N.C.V. in Demylinating neuropathy

-Critical test to determine whether the disorder is truly a peripheral neuropathy and whether the neuropathy is demyelinating (demylinating means that the myelin covering the axon has been damaged. Testing is done by a nerve conduction velocity test or NCV. Following results prove that Myelin has been lost.

1-Prolonged distal latencies

2-Absent or prolonged F wave latencies .

3-Findings of a demyelinating neuropathy are slow Nerve conduction Velocity with a preserved amplitude. The NCV will be slower then 35 m/s.

4-Prolonged CMAP which is known as Temporal-Dispersion.

5- Conduction Block is the term used when the CMAP is lower amplitude in proximal stimulation and increases in size in distal stimulation.

Axonal Neuropathy -Multifocal conduction block or temporal dispersion of compound muscle action potential - -Variable conduction slowing to less than 70% of normal -Absent or prolonged F wave latencies and low amplitude.- As the disease progresses, patients tend to develop secondary axonal degeneration

 (A skin biopsy should be considered  do not recommend a nerve biopsy) -Indications for Biopsy -Patients in whom the diagnosis is not completely clear -Cases where other causes of neuropathy (eg, hereditary, vasculitic) cannot be excluded -Case where profound axonal involvement is observed on EMG --Interstitial and perivascular infiltration of the endoneurium with inflammatory T cells and macrophages with local edema -Evidence exists of segmental demyelination and remyelination with occasional onion bulb formation, particularly in relapsing cases -Some evidence of axonal damage also is observed, with loss of myelinated nerve fibers-

The inflammatory infiltrate with neutrophil infiltration is observed in only a minority of patients CIDP:

Histology Demyelinated fibers (D) -Fibers undergoing active macrophagemediated demyelination (M)

 - First line treatments-  -IVIG has been shown to best efficacy as IVIg in treatment of CIDP / MMN

--3 plasma exchanges can be used per week for first 2 weeks -Additional treatment is determined by clinical response . Steroids may work well too! Rituxan will work in cases that IVIG cannot help in.

IVIG -Solution composed mostly of heterogenous human IgG but also small amounts of IgA and IgM --IVIg contains random set of antibodies that would neutralize immune factors, causing damage to peripheral nerve in CIDP -Activates complement cascade and provides multitude of antibodies capable of neutralization of many microorganisms, toxins, viruses, and presumably autoantibodies -On average, improvement seen by day 10 and continues through day 4 -Serum half-life is approximately 21-29 days -Patients usually require repeated treatments every few weeks or months to maintain remission or treat recurrences

Agents used for refractory patients -

 1-Cyclosporine (Sandimmune, Neoral) --

2- Cyclophosphamide (Cytoxan) -

3-Azathioprine (Imuran)-

4-Mycophenolate (CellCept)-
Several controlled studies confirmed benefit The outcome of CIDP is difficult to predict owing to the variety of clinical patterns and evolution -

If left untreated, it can become disabling, with loss of ability to ambulate, work, or function independently

Prognosis:

The long term prognosis of CIDP patients was generally favorable, but 39% of patients still required immune treatments and 13% had severe disabilities. Mode of onset, distribution of symptoms, and electrophysiological characteristics may be prognostic factors for predicting a favorable outcome.

continued to CIDP- PAGE Chronic inflammatory demyelinating polyneuropathy

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