Paraproteinaemic Demyelinating Neuropathy.

What is PDN ?

Professor Hugh Willison of Glasgow, Scotland said at a UK conference, "Paraproteinaemic Demyelinating Neuropathy" is a major cause of late onset demyelinating neuropathy, very similar to CIDP though more chronic. It mostly affects people of 60 years and over. Patients have many symptoms to contend with. Unfortunately it tends to be a long-term illness."

PDN happens through a neurological malfunction, brought about by a wrong action of the immune system. It is acquired and not inherited, viral or infectious. Nor is it a "nervous disorder". The neuropathy is related to other disorders in the inflammatory, demyelinating neuropathy family, such as Guillain-Barré Syndrome (GBS) and CIDP (Chronic Inflammatory Demyelinating Polyneuropathy). It has also been described variously under several titles as listed on the index page, including "MGUS-associated neuropathy", "a chronic demyelinating neuropathy associated with a benign paraprotein" and "CIDP associated with paraprotein". The CIDP connection is because some neurological experts, like Professor Hugh Willison, regard the clinical, electrophysiological (a form of diagnostic testing) and pathological features of many PDN cases as closely similar to Chronic Inflammatory Demyelinating Polyradiculoneuropathy - CIDP.

However there are significant diagnostic differences . Notermans NC et al. (Jan 2002) reported that in 29 PDN (MGUS associated polyneuropathy) patients sensory symptoms and signs predominated, there was usually no cranial nerve involvement, and the neuropathy was symmetrical with a slowly progressive course. In the 30 CIDP patients a preceding infection was frequent, motor features predominated, there was often cranial nerve involvement and the neuropathy could be assymetrical. Yet all 59 patients fulfilled research criteria for CIDP.

WHAT IS PARAPROTEIN/Monoclonal Gammopathy? Paraprotein is the presence in the blood/serum of an abnormal amount of any single type of protein/antibody/immunoglobulin. The plasma cells of the bone marrow normally produce correct amounts of the antibodies, or proteins or immunoglobulin that help the body to fight infection. Rarely, an excess amount or paraprotein is produced. This is often referred to as M protein or in North America as "an M spike". Paraprotein is present in a very small percentage of people, especially as they get older. About 0.1% in the 3rd decade have paraprotein but it rises to 1% of healthy people over 50 and then to some 3- 5% of people in the 70 plus age group. It can be present in 10% of over 75's and as high as 20% of people in their 90's.

WHAT CAUSES THE PARAPROTEIN? The anti-body producing plasma cells in the bone marrow or lymphoid organs have gone out of control. They have expanded to form benign or malignant tumours. These are, so to speak, locked in an "on" position and secrete or spew out clones of the same, single antibody (or immunoglobulin). This process is known as Monoclonal Gammopathy.

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Please note. These notes are based solely on my own experience and my layman's reading of published professional neurology material. They should not be understood as coming from any personal medical expertise. Should any professional neurologist, or anyone else for that matter, spot a terrible error please inform me!





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