Osteitis is an inflammation of bone tissue. It can be combined with inflammation of soft tissues, periosteum (periostitis) and bone marrow (myelitis). Osteitis can affect any bone in the body. Usually, this inflammation is infectious. The infection can be introduced into the bone from the external environment, during injuries and operations, with the blood flow from other organs, and also directly from nearby inflamed soft tissues.
What is this? General information
Osteitis is a general medical term meaning that the bone tissue is inflamed. It is sometimes used in dentistry, otolaryngology, but is almost never used in orthopedics.
Isolated osteitis is usually tuberculosis of the bones. In all other diseases, inflammation of bone tissue is combined with inflammation of the periosteum and bone marrow. Therefore, in orthopedics and surgery, inflammatory processes of the bone are called osteomyelitis, not osteitis.
Causes
Osteitis is a disease of microbial origin. Most often it is caused by bacteria, less often by fungi.
The causative agents of ostitis can be staphylococci, streptococci, enterobacteria, pseudomonas, E. coli, enterococci, bacteroids, mycobacteria, candida, actinomycetes, Pseudomonas aeruginosa and other flora – both pathogenic and opportunistic.
Pathogenesis
Osteitis develops as a result of infection getting into the bone. It can get there in different ways, but there are three main ones:
- trauma with the introduction of infection from the external environment (open fracture, foreign body in the bone, gunshot or shrapnel wound);
- purulent infection of adjacent soft tissues that gradually reaches the bone;
- disruption of the blood supply to bone tissue, which most often occurs in diabetes mellitus (diabetic foot);
- surgery or an invasive procedure, especially one involving the placement of an implant in the bone;
- infection spreading through the blood from other parts of the body, such as from the lungs in tuberculosis.
Osteitis can also develop as a complication after the administration of the BCG vaccine, both as part of vaccination against severe forms of tuberculosis and during treatment. For example, BCG is administered into the bladder to treat cancer of this organ.
Classification
Depending on the method by which microorganisms enter the bone, ostitis can be:
- endogenous – bacteria or other microbes that penetrate the bone are inside the body;
- exogenous – the causative agent of ostitis enters the bone from the external environment, usually as a result of trauma, less often as a result of surgery or a minimally invasive procedure, such as a bone biopsy.
Clinical forms:
- acute osteitis – without bone sequestration according to pathomorphological examination;
- chronic osteitis – with bone sequesters (islands of bone tissue death) that appear during a long-term inflammatory process.
Depending on the localization, ostitis can be of tubular and flat bones.
By pathogen:
- non-specific – caused by non-specific microbial flora;
- specific – caused by a specific pathogen (tuberculosis, syphilis).
Symptoms
Symptoms are mild. Many patients have no symptoms at all. If symptoms do appear, the main complaints are mild pain in the bones, which intensifies with movement, hot skin over the bone, swelling, and redness in this area. A slight increase in body temperature is possible. With vertebral ostitis, they become painful when pressed.
Complications
With ostitis, inflammation can spread:
- on adjacent tissues – soft tissue structures, joints;
- to distant organs and tissues – if pus gets into the blood, it can reach the lungs, kidneys, brain and other organs.
Osteitis can cause sepsis, thromboembolic complications, and also causes consequences for the musculoskeletal system: bone deformation, fractures. In severe cases, ostitis is treated by amputation of the limb, which leads to patient disability.
Diagnostics
The following methods are used to diagnose ostitis:
MRI. The most accurate non-invasive diagnostic method. Allows to detect signs of ostitis already 3 days after the onset of the disease with a sensitivity of up to 90%.
Osteoscintigraphy. An alternative to MRI if there are contraindications. A radioactive substance is introduced into the body, and then during scanning it is checked where it accumulates and in what quantity. The method has high sensitivity, allowing to detect changes in bones in the first days after the onset of the disease. But the specificity is lower than that of MRI. Therefore, osteoscintigraphy is mainly performed on patients who have metal implants in the body (contraindications for MRI).
Radiography. The most commonly used method. It is possible to detect foci of demineralization of inflamed bone tissue. The problem is that the changes become noticeable with the loss of more than 20% of bone substance, and become obvious with the loss of more than 50% of bone substance. Therefore, even experienced specialists can detect signs of ostitis on X-rays no earlier than 10 days after the onset of the disease.
Blood culture. Helps to identify infectious agents, but only in cases where bacteria enter the bone through the blood – hematogenously. This route of infection is more typical for children, but is rare in adults.
Bone biopsy. A mandatory method for confirming the diagnosis. In case of osteitis, doctors must take a tissue sample, examine it under a microscope, and also perform a culture on a nutrient medium to understand which bacteria caused the osteitis and which antibiotics are best to treat the disease. A bone biopsy is performed using an open or percutaneous (minimally invasive) method. An open biopsy is a more accurate method. This is a small operation to remove a fragment of bone tissue. A less accurate, but also less traumatic method is a percutaneous biopsy. This is the insertion of a thick needle, inside which a column of bone tissue remains. At least two samples are taken. The injection must be performed through non-inflamed skin. Otherwise, microorganisms that caused inflammation of the skin, not the bone, may grow on the nutrient medium.
Biopsy material culture. An important part of diagnostics, since osteitis can be caused by many pathogens. Based on the culture results, the bacteria that caused the inflammation are identified. Their sensitivity to antibacterial drugs is also assessed. These antibiograms allow choosing the optimal treatment regimen.
Treatment
Doctors carry out conservative and surgical treatment for ostitis.
Antibiotics are a mandatory element of treatment. They are administered intravenously. The drugs prescribed depend on the pathogen isolated from the bones. These may be penicillin, vancomycin, cefepime, clindamycin or other drugs. Sometimes two antibiotics are used at once if there is a suspicion that the pathogen may be resistant to some drugs.
Antibiotic therapy for ostitis continues for several weeks or even several months. In the first weeks, the drugs are administered intravenously, and then a transition to oral administration is possible.
Physiotherapy – helps improve the blood supply to the tissues in the bone area. During antibiotic therapy, this improves their penetration into the bone, thereby increasing the effectiveness of antibacterial treatment. During the recovery period, due to improved blood supply, bone tissue regenerates and becomes denser.
Surgery is not necessary for acute osteitis, but is almost always performed for chronic osteitis. The exception is inflammatory processes of the pelvic bones and vertebrae, if implants that caused osteitis are not installed in them. Surgical intervention involves the extraction of foreign bodies, if any (implants, endoprosthesis components, metal structures, etc.), removal of dead tissue and purulent foci. In the case of extensive bone defects, plastic surgery is performed with autologous bone, artificial materials, or osteosynthesis is used, depending on the clinical situation. Some patients will require immobilization and skeletal traction after surgery.
Forecast
Acute ostitis is usually curable. In 10% of cases, the disease becomes chronic.
The prognosis depends on the pathogen. The highest risk of relapse is observed when bone inflammation is caused by Pseudomonas aeruginosa.
Prevention
Preventive measures for the patient have not been developed.
Doctors reduce the risk of developing osteitis during bone surgery by using perioperative antibiotic prophylaxis. Antibiotics are administered intravenously shortly before surgery and then after surgery.