In simple terms, CIDP is a term for chronic form of Gullian-Barre syndrome (GBS), which is described in a separate section. It is a condition of nerves caused by malfunction of body’s immune system.

What are symptoms of CIDP?

Its symptoms are somewhat similar to GBS, and mostly include numbness, weakness, dizziness, and unsteadiness. In a typical case of CIDP, weakness is generalized in arms and legs, and may be more so in proximal muscles than distal (hip or shoulder muscles than foot or hand). Unlike GBS, most patients do not have weakness of facial muscles or muscles involved in breathing. It can present as one illness progressively getting worse, or in fluctuating fashion with remission and relapses.

What exactly is the problem in CIDP?

Similar to GBS, it is a malfunction of immune system, but unlike GBS, mostly without preceding history of infection. Different parts of immune system, including cells and antibodies, cross-react and attack the outer covering of nerves, the myelin. This leads to an inflammatory reaction, which can destroy the covering, and the inside part of nerves (axon) if left untreated.

 

How is CIDP diagnosed?

CIDP is suspected in a patient with relatively quickly progressive weakness (in weeks to months), and examination findings suggestive of peripheral neuropathy. Investigations are done in following steps:

1. Basic labs are done to rule more common issues that can cause neuropathy, such as uncontrolled diabetes.
2. If no clue is found, an EMG/NCS (electromyogram and nerve conduction studies) is performed. In typical cases of CIDP, EMG/NCS reveals a pattern suggestive of demyelinating neuropathy (significantly delayed distal latencies and slowed conduction velocities, abnormal shape of dispersion of motor unit potentials, and relative sparing of sural responses).
3. Following labs are also performed, not each one in every case:

• Complete blood cell count (CBC)
• Sedimentation rate (ESR)
• Complete metabolic profile (CMP)
• Liver profile (LFTs)
• Thyroid function tests (TFTs)
• Vitamin B12, and methylmalonic acid levels
• Serum protein electrophoresis (SPEP)
• Urine protein electrophoresis (UPEP)
• Serum immunofixation (IF)
• Lyme test
• Syphilis test
• HIV test
• Covid-19 test

4. Lumbar puncture (LP) to analyze cerebrospinal fluid (CSF). In typical cases of CIDP, CSF protein level is significantly high. There may also be a few more white blood cells. Mild CSF protein elevation or too many white blood cells may suggest an alternate diagnosis. If 50 per cubic mm or more white cells are found, further analysis is done on CSF to rule out conditions like lymphoma, other type of cancer, sarcoidosis, or HIV.
5. Imaging with an MRI or ultrasound: these tests are not routinely performed but can provide meaningful data. Enlargement of affected nerves differentiate demyelinating neuropathy from smaller than normal nerves, which are seen in axonal neuropathy.
6. Nerve biopsy (may be needed in atypical cases)

 

Is there a single confirmatory lab test for CIDP?

Diagnosis of CIDP is based upon its symptoms, history, examination findings, electrical findings, and CSF results if available. Like many other conditions, its diagnosis is based upon pattern-recognition, instead of a single test. This is the reason that one should be careful about misdiagnosis or wrong diagnosis, which are not uncommon while dealing with CIDP.

 

How is CIDP treated?

Treatment of CIDP is similar to GBS, and is geared to tamper down body’s immune responses. Oral steroid (e.g., prednisone), intravenous immunoglobulins (IV-Ig), or plasma exchange are initial options. I start with oral prednisone in mild to moderate cases, and IV-Ig (with or without prednisone) in severe ones. I only use plasma exchange if prednisone and/or IV-Ig do not work. I tailor frequency of IV-Ig treatment based upon patient’s response and clinical course. Prednisone dose is also slowly lowered to a smallest effective dose. Many chronic CIDP patients re maintained on a small dose of prednisone, less than 5-10mg a week, with and without IV-Ig, for exacerbations. Subcutaneous injection of immunoglobulins, SC-Ig, if available is an attractive alternative to IV-Ig treatment, with significantly less logistical issues and potential side effects.

Some patients either do not respond to or do not tolerate steroid treatment. For those patients, alternate medications, usually called steroid sparing drugs, can be an option. List of these drugs include mycophenolate mofetil, azathioprine, cyclophosphamide, methotrexate, and cyclosporine. Evidence of their effectiveness is limited, and I usually try azathioprine or mycophenolate. In spite of all these options, some patients with a diagnosis of CIDP do not respond to the treatment. One reason for lack of response may be the incorrect diagnosis

 

Are there different types of CIDP?

 Many cases of CIDP do not follow the typical pattern described above. Some variations are as follows:

1. Sensory CIDP: mostly sensory symptoms with electrical evidence of motor nerve demyelination.
2. Chronic Immune Sensory Polyradiculapathy (CISP): Sensory symptoms (sensory ataxia) with normal nerve conduction studies, elevated CSF protein, enlarged and/or enhancing nerve roots on lumbar MRI, and delayed somatosensory evoked potentials.
3. Pure-motor CIDP: only motor nerve involvement with normal sensory nerves.
4. Multifocal Motor Neuropathy (MMN): It is only mentioned here because of somewhat similarities of symptoms, though it is a different type of illness, and discussed in a separate section.
5. Multifocal Acquired Demyelinating Sensory and Motor Neuropathy (MADSAM): It is similar to MMN that it is multifocal instead of diffuse, and different because it involves sensory nerves. It may affect nerves of upper extremity and/or cranial nerves. Diagnosis is made with same tools described above. This condition can respond to both IV-Ig and steroids.
6. Distal Acquired Demyelinating Symmetric Neuropathy (DAD): It mostly affects lower extremities with involvement of sensory and motor nerves, causing weakness and unsteadiness. Patients may have associated IgM monoclonal gammopathy, and MAG or sulfated glucoronyl paragloboside antibodies. EMG/NCS studies may reveal extremely prolonged sensory and motor distal latencies, and severe slowing of conduction velocities in lower extremities. Biopsy may reveal areas of demyelination with IgM and complement deposits. Patients with MAG antibodies are treated with rituximab. Patients without MAG antibody respond to treatment with steroid, IV-Ig, and plasma exchange.
7. Nodopathies and Paranodopathies: In these conditions, antibodies attack nodal (nod of Ranvier) or paranodal regions of nerves. These are diagnosed based upon immune testing of nerve biopsy. Antibodies acting in these conditions are IgG4 type. Treatment options are IV-Ig, steroids, plasma exchange, and rituximab.

 

Where can I find more information about CIDP?

American Academy of Neurology

GBS/CIDP Foundation International