Osteomyelitis

Answer 1

Definition

Osteomyelitis is an acute or chronic bone infection.

Causes, incidence, and risk factors

Bone infection can be caused by bacteria (more common) or fungi (less common).

• Infection may spread to a bone from infected skin, muscles, or tendons next to the bone, as in osteomyelitis that occurs under a chronic skin ulcer (sore).
• The infection that causes osteomyelitis can also start in another part of the body and spread to the bone through the blood.
• A current or past injury may have made the affected bone more likely to develop the infection. A bone infection can also start after bone surgery, especially if the surgery is done after an injury or if metal rods or plates are placed in the bone.

In children, the long bones are usually affected. In adults, the feet, spine bones (vertebrae), and the hips (pelvis) are most commonly affected.

Risk factors are:

• Diabetes
• Hemodialysis
• Injected drug use
• Poor blood supply
• Recent trauma

People who have had their spleen removed are also at higher risk for osteomyelitis.

Symptoms

• Bone pain
• Fever
• General discomfort, uneasiness, or ill-feeling (malaise)
• Local swelling, redness, and warmth

Other symptoms that may occur with this disease:

• Chills
• Excessive sweating
• Low Back pain
• Swelling of the ankles, feet, and legs

Signs and tests

A physical examination shows bone tenderness and possibly swelling and redness.

Tests may include:

• Blood cultures
• Bone biopsy(which is then cultured)
• Bone scan
• Bone x-ray
• Complete blood count (CBC)
• C-reactive protein (CRP)
• Erythrocyte sedimentation rate (ESR)
• MRI of the bone
• Needle aspiration of the area around affected bones

Treatment

The goal of treatment is to get rid of the infection and reduce damage to the bone and surrounding tissues.

Antibiotics are given to destroy the bacteria causing the infection. You may receive more than one antibiotic at a time. Often, the antibiotics are given through an IV (intravenously, meaning through a vein) rather than by mouth. Antibiotics are taken for at least 4 - 6 weeks, sometimes longer.

Surgery may be needed to remove dead bone tissue if you have an infection that does not go away. If there are metal plates near the infection, they may need to be removed. The open space left by the removed bone tissue may be filled with bone graft or packing material that promotes the growth of new bone tissue.

Infection of an orthopedic prosthesis, such as an artificial joint, may need surgery to remove the prosthesis and infected tissue around the area. A new prosthesis may be implanted in the same operation. More often, doctors wait to implant the prosthesis until the infection has gone away.

If you have Diabetes, it will need to be well controlled. If there are problems with blood supply to the infected area, such as the foot, surgery to improve blood flow may be needed.

Expectations (prognosis)

With treatment, the outcome for acute osteomyelitis is usually good.

The outlook is worse for those with long-term (chronic) osteomyelitis, even with surgery. Amputation may be needed, especially in those with diabetes or poor blood circulation.

The outlook for those with an infection of an orthopedic prosthesis depends, in part, on:

• The patient's health
• The type of infection
• Whether the infected prosthesis can be safely removed

Complications

When the bone is infected, pus is produced in the bone, which may result in an abscess. The abscess steals the bone's blood supply. The lost blood supply can result in a complication called chronic osteomyelitis. This chronic infection can cause symptoms that come and go for years.

Other complications include:

• Need for amputation
• Reduced limb or joint function
• Spread of infection to surrounding tissues or the bloodstream

Calling your health care provider

Call your health care provider if:

• You develop symptoms of osteomyelitis
• You have osteomyelitis and the symptoms continue despite treatment

Prevention

Prompt and complete treatment of infections is helpful. People who are at high risk or who have a compromised immune system should see a health care provider promptly if they have signs of an infection anywhere in the body.

References

Espinoza LR. Infections of bursae, joints, and bones. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 293.

Gutierrez KM. Osteomyelitis. In: Long SS, ed. Principles and Practice of Pediatric Infectious Diseases. 3rd ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 80.

