Search Cidpusa web EMG NCV |JULY 4, 2020
HandBook of polyneuropathy
CIDP: Pathophysiology
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study, CIDP occurred within a few weeks after an infectious event in 16% of the patients
*Because of the insidious onset, documenting precipitating illnesses or events is very difficult
*Both respiratory and gastrointestinal infections have been cited, but no causative organism has been identified
*With Guillain-Barre syndome, the most common preceding infection is Campylobacter
*The classical picture that suggests CIDP iS the presence of proximal (Shoulder and hip) and distal ( Hand and foot) weakness, with large fiber sensory
loss and reduced or absent reflexes.
*Few patients present with classic symtpoms.
*Some authors have suggested subclassifications based on the clinical varied clinical presentation in order to aid in diagnosis and treatment
*Currently these subclasses are not thought to be distinct diseases
CIDP: Regional Variants
Lewis-Sumner syndrome : (LSS) is a dysimmune peripheral nerve disorder, characterized by a predominantly distal, asymmetric weakness mostly affecting the upper limbs with sensory impairment, and by the presence of multifocal persistent conduction blocks.
Multifocal Motor Neuropathy is an autoimmune disease in which
patients begin producing antibodies against GM1 ganglioside, a lipid present on nerve fibers. These antibodies are rarely present in any other disease or in normal patients. In Multifocal Motor Neuropathy there is marked weakness caused by disrupting the nerves ability to conduct electricity producing, a syndrome known as conduction block. Conduction block can be demonstrated by EMG/NCS. The weakness typically begins in the hands and can make people unable to care for themselves. Over time, the weakness can spread to involve the legs and feet causing patients to be confined to wheelchairs.
Multifocal demyelinating neuropathy with persistent conduction block The
chronic motor involvement associated with fasciculations and cramps, mainly in the arms, led, in most patients, to an initial diagnosis of motor neuron
disease. In some patients (nine of 24), there was no appreciable muscle atrophy. Tendon reflexes were often absent or weak. The finding of persistent
multifocal conduction block confined to motor nerve fibres raises questions about the nature and the importance of this syndrome. Segmental reduction of
motor conduction velocity occurred at the site of the block, but significant slowing of motor nerve conduction was not found outside this site. The
response to intravenous IVIg treatment seems to be correlated with the absence of amyotrophy. Patients with little or no amyotrophy had an initial and
sustained response to IVIg, and did not develop amyotrophy during the follow up study.
*Distal CIDP M-proteins were present in 22% of patients with CIDP. There were no features that distinguished clearly between CIDP patients with or without an
M-protein, and nearly all of these patients responded to immunomodulating therapy. In contrast, nearly two-thirds of the patients with DADS neuropathy had immunoglobulinM (IgM) kappa monoclonal
gammopathies, and this specific combination predicted a poor response to immunomodulating therapy. Antimyelin-associated glycoprotein (anti-MAG) antibodies were
present in 67% of these patients
*Distal acquired demyelinating sensory neuropathy and sensory CIDP. Sensory CIDP patients had gait ataxia, large fiber sensory loss, and paresthesias,
and nine had frequent falls. The disease course was chronic and progressive (median duration 5 years, range 3 months to 18 years. Can present with a sensory ataxia .Sensory CIDP may present as
cryptogenic sensory polyneuropathy with normal or axonal electrophysiologic features.
*ANTI-MAG (Myelin Associated Glycoprotein) Neuropathy Patients with polyneuropathy and antibodies to myelin-associated glycoprotein (MAG) and sulphated glucuronyl paragloboside (SGPG) differ from chronic inflammatory demyelinating polyneuropathy (CIDP)
because of a slower, progressive course, symmetrical and predominantly sensory involvement of legs, predominantly distal slowing of motor conductions, and poorer response to therapy
*CIDP with Hypertrophic nerves
*Subacute demyelinating polyneuropathy
*Chronic Inflammatory demyelinating neuropathies
CIDP: Associated Conditions
*Most frequently CIDP is an idiopathic illness
*Has been known to occur with several conditions
*In these cases, the associated condition is included in the main
diagnosis to separate those cases from the idiopathic variety
*Example: CIDP
with HIV infection
*HIV infection
Mild lymphocytic pleocytosis and
increased gamma globulin level in the CSF are seen frequently
*Hodgkin lymphoma
*Associated neuropathy is not caused by direct infiltration of the peripheral
nerves but is a consequence of the autoimmune cascade that occurs with this disease, but the mechanism is not completely clear