Resolving the treatment conundrums of CIDP

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is as complicated to articulate, as it is to manage. CIDP is the result of an inflammatory attack against myelin, the fatty layer that encases large nerves. The damage to the myelin sheath considerably slows down the speed at which nerves transmit electrical impulses. This leads to limb weakness, sensory impairment, and a host of other symptoms.

The diagnosis of CIDP is made on the basis of a clinical examination, nerve conduction studies (NCS), spinal fluid analysis, and countless blood tests. If this convoluted diagnostic process is hair-tearing, the treatment is even more perplexing.

There are 2 major CIDP treatment conundrums. The first is whether to start the treatment with steroids, or with intravenous immunoglobulins (IVIg). The second conundrum is what to do when the patient fails to respond to both of these first line CIDP treatments. Two recent papers have now come to the rescue, and they hope to settle, once and for all, these two major neurological puzzles.

1. Choosing steroids or IVIg as 1st line treatment

The first line treatment for CIDP is usually a toss-up between steroids and intravenous  immunoglobulins (IVIg). This is because neurologists had no way of telling who will do well on steroids, and who will respond to IVIg. Until now, that is. A recent report in the Journal of Neurology, Neurosurgery and Psychiatry (JNNP) set out to understand what patient characteristics predict response to IVIg. The authors studied >200 people with CIDP treated with IVIg, and reported that 1/4 did not respond. These IVIg non-responders had the following features:

• The presence of pain
• Association with other autoimmune diseases
• A difference in the severity of weakness between the arms and the legs
• The absence of anti-myelin associated glycoprotein (anti-MAG)

The authors conclude that people with CIDP who have the features above should start their treatment with steroids rather than IVIg. This surely beats tossing a coin.

2. Choosing rituximab as 1st line treatment

Choosing the 2nd line treatment of CIDP is comparatively easy; swap between IVIG and steroids, or go for plasma exchange (PE). Rituximab, a monoclonal antibody, is now also recognised as an effective treatment for CIDP. Conventional practice is to use this expensive treatment only when both IVIg and steroids fail. A recent paper however suggests that people with CIDP who also have IgG4 antibodies do not respond to either IVIg or steroids. On the bright side however, they do well when treated with Rituximab. The paper in the journal Neurology is titled Rituximab in treatment-resistant CIDP with antibodies against paranodal proteins. The authors studied only 4 patients, but the number was enough for them to suggest that patients with CIDP, who also have IgG4 antibodies, should be treated with Rituximab. Makes sense to me, if the alternative is predictable failure.

Now that some light has been shone on the treatment of CIDP, the next stage is to see how things work at the coal face. Do you have any feedback on CIDP treatment? Please leave a comment.

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