Diagnosing Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
What is chronic inflammatory demyelinating polyneuropathy?
Chronic inflammatory demyelinating polyneuropathy (CIDP) is a medical condition involving inflammation of the peripheral nerves (the nerves located outside the brain and spinal cord). The term “demyelinating” denotes damage to the myelin sheath, which is the fatty, protective covering that surrounds nerve fibers. This damage is thought to be caused by an abnormal immune response, so CIDP is considered an autoimmune disease. The term “polyneuropathy” signifies that many nerves in the body are affected.
Chronic inflammatory demyelinating polyneuropathy is also known as the chronic form of Guillain-Barré syndrome, which is an acute inflammatory disease of the peripheral nerves. Symptoms must be present for at least eight weeks in order for a CIDP diagnosis to be considered.
How is chronic inflammatory demyelinating polyneuropathy diagnosed?
A diagnosis of chronic inflammatory demyelinating polyneuropathy begins with a physical examination and medical history. A physician may check muscle strength, balance, reflexes, and the ability to feel sensations in the hands, feet, arms or legs.
While there is not a specific test to diagnose CIDP, tests may be ordered to evaluate nerve function and to eliminate the possibility of other medical conditions.
- Electromyography (EMG) — Tiny electrodes are inserted into a muscle to record the electrical activity in the muscle. This test shows the health of the nerves that control the muscles.
- Nerve conduction test — Electrode stickers applied to the skin measure how fast electrical signals move through a nerve. A nerve conduction test is typically conducted as part of an EMG.
- Blood test — Certain blood tests can show proteins that may cause the immune system to attack the nerves. Blood tests may also be ordered to eliminate the possibility of other medical conditions.
- Nerve biopsy — A small piece of nerve is removed for analysis. The examination may show damage to the myelin sheath or damage to the nerve itself.
- Spinal tap — During a lumbar puncture, a small amount of fluid is removed from the spine for analysis. A high white blood cell count may indicate an infection instead of CIDP. A normal white blood cell count and high protein level may suggest CIDP.
In some cases, doctors may recommend treatment for chronic inflammatory demyelinating polyneuropathy even if unsure about the diagnosis. If symptoms improve with treatment, a diagnosis of CIDP is usually indicated.