@gailannr
I found this explanation: What is CIDP?
In CIDP, the immune system mistakenly targets and attacks the protective tissue, called myelin, that covers the nerves in the arms and legs. Over time, as the myelin wears away, nerves lose their ability to send signals, leading to muscle weakness or impaired motor function.

The letters CIDP stand for chronic inflammatory demyelinating polyradiculoneuropathy. Let’s break down what each word means.

Chronic means the condition progresses over time and doesn’t go away without treatment.
Inflammatory refers to the cause of your symptoms. With CIDP, the immune system’s inflammatory cells mistakenly recognize nerve tissue as foreign, sending cells to attack it.
Demyelinating describes the nerve damage. Think of your nerves as copper wires. “The damage is mostly happening to the insulation of the wire — and not as much to the wire inside,” says Divyanshu Dubey, M.B.B.S., a neurologist and specialist in CIDP treatment at Mayo Clinic. This protective covering is called myelin. So, as the immune system attacks this tissue, it demyelinates the nerves.
Polyradiculoneuropathy describes where in the body the damage is happening. “Poly” is Greek for “many”; “radiculo” means “root”; “neuro” is Greek for “nerve”; and “pathy” is Greek for “disease.” Specifically, the term refers to nerve disease in the arms and legs.