How Serious Is Bone Marrow Edema?

Bone marrow edema, also referred to as a bone marrow lesion, can be caused by a bone or tendon injury or by a more serious condition like arthritis, osteoporosis, bone infections, bone tumors, or cancer.

Bone marrow edema is characterized by the build-up of fluid in the spongy part of the bone, called the bone marrow. It may not cause any symptoms and only be spotted with an X-ray. Or, it may cause pain and swollen joints due to joint effusion. The treatment varies by the underlying cause.

This article describes common causes of bone marrow edema. It also explains how the condition is diagnosed and treated.

Causes

As with all forms of edema, bone marrow edema involves the swelling of tissues due to the build-up of fluids. There are many different causes for this.

Injury

Bone marrow edema can occur due to an injury of a bone or connective tissues like ligaments and tendons. The injury may be acute (sudden, severe) or chronic (persistent or recurrent). This includes overuse injuries caused by repetitive stress to bones and joints.

Injuries like this cause inflammation, a normal protective response that causes the widening of blood vessels and swelling of surrounding tissues.

Injuries that can cause bone marrow edema include:

• Stress fracture
• Bone bruises
• Tendinitis
• Joint dislocation
• Anterior cruciate ligament (ACL) tear
• Plantar fasciitis
• Achilles tendon rupture
• Complex regional pain syndrome

Arthritis

Both inflammatory and non-inflammatory arthritis can cause bone marrow lesions. With non-inflammatory arthritis, the degeneration of bone can cause changes that place direct pressure on the underlying marrow.

Types of arthritis that can cause bone marrow edema include:

• Osteoarthritis: A non-inflammatory "wear-and-tear" arthritis
• Rheumatoid arthritis: An inflammatory autoimmune arthritis
• Psoriatic arthritis: Another autoimmune form linked to psoriasis
• Reactive arthritis: Typically caused by medication reactions
• Gout: An autoimmune form also known as gouty arthritis
• Septic arthritis: Caused by a bacterial or fungal infection on or near a joint

Osteoporosis

Osteoporosis is a condition that causes bones to become porous and brittle. Osteoporosis is increasingly common as a person ages, particularly in postmenopausal women. The instability caused by osteoporosis makes bones vulnerable to fracture.

Bone marrow lesions are commonly found in people with severe osteoporosis, particularly in the knees and hips.

Osteomyelitis

Osteomyelitis is an infection of the bone. It is relatively uncommon but can cause damage to the blood vessels servicing the bone. If the blood supply is significantly reduced, bone tissues can start to die (referred to as osteonecrosis). Bone marrow edema is characteristic of osteomyelitis, especially in the hip.

Osteomyelitis is most commonly caused by bacteria, the chief of which include Staphylococcus aureus. Less commonly, fungal infections can invade bones and cause osteomyelitis.

Bone Tumors

Benign (non-cancerous) bone tumors can cause edema by placing direct stress on the bone marrow as they grow in size and invade tissues. Some bone tumors grow faster than others.

There are many different types of benign bone tumors, including:

• Chondroblastoma: A type found in children that cause significant pain
• Chondromyxoid fibroma: A rare type that starts in the bone marrow
• Enchondroma: A type situated inside the bone marrow space
• Giant cell tumor. A rare but aggressive type of bone tumor
• Non-ossifying fibroma: The most common bone tumor in children
• Osteoblastoma; A type that is more common in males
• Osteochondroma: A type that grows outside of the bone
  
• Osteoid osteoma: A type usually found in the long bones of the body
  
• Unicameral bone cyst: A type found near the ends of long bones

Cancer

Cancers associated with bone marrow edema not only include those that start in the bone or bone marrow but those that spread (metastasize) from other parts of the body to the bone or bone marrow.

These include:

• Osteosarcoma
• Chondrosarcoma
• Ewing sarcoma
• Multiple myeloma
• Leukemia
• Non-Hodgkin lymphoma

Almost all cancers can spread to the bone, but the cancers that most often do include breast cancer, lung cancer, prostate cancer, renal (kidney) cancer, melanoma, ovarian cancer, and thyroid cancer.

Diagnosis

A healthcare professional can usually diagnose bone marrow edema with a physical exam, blood tests, and ultimately imaging studies that can confirm the presence of lesions in the bone marrow.

Lab tests may include:

• Complete blood count (CBC): Useful in detecting infection or bone marrow dysfunction
• C-reactive protein (CRP): Used to detect generalized inflammation
• Erythrocyte sedimentation rate (ESR): Also used to detect generalized inflammation
  

Imaging tests commonly used to visualize bone and bone marrow include:

• X-ray: Useful in detecting bone or joint damage and fractures
• Computed tomography (CT): Provides more detailed information about bone tissue and structure
• Magnetic resonance imaging (MRI): Especially useful in visualizing soft tissues like bone marrow
• Bone scintigraphy (bone scan): Especially useful in detecting bone cancer
  

Treatment

The treatment of bone marrow edema varies by the underlying cause. Some types are harder to treat than others.

If the problem is related to an injury, rest and physical therapy may be all that is needed. Other cases require prolonged immobilization, cortisone injections to manage pain and inflammation, and surgery. The same may be needed for people with severe osteoarthritis.

Autoimmune forms of arthritis often require a class of medications known as disease-modifying anti-rheumatic infections (DMARDs).

Osteoporosis is commonly treated with exercise, vitamin and mineral supplements, and medications known as bisphosphonates.

Bone infections may require aggressive antibiotic or antifungal therapy delivered intravenously (into a vein), Bone tumors may be treated surgically if they cause pain, restrict movement, or pose a risk of a fracture.

Bone cancer may require chemotherapy, radiation, immunotherapy, and surgery.

Summary

Bone marrow edema is a buildup of fluid inside your bones. It can happen because of an injury such as a fracture. Or, it can be related to a health condition like osteoarthritis, a bone infection, or a bone tumor.

Your healthcare provider can usually diagnose bone marrow edema using an X-ray, CT scan, MRI scan, or bone scan. The treatment varies by the underlying cause.