Acute and chronic osteomyelitis

Osteomyelitis involves the production of inflammatory material within the bone itself, pus and, if not controlled, the destruction of the bone itself and the passage of the infection to the soft tissues that surround it or to the exterior through fissures and channels.

How is it produced?

Osteomyelitis or bone infection is produced by the arrival of the microorganism to the bone by contiguity or by hematogenous route:

• Hematogenous osteomyelitis, is produced with the arrival of the microorganism through the blood that nourishes the bone. It assumes the 20% of osteomyelitis and usually acute osteomyelitis. Acute hematogenous osteomyelitis mainly affects children and older adults. In children, a single bone is usually affected, which is usually a long bone, especially the tibia, femur, or humerus. In most cases the primary focus of infection is unknown. In adults, one vertebra of the spine is usually affected. The primary focus of infection may be a urinary tract infection, dental infection, or contaminated catheters, although the origin is unknown in 50% of cases.
• Contiguous osteomyelitis It occurs because the microorganism reaches the bone when it is already infecting neighboring tissues, through penetrating wounds or open fractures, or as a complication of surgery (placement of a prosthesis or placement of screws, for example). They are usually diagnosed after several weeks or months, that is, when they are already chronic infections. They are the most frequent osteomyelitis and represent the 80% of all osteomyelitis.

Symptoms

The hematogenous osteomyelitis sharp of the kids It is a serious disease, it is usually accompanied by a great affectation of the general state, high fever and pain and tenderness in the affected bone. Mobility in the area may also be limited. Acute hematogenous osteomyelitis of the adult with vertebral involvement, it usually gives back pain and there is no serious affectation of the general state.

In the contiguous osteomyelitis symptoms are more nonspecific: pain in the affected area, external suppuration because the infection leaves the bone and travels to the skin, infection of surgical wounds, bed sores that penetrate to the bone, prostheses that begin to hurt, etc. Fever is not frequent.

Diagnosis

Given the clinical suspicion of osteomyelitis, the diagnosis is made by radiology, blood tests and especially bone cultures or suppuration if it exists. blood tests are nonspecific, but in chronic osteomyelitis two parameters are followed - C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) - which indicate active infection when elevated.

In x-rays changes suggestive of infection appear in the structure of the bone; Over time and if the infection is not controlled, signs of bone destruction appear. Radiological alterations do not appear until after a minimum of 10 days and vary according to the time of evolution of the infection: it goes from almost imperceptible lesions to the total destruction of the bone. The Technetium bone scan It is another option because it is very sensitive to diagnose osteomyelitis in its early but less specific stages, especially in chronic cases with bone destruction. In these cases, a marked leukocyte scan may be helpful. MRI or computed tomography also help determine the degree of bone involvement.

The most important thing in front of osteomyelitis is obtain a sample of the infected pus or bone to cultivate and determine the bacteria causing the infection before starting treatment. Punctures of the affected bone or joint must be carried out (by means of fine needle aspiration puncture), the pus must be cultured if it comes out due to suppuration from the surgical wounds, and, in acute cases, the blood must always be cultured. Sometimes you have to perform a bone biopsy (a procedure that is performed in the operating room). The culture determines the microorganism causing the infection and the antibiotic treatment can be adjusted.

Treatment

Treatment of osteomyelitis is based on the antibiotics and surgical treatment. The antibiotic kills the bacteria that cause the infection. Surgical treatment is necessary to clean infected bone or remove dead bone. Regarding antibiotic treatment, in this type of infection, treatment with high doses of antibiotics is necessary, as it can be very difficult for it to reach the infected bone well. For this reason initially are usually administered intravenously, so it may require hospital admission. Long-term treatment, lasting several weeks or even months in some cases, is also characteristic of this type of infection.

• In the Acute hematogenous osteomyelitis of children antibiotic treatment for 4 to 6 weeks is usually sufficient.
• In the vertebral osteomyelitis In adults, 6 to 8 weeks of antibiotics are usually needed. Rest is always recommended until back pain subsides. Surgical treatment is usually not necessary if there are no complications.
• In the contiguous osteomyelitis 4 to 6 weeks of antibiotics are usually required and then supplemented with surgical treatment to debride the underlying soft tissue infection or secondary bone injury.
• In the cases of chronic osteomyelitis Treatment involves prolonged courses of antibiotics and surgery to debride infected bone or remove necrotic or dead bone. Several surgeries may be necessary. Sometimes it is inevitable to end up amputating the part of the limb with infected bone, as in the osteomyelitis of the small bones of the feet of diabetics. It is very important in chronic osteomyelitis that the person maintains a good nutritional state to facilitate the healing of soft tissues and bones.

In the cases of infected prostheses, they usually have to change the prosthesis once the infection is controlled.

Precautionary measures

It is very difficult to prevent bone infections, you have to think about them before they occur and this is the task of healthcare personnel. In hematogenous osteomyelitis whose origin is another infection (dental, urinary), the logical thing is to think about treating the primary infection as soon as possible. For minimize risk osteomyelitis due to the contiguity of infected soft tissue, it is necessary to extreme hygiene measures to heal ulcers or diabetic foot lesions. In open fractures or penetrating wounds, antibiotics are usually given to prevent infection, although it is not always possible to avoid it. To prevent osteomyelitis secondary to surgical interventions, it is necessary to maximize the aseptic measures of the intervention, shorten the times of surgery, etc.

A type of osteomyelitis not very frequent but not unusual in our environment is the tuberculous osteomyelitis, the so-called pott's evil. It is a form of hematogenously spreading osteomyelitis in adults and usually affects one vertebra of the spine. It is treated with the usual antibiotics for tuberculosis, for several months.