Haymaker and Kernohan (1949), who stressed that edema of the nerve roots was an important change in the early stages of the disease. Subsequently, Asbury and colleagues (1969) established that the essential lesion, from the beginning of the disease, was perivascular mononuclear inflammatory infiltration of the roots and nerves. More recently, it has been found that complement deposition on the myelin surface may be the earliest immunologic event. For details of the historical and other aspects of this disease, see the monographs by Ropper and colleagues (1991) and by Hughes (1990).
The incidence of GBS has varied between 0.4 and 1.7 cases per 100,000 persons per year; the median taken from several studies is 1.1 and may be most dependable. It is generally a nonseasonal and nonepidemic disease, but outbreaks have been recorded in rural China following exposure of children to C. jejuni through chicken feces deposited in rice paddies. Women appear to be slightly more susceptible. The age range in our series has been 8 months to 81 years, with attack rates highest in persons 50 to 74 years of age. Cases are known in infants and in the very aged.
In addition to a seasonal increase in incidence after natural influenza outbreaks, the administration of the
A/New Jersey (swine) influenza vaccine, given in the United States in late 1976, brought attention to a slight increase in postvaccinal incidence of GBS. Several, but not most subsequent influenza vaccination programs have been associated with a marginal increase in cases. Representative was the widely publicized worldwide H1N1 vaccination program, in which the calculated risk of developing GBS after vaccination was in the range 2 cases per 1 million doses of vaccine, barely above the baseline rate and appearing mostly in individuals over 50 years (De Wals et al). GBS appears in temporal relationship to almost all other vaccinations, but the association in these instances may be idiosyncratic and infrequent. Trauma and surgical operations may precede the neuropathy, but a causal association to them also remains uncertain.
The typical case is readily identified. Paresthesias and slight numbness in the toes and fingers are the earliest symptoms; only infrequently are they absent throughout the illness. The major clinical manifestation is weakness that evolves more or less symmetrically over a period of several days to a week or two, or somewhat longer. The proximal as well as distal muscles of the limbs are involved, usually the lower extremities before the upper (thus the older term Landry ascending paralysis); the trunk, intercostal, neck, and cranial muscles may be affected later. Weakness progresses in approximately 5 percent of patients to total motor paralysis with respiratory failure within a few days. In severe cases, the ocular motor nerves are paralyzed and even the pupils may be unreactive.
More than half of the patients complain of pain and an aching discomfort in the muscles, mainly those of the hips, thighs, and back. These symptoms precede weakness and may be mistaken for lumbar disc disease, back strain, and orthopedic diseases. A few patients describe burning in the fingers and toes, and if this appears as an early symptom, it may become a persistent problem. Despite sensory symptoms, sensory loss is variable during the first days and may initially be barely detectable so that the typical case has the character of a predominantly motor neuropathy. By the end of a week, vibration and joint position sense in the toes and fingers are usually reduced; when such loss is present, deep sensibility (touch-pressure-vibration) tends to be more affected than superficial (pain-temperature).