Corticosteroids, surprisingly, worsen the long term outcomein GBS when given alone (level 1a evidence), perhaps because any beneficial effect is balanced by a detrimental effect on denervated muscle. However, a recent Dutch trial suggests the combination of intravenous methyl prednisolone (500 mg/day forfive days) followed by IVIg hastens recovery slightly more than IVIg alone. The use of corticosteroids will need to be re-evaluated when the trial has been published and the results incorporated into the systematic review.
Situations for which evidence is lacking
Most published trials excluded children, patients with very mild GBS, and those seen more than two weeks after onset. There is therefore no evidence for treatment in these groups. The expected benefit needs to be considered against the risk of adverse effects and cost. Mildly affected patients usually recover well without treatment, though one third have residual symptoms at six months. The response to treatment is generally less in patients treated later, but we usually treat patients presenting beyond two weeks if they are still deteriorating (level 4 evidence) .None of the trials was statistically designed to prove whether different treatments were more effective in subtypes of GBS, and we recommend that all subtypes are treated similarly, although the results from small subgroups suggest that IVIg might be better than PE for patients with axonal GBS, motor GBS or antibodies to ganglioside GM1. If a patient has not improved at all two weeks after treatment then it seems reasonable to try another course of the same or different treatment, especially if neurophysiological conduction block is still present. About 10% of patients experiencea temporary clinical relapse a few weeks after initial improvement. This may be because the treatment has worn off before the underlying disease has subsided, and does not necessarily mean the patient will develop CIDP. Most clinicians give a repeat course of the same treatment if the relapse is severe (level 4 evidence).
General supportive management
The most common causes of death in GBS are still respiratory failure, cardiovascular disturbance, and thromboembolism. Outcome is better for patients managed in specialist neurology centres than district general hospitals. The vital capacity is the most useful measure of respiratory muscle weakness, and if this falls below 20 ml/kg (approximately 1500 ml for an average adult) then urgent referral to an intensive care unit should be made. Do not wait for a fall in arterial oxygen saturation or symptoms of breathlessness, which are very late signs indicative of imminent death. Patients with rapid worsening, bulbar weakness or autonomic dysfunction are more likely to need ventilation. Sympathetic and parasympathetic hyper- or hypoactivity may cause cardiac brady- or tachyarrhythmias and rapid fluctuations in blood pressure. Tracheal suctioning risks triggering bradycardia or asystole which can be prevented by hyperoxygenation beforehand. A cardiacpacemaker is rarely needed. All patients should have continuous ECG monitoring until they are clinically improving and the tracheostomy is removed. Low dose subcutaneous heparin is recommended for prophylaxis of venous thromboembolism. Neuropathic and radicular pain are common, and have traditionally been treated with convention alanalgesics, amitriptyline or carbamazepine. A recent placebo controlled trial has provided strong evidence for the efficacy of gabapentin 500 mg twice daily. Physiotherapy is useful toavoid contractures and aid mobilisation. Many patients become depressed.
Outcome
After one year, about 5% of GBS patients have died and 15% are still unable to walk unaided. Factors associated with poor outcome are older age, preceding diarrhoeal illness, more severe weakness, rapid onset, electrically in excitable nerves, and muscle wasting. Chronic fatigue is common even in those who recover normal muscle power. Even after between three and six years, over one third still have lifestyle alterations, and half have residual muscle aches and cramps (related to sensory deficit).
Miller Fisher and related syndromes
Miller Fisher syndrome (MFS) is clinically defined by acute ataxia, ophthalmoplegia, and areflexia. Facial weakness and pupillary abnormalities are common. The index cases had no limb weakness. There is some inconsistency in published studies as to whether cases with limb weakness should be called MFS or Miller Fisher/Guillain-Barré overlap syndrome (our preference). The frequency of MFS is about 1–5% of GBS, but higher in Asia. There are no randomised trials of treatment in MFS, but outcome is almost always good even without treatment, and probably only those with limb weakness require treatment as for GBS. In a recent series of 50 patients with MFS, almost all were completely asymptomatic at six months, whether or not they had received plasma exchange.
Bickerstaff’s brainstem encephalitis differs from MFS in having altered consciousness, extensor plantar responses,and CSF pleocytosis. Wernicke’s encephalopathy is an important differential diagnosis. There are no trials of treatment but spontaneous recovery is usual, so that it is difficult to assess reports of benefit from PE or IVIg.
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