CIDP: how nerve damage leads to symptoms

The nervous system is the body’s communication system, and it includes the brain, spinal cord, and peripheral nerves. The nervous system is sometimes compared to the electrical wiring in a building—and the nervous system works in part by generating small electric signals that travel along nerves.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a neurological disorder that causes damage to the nervous system.

How does CIDP damage the nervous system?

CIDP damages the nervous system by damaging myelin sheaths, layers of proteins and fatty substances that cover and protect nerves throughout the body. Myelin sheaths also help conduct the electric signals that travel along nerves. If the myelin sheath is damaged, this signaling will not work as well. As a result, signals can slow down or become blocked, and communication will break down between different parts of the body.

The exact causes of CIDP are not fully understood. There is evidence that the condition is an autoimmune disorder, a disease where the body’s immune system attacks and damages healthy tissues. Some types of CIDP are associated with autoantibodies, immune proteins that attach to healthy tissues and direct the immune system to attack.

Some cases of CIDP are associated with other health conditions, including hepatitis B and C infections, HIV, an autoimmune disease called systemic lupus erythematosus, and certain cancers.

What nerves does CIDP affect?

CIDP affects the nerve roots and the peripheral nerves. The nerve roots are the nerves that branch off from the spinal cord. The peripheral nerves are the nerves outside of the brain and spinal cord—such as the nerves that run through the limbs and the digestive tract.

What are the symptoms of CIDP?

As CIDP damages the myelin that covers nerve roots and peripheral nerves, it disrupts how nerve signals travel to different parts of the body. This can cause a number of symptoms and problems:

• CIDP can cause muscle weakness that affects balance, coordination, and fine motor skills. These changes can affect normal day-to-day activities, including walking. CIDP can also cause a loss of muscle mass and muscle tone.
• A person with CIDP may experience sensory symptoms, such as numbness, tingling, or other sensations, often in the arms and legs.
• A person with CIDP may also experience a loss of sensation—such as not being able to feel a pinprick on the arms and legs.
• CIDP can also affect the nerves that regulate involuntary functions, and cause complications that affect breathing, swallowing, digestion, bladder control, and heart function.

The symptoms and severity of symptoms caused by CIDP can vary from person to person.

Most people with CIDP experience what is called “typical CIDP.” With typical CIDP, muscle weakness and sensory symptoms occur symmetrically (on both sides of the body). Typical CIDP usually affects the muscles of the hips, shoulders, hands, and feet.

Other types of CIDP cause muscle weakness without sensory symptoms, sensory symptoms without muscle weakness, or symptoms that follow an asymmetric pattern (meaning that symptoms affect different parts of the body on different sides of the body). These types are less common, and are referred to as variants of CIDP or “atypical variants.”

CIDP can also be progressive or relapsing. With progressive CIDP, symptoms will steadily get worse over time. With relapsing CIDP, symptoms will start and stop.

Your best source of information

If you or a loved one is living with CIDP, your best source of information will be a healthcare provider. CIDP should be diagnosed and treated by a neurologist that specializes in neuromuscular disorders. There is no known cure for CIDP, but there are therapies that can help relieve symptoms and control the disease.