Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired autoimmune disease of the peripheral nervous system characterized by progressive weakness and impaired sensory function in the legs and arms. The disorder is sometimes called chronic relapsing polyneuropathy (CRP) or chronic inflammatory demyelinating polyradiculoneuropathy (because it involves the nerve roots). CIDP is closely related to Guillain–Barré syndrome and it is considered the chronic counterpart of that acute disease. Its symptoms are also similar to progressive inflammatory neuropathy. It is one of several types of neuropathy.
Types
Several variants have been reported. Specially important are: An asymmetrical variant of CIDP is known as Lewis-Sumner Syndrome or MADSAM (multifocal acquired demyelinating sensory and motor neuropathy). A variant with CNS involvement named combined central and peripheral demyelination (CCPD). This variant is special because it belongs at the same time to the CIDP syndrome and to the multiple sclerosis spectrum. These cases seem to be related to the presence of anti-neurofascin autoantibodies.
Causes
Chronic inflammatory demyelinating polyneuropathy (or polyradiculoneuropathy) is considered an autoimmune disorder destroying myelin, the protective covering of the nerves. Typical early symptoms are "tingling" (sort of electrified vibration or paresthesia) or numbness in the extremities, frequent (night) leg cramps, loss of reflexes (in knees), muscle fasciculations, "vibration" feelings, loss of balance, general muscle cramping and nerve pain. CIDP is extremely rare but under-recognized and under-treated due to its heterogeneous presentation (both clinical and electrophysiological) and the limitations of clinical, serologic, and electrophysiologic diagnostic criteria. Despite these limitations, early diagnosis and treatment is favoured in preventing irreversible axonal loss and improving functional recovery.
There is a lack of awareness and treatment of CIDP. Although there are stringent research criteria for selecting patients for clinical trials, there are no generally agreed-upon clinical diagnostic criteria for CIDP due to its different presentations in symptoms and objective data. Application of the present research criteria to routine clinical practice often misses the diagnosis in a majority of patients, and patients are often left untreated despite progression of their disease.
CIDP has been associated with diabetes mellitus, HIV infection, and paraproteinemias.
Variants with paranodal autoantibodies
Some variants of CIDP present autoimmunity against proteins of the node of Ranvier. These variants comprise a subgroup of inflammatory neuropathies with IgG4 autoantibodies against the paranodal proteins neurofascin-155, contactin-1 and caspr-1.
These cases are special not only because of their pathology, but also because they are non-responsive to the standard treatment. They are responsive to Rituximab instead.
Also some cases of combined central and peripheral demyelination (CCPD) could be produced by neurofascins.
Autoantibodies of the IgG3 Subclass in CIDP
Autoantibodies to components of the Ranvier nodes, specially autoantibodies the Contactin-associated protein 1 (CASPR), cause a form of CIDP with an acute "Guillain-Barre-like" phase, followed by a chronic phase with progressive symptoms. Different IgG subclasses are associated with the different phases of the disease. IgG3 Caspr autoantibodies were found during the acute GBS-like phase, while IgG4 Caspr autoantibodies were present during the chronic phase of disease.
Diagnosis and symptoms
Diagnosis is typically made on the basis of presenting symptoms in tandem with electrodiagnostic testing or a nerve biopsy. Doctors may use a lumbar puncture to verify the presence of increased cerebrospinal fluid protein.