Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune condition where the body’s immune system mistakenly attacks the protective covering of nerves, leading to muscle weakness and sensory changes that develop gradually over weeks to months. Though challenging, CIDP is treatable, and early diagnosis can make a significant difference in preventing long-term nerve damage.
Epidemiology
Chronic inflammatory demyelinating polyradiculoneuropathy is a rare neurological condition that affects a small portion of the population worldwide. Researchers estimate that there are approximately 0.8 to 8.9 new cases of CIDP per 100,000 people in the United States each year. This wide range exists because CIDP can affect people in many different ways, making it difficult to diagnose consistently.[1]
The estimated worldwide prevalence of CIDP is about 3 per 100,000 people, with the incidence being less than 1 per 100,000 per year.[10] However, because the disease can be present in a person for years before diagnosis, the overall prevalence reflecting the accumulation of cases over time may be as high as 9 per 100,000 in some areas.[7] In the United States, up to 29,000 people are thought to have CIDP.[3]
CIDP can affect anyone at any age, from children to the elderly. However, there are clear demographic patterns in how the condition manifests. Men are twice as likely as women to be affected by CIDP.[3] While CIDP may appear at any age, people usually develop symptoms at around 50 years old. The condition mainly impacts adults, though approximately 10% of CIDP cases occur in children.[3]
Causes
CIDP is caused by an abnormal immune response in which the body’s immune system mistakenly attacks the myelin sheath, which is the protective covering that wraps around nerve cells. This protective sleeve acts like insulation on electrical wires, allowing nerve signals to travel quickly and efficiently through the body.[1]
Healthcare providers consider CIDP to be an autoimmune disease, meaning the immune system, which normally protects the body from germs and illness, fails to recognize parts of the body’s own nerves and begins attacking them.[6] When this happens, excessive inflammation damages the peripheral nerves—the nerves outside of the brain and spinal cord that send messages between the body and the brain to control essential functions like moving muscles, maintaining a heartbeat, and digesting food.[3]
The specific triggers of CIDP vary considerably, and in many cases, the exact cause cannot be identified. However, CIDP may occur alongside other medical conditions. These include chronic hepatitis, diabetes, infection with the bacterium Campylobacter jejuni, HIV/AIDS, immune system disorders due to cancer, inflammatory bowel disease, systemic lupus erythematosus, cancer of the lymph system, and overactive thyroid. Additionally, CIDP can sometimes develop as a side effect of medicines used to treat cancer or HIV.[6]
Researchers think CIDP happens due to issues with the immune system, specifically a type of autoimmune attack that causes the destruction of myelin through a process called demyelination. This destruction interferes with the ability of nerves to transmit electrical signals properly, leading to the various symptoms associated with the condition.[1]
Risk Factors
While CIDP can affect anyone, certain groups of people and specific circumstances may increase the risk of developing this condition. Understanding these risk factors can help in early identification and prompt treatment of the disease.
Age is a notable risk factor, as symptoms typically develop around 50 years old, though the condition can occur at any age. Gender also plays a role, with men being twice as likely as women to develop CIDP.[3] This gender difference suggests that biological or hormonal factors may influence susceptibility to the condition.
People with certain underlying medical conditions face an elevated risk of developing CIDP. Those with diabetes, chronic hepatitis, or HIV/AIDS may be more susceptible to the condition. Individuals with autoimmune diseases such as systemic lupus erythematosus or inflammatory bowel disease also have an increased risk, as their immune systems are already predisposed to attacking the body’s own tissues.[6]
Infection with specific bacteria, particularly Campylobacter jejuni, has been associated with an increased risk of CIDP. Additionally, people with immune system disorders caused by cancer, such as lymph system cancers, may be at higher risk. Those taking certain medications, particularly medicines used to treat cancer or HIV, may also face an elevated risk of developing CIDP as a side effect of their treatment.[6]
Symptoms
The symptoms of CIDP can vary based on the specific type or variant of the condition, but the most common symptom is muscle weakness that gets worse over at least eight weeks. This progressive weakness typically affects muscles on both sides of the body equally, creating a symmetric pattern of impairment.[1]
Muscle weakness most commonly affects the hips and thighs, shoulders and upper arms, hands, and feet. This pattern of weakness can make everyday activities increasingly difficult. People with CIDP often report having trouble getting out of a chair, walking, climbing stairs, and experiencing falls. Problems with gripping objects, tying shoe laces, and using utensils can develop when the upper limbs become involved.[7]
Beyond muscle weakness, people with CIDP frequently experience abnormal sensations known as paresthesia. These include tingling, prickliness, or numbness in the fingers and toes. Some people describe feeling a “tingling” sensation similar to an electrified vibration in their arms and legs. Sensory involvement can lead to proprioception impairment (difficulty sensing where your body parts are in space), loss of feeling, and poor balance. Vibration and position sense are typically affected more than pain and temperature sense.[1][2]
Many people with CIDP experience difficulties with balance and coordination, often described as clumsiness. A particularly common problem is “foot drop,” an inability to lift the front part of the foot, which makes walking challenging and increases the risk of tripping.[3] Loss of mobility is common as the disease progresses, and many affected individuals may have trouble with daily tasks such as daily grooming, getting dressed, eating, carrying items, and opening bottles or turning keys.[3]
Additional symptoms include loss of muscle mass (atrophy) in affected muscles, loss or weakening of deep tendon reflexes, and fatigue. While less common, some people experience neuropathic pain, which can include burning pain in the arms and legs. Cramping in the feet or hands may also occur.[1][3]
In rare cases, CIDP can cause difficulty swallowing (dysphagia) and weakness above the neck, as well as double vision. These symptoms may change in severity over time and can come on slowly or rapidly. Sometimes symptoms come and go over time, following a pattern of improvement and relapse.[1]
The impact of CIDP extends beyond physical symptoms. Fatigue has been identified as common in CIDP patients, though it remains unclear how much this results from the disease itself or from the overall burden of being ill. In a study of nearly 500 CIDP patients, 20% missed school or work and 47% stopped working altogether due to their condition.[3]
Prevention
Because CIDP is an autoimmune condition with largely unknown specific triggers, there are no established methods to prevent the disease from developing in the first place. The exact reasons why some people develop CIDP while others do not remain unclear, making primary prevention challenging.