Answer 2

Definition

Osteomyelitis is an acute or chronic bone infection.

Causes, incidence, and risk factors

Bone infection can be caused by bacteria (more common) or fungi (less common).

• Infection may spread to a bone from infected skin, muscles, or tendons next to the bone, as in osteomyelitis that occurs under a chronic skin ulcer (sore).
• The infection that causes osteomyelitis can also start in another part of the body and spread to the bone through the blood.
• A current or past injury may have made the affected bone more likely to develop the infection. A bone infection can also start after bone surgery, especially if the surgery is done after an injury or if metal rods or plates are placed in the bone.

In children, the long bones are usually affected. In adults, the feet, spine bones (vertebrae), and the hips (pelvis) are most commonly affected.

Risk factors are:

• Diabetes
• Hemodialysis
• Injected drug use
• Poor blood supply
• Recent trauma

People who have had their spleen removed are also at higher risk for osteomyelitis.

Symptoms

• Bone pain
• Fever
• General discomfort, uneasiness, or ill-feeling (malaise)
• Local swelling, redness, and warmth

Other symptoms that may occur with this disease:

• Chills
• Excessive sweating
• Low back pain
• Swelling of the ankles, feet, and legs

Signs and tests

A physical examination shows bone tenderness and possibly swelling and redness.

Tests may include:

• Blood cultures
• Bone biopsy(which is then cultured)
• Bone scan
• Bone x-ray
• Complete blood count (CBC)
• C-reactive protein (CRP)
• Erythrocyte sedimentation rate (ESR)
• MRI of the bone
• Needle aspiration of the area around affected bones

Treatment

The goal of treatment is to get rid of the infection and reduce damage to the bone and surrounding tissues.

Antibiotics are given to destroy the bacteria causing the infection. You may receive more than one antibiotic at a time. Often, the antibiotics are given through an IV (intravenously, meaning through a vein) rather than by mouth. Antibiotics are taken for at least 4 - 6 weeks, sometimes longer.

Surgery may be needed to remove dead bone tissue if you have an infection that does not go away. If there are metal plates near the infection, they may need to be removed. The open space left by the removed bone tissue may be filled with bone graft or packing material that promotes the growth of new bone tissue.

Infection of an orthopedic prosthesis, such as an artificial joint, may need surgery to remove the prosthesis and infected tissue around the area. A new prosthesis may be implanted in the same operation. More often, doctors wait to implant the prosthesis until the infection has gone away.

If you have diabetes, it will need to be well controlled. If there are problems with blood supply to the infected area, such as the foot, surgery to improve blood flow may be needed.

Expectations (prognosis)

With treatment, the outcome for acute osteomyelitis is usually good.

The outlook is worse for those with long-term (chronic) osteomyelitis, even with surgery. Amputation may be needed, especially in those with diabetes or poor blood circulation.

The outlook for those with an infection of an orthopedic prosthesis depends, in part, on:

• The patient's health
• The type of infection
• Whether the infected prosthesis can be safely removed

Complications

When the bone is infected, pus is produced in the bone, which may result in an abscess. The abscess steals the bone's blood supply. The lost blood supply can result in a complication called chronic osteomyelitis. This chronic infection can cause symptoms that come and go for years.

Other complications include:

• Need for amputation
• Reduced limb or joint function
• Spread of infection to surrounding tissues or the bloodstream

Calling your health care provider

Call your health care provider if:

• You develop symptoms of osteomyelitis
• You have osteomyelitis and the symptoms continue despite treatment

Prevention

Prompt and complete treatment of infections is helpful. People who are at high risk or who have a compromised immune system should see a health care provider promptly if they have signs of an infection anywhere in the body.

References

Espinoza LR. Infections of bursae, joints, and bones. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 293.

Gutierrez KM. Osteomyelitis. In: Long SS, ed. Principles and Practice of Pediatric Infectious Diseases. 3rd ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 80.

Reviewed By

Review Date: 05/25/2010

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.