by acute weakness or paralysis without sensory loss and is closely associated with antecedent Campylobacter infection. Patients with acute motor axonal neuropathy usually have a more rapid progression and an earlier nadir than those with acute inflammatory demyelinating polyneuropathy (16). A subset of patients with acute motor axonal neuropathy recovers rapidly. Electrodiagnostic studies confirm the selective involvement of motor fibers with preservation of sensory responses. High titers of IgG anti-GM1, GM1b, or GD1a antibodies are more common in the acute motor axonal neuropathy than in acute inflammatory demyelinating polyneuropathy (17). These antibodies cause a pathophysiological spectrum ranging from reversible conduction block to axonal degeneration of motor fibers (24).
A third disorder considered as a Guillain-Barré syndrome variant is Fisher syndrome, which is characterized by ophthalmoplegia, ataxia, areflexia, and association with antibodies that recognize the ganglioside GQ1b, GT1a, or GD3 (49). Facial nerves may be involved in addition to ocular motor nerves, but limb weakness is infrequent. Another condition that is associated with anti-GQ1b antibody is Bickerstaff brainstem encephalitis, which is characterized by a disturbance of consciousness, hyperreflexia, ataxia, and ophthalmoplegia (31). Brain MRI is abnormal in 30% of these patients. The prognosis for recovery is good. Some patients have concomitant limb weakness and electrodiagnostic evidence of an axonal subtype of Guillain Barré syndrome (31). The immunological profile in Bickerstaff brainstem encephalitis and Fisher syndrome suggests common pathogenetic mechanisms, but the nosological relationship between these disorders remains controversial.
Other variants of Guillain Barré syndrome include pharyngeal-cervical-brachial variant, acute pandysautonomia, and sensory Guillain-Barré syndrome. The pharyngeal-cervical-brachial variant manifests as dysphagia, neck and shoulder muscle weakness, and may be associated with IgG anti-GT1a antibody (22). In the sensory form of Guillain-Barré syndrome, patients have acute sensory loss but no weakness although demyelinating features are present in motor nerve conduction studies (32). Acute/subacute pandysautonomia without concomitant motor or sensory deficits is rare and is associated with antibody against ganglionic acetylcholine receptor in some cases.
Two sets of criteria are often used for the diagnosis of Guillain-Barré syndrome: NINDs criteria and Brighton collaboration (02; 39). The Brighton Collaboration Consensus criteria and recently published guideline on the diagnostic criteria are listed in tables 1 and 2 (45).
Table 1. Brighton Collaboration
|
Diagnostic criteria |
Level of diagnostic certainty |
1 |
2 |
3 |
|
Bilateral and flaccid limb weakness |
+ |
+ |
+ |
|
Decreased or absent reflexes in weak limbs |
+ |
+ |
+ |
|
Monophasic course and interval between onset and nadir of 12 hr to 4 weeks |
+ |
+ |
+ |
|
Cytoalbuminologic dissociation in CSF |
+ |
+/-* |
- |
|
Nerve conduction studies consistent with Guillain Barré syndrome |
+ |
+/-** |
- |
|
Absence of alternative diagnosis for weakness |
+ |
+ |
+ |
*CSF cell count less than 50 cells/µl with or without elevated protein ** If CSF results are not available, nerve conduction studies must be consistent with Guillain Barré syndrome. (40) |
Table 2. Diagnostic Criteria for Motor-Sensory or Motor Guillain-Barré Syndrome (GBS)
Features required |
|
• Progressive weakness of arms and legs |
|
• Tendon reflexes absent or decreased in affected limbs |
|
• Progressive worsening for no more than 4 weeks |
Features strongly supportive of the diagnosis |
|
• Relative symmetry |
|
• Relatively mild /absent sensory symptoms and signs |
|
• Cranial nerve involvement especially bilateral facial weakness |
|
• Autonomic dysfunction |
|
• Respiratory insufficiency (due to muscle weakness) |
|
• Pain (muscular or radicular in back or limb) |
|
• Recent history of infection (< 6 weeks), (possibly also surgery) |
Laboratory findings that support the diagnosis |
|
• CSF: increased protein; normal protein does not rule out diagnosis; (WBC < 5 white cells/mm3) |
|
• Blood: Anti-GQ1b antibodies usually present in Miller Fisher syndrome |
|
• Electrodiagnosis: Nerve conduction studies (NCS) consistent with polyneuropathy. NCS may be normal during first few days of disease. |
(45) |
Prognosis and complications
Recovery ranges from complete and rapid to slow with significant residual disability, depending on the relative proportions of segmental demyelination and axonal degeneration in patients with acute inflammatory demyelinating polyradiculoneuropathy. Most patients recover spontaneously with 80% ambulating independently at 6 months after disease onset (07). Between 3% and 8% of patients die from complications. Permanent disabling weakness, imbalance, or sensory loss occurs in 5% to 10%, whereas mild residual signs of neuropathy persist in 50% of patients. Little or no further recovery can be expected after 2 years.
Approximately 3% of patients with acute inflammatory demyelinating polyradiculoneuropathy suffer one or more recurrences. The clinical symptoms of relapses do not differ from those of the acute monophasic form of the disease. Each episode is characterized by rapid onset of symptoms over a few days, with subsequent complete or near-complete recovery. In patients with multiple relapses, nerves may become palpably enlarged. Such cases are to be distinguished from chronic inflammatory polyradiculoneuropathy, which evolves over many weeks, months, or years.
Clinical vignette
A 40-year-old nondiabetic woman presented to the emergency room with weakness of her legs that had started 5 to 6 days earlier and had begun to involve her upper extremities. Tingling and numbness of her toes and fingertips accompanied her symptoms. The patient had a flu-like illness 2 weeks before the onset of symptoms and no history of tick bites. Exam showed mild facial weakness, 4/5 strength in her proximal muscles and 3+/5 in her distal muscles, slightly decreased light touch and pinprick sensation distally, and absent deep tendon reflexes throughout. Her CSF showed elevated protein (150 mg/dl) with no cells. Nerve conduction studies showed normal compound motor action potential amplitudes, mildly slowed conduction velocities, but prolonged distal motor and F wave latencies. Her forced vital capacity was 2 L. She improved significantly after a course of plasmapheresis.