Erdheim-Chester Disease (ECD)
This condition occurs when histiocytes build up in different organs and tissues. Erdheim-Chester disease (ECD) can cause a wide range of symptoms. It is important that patients be diagnosed and treated early before this condition progresses, as it may lead to organ failure.
This condition most commonly affects the long bones of the arms and legs but it can also affect the tissues behind the eyeballs, kidney, skin, brain, lung, heart, pituitary gland, arteries, and a part of the posterior abdominal wall (called the retroperitoneum).
Symptoms vary widely depending on what body systems are affected and may include any of the following:
- Bone pain emanating from the legs and arms but also from the knees, shins, and ankles
- Less commonly, pain in the lower jaw, facial bones, and spinal column
- Joint pain
- Muscle pain
- Lower back pain, reduced kidney function/painful or difficult urination
- Abdominal or lower back pain, painful or difficult urination
- Rash or soft, fatty, yellow bumps on the skin or eyelids
- Difficulty with coordination, staggering gait
- Slurred speech
- Behavior disorders
- Rapid, involuntary eye movement
- Diabetes insipidus, a condition where the kidneys are unable to conserve water
- Dry cough, shortness of breath with exercise
- Pain and redness in the eyes, bulging eyes, difficulty with vision including double vision
- Excessive thirst and urination
- Shortness of breath, fatigue, and swelling of feet, ankles, and lower legs
Additional symptoms may include weight loss, fever, night sweats, weakness/fatigue, and increased tendency to get infections.
After blood tests and a physical exam, a tissue biopsy may be taken to distinguish this disease from Langerhans cell histiocytosis (LCH). After numbing the area, physicians insert a needle into the tissue to extract a sample of the patient’s cells. They then examine those cells under a microscope and test them for certain genetic changes.
On a cellular level, ECD differs in a number of ways from LCH. A pathologist can distinguish one disease from the other by looking at a stained tissue sample under a microscope.
Other diagnosis tests for this condition may include:
- Blood tests to evaluate function of the internal organs, such as heart and kidneys
- Neurological examination, testing the patient’s ability to walk and muscle coordination
- X-rays of the lungs or the bones to determine if there are abnormalities
- Bone scan, a type of X-ray that looks for bone lesions
- CT scan, an X-ray that takes a number of detailed pictures at different angles inside the body, after a contrast dye is injected into a vein
- MRI, another type of X-ray that takes a number of detailed pictures inside the body, using a contrast dye injected into the vein
- PET scan, using radioactive sugar injected into a vein. Diseased cells show up brighter on the scanner
- Ultrasound, using high-energy sound waves to form a picture of the internal organs
- Electrocardiogram, tracing the heart rate and rhythm
- Echocardiogram, using sounds waves to take pictures of the heart in order to evaluate blood flow and heart function
The severity of this disease depends upon whether it is contained within the bone or affects other internal organs.
This condition is most commonly diagnosed in middle age, with the average onset at 53 years. It affects men and women equally. The rate of occurrence is unknown, and it is often misdiagnosed. At present the cause of ECD is unknown, but some patients with LCH can develop ECD.
Because this is a very rare and recently identified disease, no large studies have been performed and no treatment plan has been widely accepted. However, various treatments have been effective with individual patients including:
- Immunotherapy, using injections of the drug interferon to boost the ability of the immune system to fight off infections
- Systemic corticosteroids, hormonal drugs reduce inflammation in the body
- Vemurafenib, a drug that targets the BRAF protein, works in patients who have a mutation in BRAF—about 50% of the patients with ECD
- Anakinra (Kinaret) is a drug that targets the interleukin 1 receptor and can suppress the immune system
Although these therapies may control the symptoms and growth of the disease, to date there is no known cure for ECD. With treatment, however, some patients are able to live a nearly normal life. Some patients with ECD do not require treatment and can be followed closely.