Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is an acquired immune-mediated inflammatory disorder of the peripheral nervous system but often can have central nervous system involvement. The disorder is sometimes called chronic relapsing polyneuropathy. 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.
The pathologic hallmark of the disease is loss of the myelin sheath (the fatty covering that protects nerve fibers) of the peripheral nerves.[edit]
Overview
Chronic inflammatory demyelinating polyneuropathy is believed to be due to immune cells, cells which normally protect the body from foreign infection, but here begin incorrectly attacking the nerves in the body instead. As a result, the affected nerves fail to respond, or respond only weakly, to stimuli causing numbing, tingling, pain, progressive muscle weakness, loss of deep tendon reflexes (areflexia), fatigue, and abnormal sensations. The likelihood of progression of the disease is high.
CIDP is 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 important in preventing irreversible axonal loss and improving functional recovery.[1]
Lack of awareness and treatment of CIDP is also due to limitations of clinical trials. Although there are stringent research criteria for selecting patients to clinical trials, there are no generally agreed-on 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 miss the diagnosis in a majority of patients, and patients are often left untreated despite progression of their disease.[2]
In some cases electrophysiological studies fail to show any evidence of demyelination. Though conventional electrophysiological diagnostic criteria are not met, the patient may still respond to immunomodulatory treatments. In such cases, presence of clinical characteristics suggestive of CIDP are critical, justifying full investigations, including sural nerve biopsy.[3]
[edit]Diagnosis
- Clinical neurological examination
Patients usually present with a history of weakness, numbness, tingling, pain and difficulty in walking. They may additionally present with fainting spells while standing up or burning pain in extremities. Some patients may have sudden onset of back pain or neck pain radiating down the extremities, usually diagnosed as radicular pain. These symptoms are usually progressive and may be intermittent.
On examination the patients may have weakness, and loss of deep tendon reflexes (rarely increased or normal). There may be atrophy (shrinkage) of muscles, fasciculations (twitching) and loss of sensation. Patients may have Multi-Focal Motor neuropathy, as they have no sensory loss.
The patient may present with a single cranial nerve or peripheral nerve dysfunction.
Autonomic system dysfunction can occur; in such a case, the patient would complain of orthostatic dizziness, problems with bowel and bladder functions, and cardiac problems.
Most experts consider the necessary duration of symptoms to be greater than 8 weeks for the diagnosis of CIDP to be made.
- Electrodiagnostics - electromyography (EMG) and nerve conduction study (NCS).
In usual CIDP, the nerve conduction studies show demyelination. These findings include:
- a reduction in nerve conduction velocities b;
- the presence of conduction block or abnormal temporal dispersion in at least one motor nerve;
- prolonged distal latencies in at least two nerves;
- absent F waves or prolonged minimum F wave latencies in at least two motor nerves. (In some case EMG/NCV can be normal).
- Serum test to exclude other autoimmune diseases.
- Spinal tap and serum test for Anti-ganglioside antibodies, which are one branch of the CIDP diseases, as anti-GM1 anti-GD1a anti-GQ1b.
Biopsy is considered for those patients in whom the diagnosis is not completely clear, when other causes of neuropathy (eg, hereditary, vasculitic) cannot be excluded, or when profound axonal involvement is observed on EMG.
