The clinical improvement that follows the administration of IVIg or plasma exchange usually cannot be readily discerned in an individual patient; that is, it is apparent only by comparing large groups of treated and untreated patients. For this reason it is not possible to judge that a patient who fails to improve or who worsens through the period of treatment has derived no benefit from therapy. The question nevertheless arises regarding further plasma exchanges or continued infusion of immune globulin in cases of continued worsening or lack of improvement. Further complicating the matter are the limited expectations for early improvement in cases of axonal GBS. Our advice has been to repeat either of the two immune treatments if a patient is clearly declining, particularly if there is evidence of demyelinating neuropathy on the NCS, and if the illness is not much longer than 4 weeks in duration. Performing plasma exchanges after the use of IVIg does not make sense to us (but this notion has not been tested); therefore, we either follow a series of exchanges with IVIg or, more often, repeat a course of IVIg as suggested by
Farcas and colleagues.
The value of corticosteroids alone in the treatment of GBS has been disputed for decades. Many clinicians were persuaded of their benefit; however, two randomized controlled trials, one with conventional-dose prednisolone and the other with high-dose methylprednisolone, have failed to demonstrate beneficial effect (Hughes, 1991). Although corticosteroids can no longer be recommended as routine treatment for acute GBS, we have observed a few instances in which the administration of intravenous high-dose corticosteroids seemingly halted the progress of an acute case.
As already indicated, approximately 3 to 5 percent of patients do not survive the illness, even in the best equipped hospitals. In the early stages, death is most often a result of cardiac arrest, sometimes related to dysautonomia, adult respiratory distress syndrome, pneumoor hemothorax, or some type of accidental machine failure. Later in the illness, pulmonary embolism and infectious complications of prolonged immobilization and respiratory failure are the main causes of death.
The majority of patients recover with mild motor deficits or sensory complaints in the feet or legs. In approximately 10 percent, however, the residual disability is pronounced; this occurs in those with the most severe and rapidly evolving form of the disease, when there has been evidence of widespread axonal damage and in those requiring early and prolonged mechanical ventilatory assistance. A fairly consistent predictor of residual weakness and muscle atrophy is the finding of greatly reduced amplitudes of muscle action potentials and widespread denervation, both indicative of axonal damage.
In patients with respiratory failure, the average period of machine-assisted respiration has been 22 days and the period of hospitalization approximately 50 days (these were twice as long prior to the introduction of plasma exchange and IVIg). As a rule, older adults recover more slowly than younger ones and children and have more residual weakness.
The most common remaining difficulties are weakness of the lower leg muscles, numbness of the feet and toes, and mild bifacial weakness. A few patients are left with sensory ataxia that tends to be severe and quite disabling. Distal neuropathic pain and persistent autonomic problems occur but are also infrequent. All manner of other late symptoms are attributed with little evidence to the illness and should be addressed on their own merits—fatigue and asthenia, muscle cramps, dizziness, pain, and breathlessness. Depression has not been frequent.
The speed of recovery varies, but its pace is steady. Often, it occurs within a few weeks or months; however, if axons have been damaged, their regeneration may require 6 to 18 months or longer. In our experience, little improvement can be expected in disabilities that have lasted 2 or more years.