However, for people already diagnosed with CIDP, certain lifestyle measures may help prevent relapses and maintain overall health. A healthy lifestyle can help prevent other illnesses and infections that have been shown to trigger relapses of CIDP symptoms and can generally improve feelings of wellbeing.[13]
Maintaining good physical health through proper nutrition is important when living with CIDP. A nutritious and balanced diet helps ensure that the body receives all necessary vitamins and minerals. While there is no evidence of any special dietary requirements specifically for CIDP, it is sensible to manage weight to avoid putting excess strain on muscles, which might cause additional disability. There is no specific diet plan that exists for CIDP, but certain foods with anti-inflammatory properties may help reduce inflammation in the body.[13][17]
Physical exercise can play a key role in managing CIDP and potentially preventing symptom worsening. Regular exercise can help improve nerve and muscle strength. However, it is important to choose the right level of exercise and take rest periods between exercises to avoid fatigue or injury. Healthcare providers and physiotherapists can help build exercise plans that suit individual needs and abilities.[13]
Since infections have been shown to trigger CIDP relapses, taking steps to avoid infections through good hygiene practices, staying up to date with appropriate vaccinations (as recommended by healthcare providers), and avoiding exposure to sick individuals when possible may help reduce the risk of symptom flare-ups.[13]
Pathophysiology
To understand how CIDP affects the body, it is helpful to know how nerves normally function. The peripheral nervous system consists of nerves that extend throughout the body, connecting the brain and spinal cord to muscles, organs, and skin. These nerves are responsible for sending messages that control essential body functions and allow us to sense our environment and move our bodies.
Healthy nerves are wrapped in a protective covering called the myelin sheath, which acts much like the rubber insulation wrapped around electrical wires. This myelin insulation is made up of protein and fatty substances and allows electrical impulses to travel quickly and efficiently along the nerves. When myelin is intact, nerve signals can move rapidly from one part of the body to another, enabling coordinated movement and accurate sensory perception.[3][15]
In CIDP, the immune system mistakenly identifies the myelin sheath as foreign or dangerous and launches an attack against it. This autoimmune response causes inflammation of the nerve roots and peripheral nerves, characterized by a process called segmental demyelination. As the myelin is damaged or stripped away from the nerves, the ability of these nerves to transmit electrical signals becomes impaired.[2]
When the protective myelin layer is damaged or removed, the electrical messages sent to and from the brain are disrupted and may never reach their intended destination. This disruption in nerve signaling is what causes the symptoms of CIDP. For example, when the brain sends a signal to lift the foot while walking, but the damaged nerves cannot properly transmit this message, the result is foot drop or difficulty walking. Similarly, when sensory nerves are affected, the brain may not receive accurate information about touch, temperature, or the position of body parts in space.[3][15]
The inflammatory process in CIDP is chronic and progressive, meaning it is long-term and can worsen over time. The condition develops slowly over at least eight weeks, distinguishing it from related acute conditions. In some cases, the body attempts to repair the damaged myelin through a process called remyelination, but this repair is often incomplete or ineffective. The repeated cycles of demyelination and attempted remyelination contribute to the relapsing and remitting pattern that some people with CIDP experience.[1][2]
Over time, if left untreated, the ongoing inflammation and demyelination can cause permanent damage to the nerves themselves, not just the myelin covering. This can result in irreversible muscle weakness, loss of sensation, and disability. The progression of nerve damage explains why early diagnosis and treatment are so critical in preventing long-term complications of CIDP.[15]
CIDP is closely related to Guillain-Barré syndrome (GBS), and healthcare providers consider CIDP to be the long-term form of GBS. Both conditions involve autoimmune attacks on peripheral nerve myelin. The primary difference lies in the timeline of symptom progression. In GBS, the most severe stage usually occurs around two to three weeks after symptoms start, and most people begin improving after this point. In contrast, CIDP symptoms worsen over at least eight weeks and follow a more chronic course.[1]
