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Go to page-4   You are on Page-3      go to page-2 Go to page -1 Journal of Neurology Neurosurgery and Psychiatry 2003;74:ii9 © 2003 MANAGEMENT OF INFLAMMATORY NEUROPATHIES Robert D M Hadden1 and Richard A C Hughes2 Clinical presentation The time course of CIDP may be relapsing–remitting, chronicprogressive, monophasic or have a GBS-like onset. Motor andsensory nerves are usually involved. Several variants are nowbeing recognised (box 3). Most of the inflammation occurs in the proximal roots. Symptoms are primarily caused by conduction block resulting from demyelination, which generally responds well to treatment. The degree of block of conduction may also be increased by physical factors such as temperature, ischaemia,and exercise, which can explain rapid fluctuations in symptoms. After some years of disease there is a gradual accumulation of axonal degeneration, clinically evident as wasted muscles, which is generally irreversible. In the later stages disability is caused by a combination of axonal degeneration and demyelination, and responsiveness to treatment gradually decreases. Half of all patients suffer temporary severe disability and 13% have a long term requirement for aids to walk. Factors associated with a better prognosis are younger age, relapsing–remittingcourse, and absence of axonal damage.

Box 3 Variants of chronic inflammatory demyelinating polyradiculoneuropathy

• Symmetrical sensory and motor CIDP
• Sensory CIDP
• Motor CIDP
• Multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy
• Multifocal motor neuropathy

Diagnosis and investigation
The diagnosis is made on the basis of nerve conduction studies. Conduction slowing and prolonged distal motor latencies occur in both CIDP and hereditary demyelinating neuropathy, but CIDP is distinguished by the presence of motor conduction block, temporal dispersion, and asymmetric involvement, indicating a multifocal process. F-responses are delayed and often absent. Such abnormalities should be present in at least three nerves to meet diagnostic criteria. Some nerves may appear to be normal or to have axonal neurophysiology, so the diagnosis may be missed if too few nerves are tested and proximal conduction block is not specifically sought. A nerve biopsy is sometimes diagnostic, but not necessary and now not routinely done. Most patients with CIDP have axonal degeneration without demyelination on sural nerve biopsy. Serum protein electrophoresis should be done initially and annually thereafter, because the development of a paraprotein may indicate an alternative diagnosis and treatment (see later). Measurement of serum autoantibodies is not usually helpful. The CSF protein is raised in at least 80% of patients. A minority of patients has evidence of coexistent asymptomatic CNS demyelination on magnetic resonance imaging or evoked potential examination.

Immune modulating treatment
Corticosteroids were the first accepted treatment but entered clinical practice without today’s high standards of evidence. Corticosteroids induce at least short term improvement in 65–95% of patients (level 1a and 4 evidence). There are many regimens. We prefer oral prednisolone 1.5 mg/kg on alternate days in a single morning dose with careful review and dose adjustment at two weekly intervals for 12 weeks, when a judgement needs to be made about whether to continue or switch to IVIg. Improvement begins after 1–4 weeks (but occasionally months), and reaches a plateau at about six months. Occasional patients deteriorate on steroids by an unknown mechanism, especially those with pure motor forms of CIDP or with multifocal motor neuropathy with conduction block. Prednisolone is cheap but has serious long term adverse effects. Osteoporosis prophylaxis should be started at the same time.

 

IVIg appeared efficacious in three of four randomised trials and the efficacy was supported by a meta-analysis level 1a evidence).Unfortunately its benefit lasts only 2–12 ^{Unfortunately its benefit lasts only 2–12 weeks, so that treatment has to be repeated and is very expensive. Approximately two thirds of patients respond, of whom one third improve and need no further treatment and two thirds require repeated courses. The initial dose should be 0.4 g/kg daily for five days (smaller doses were less effective), but maintenance doses can usually be reduced to 0.4–2.0 g/kg in total and given over 1–2 days. Crossover trials have shown no significant short term difference between IVIg and PE (courses of similar cost) or between IVIg and oral prednisolone}