Osteomyelitis - Inflammation of the Bone
The terms osteomyelitis, periostitis and ostitis are frequently used as synonyms for inflammation of the bone.
Let’s have a quick look at the definition of the terms. Since the bone itself (the calcium structure) cannot get inflamed osteomyelitis (meaning bone marrow inflammation) and periostitis (meaning bone lining inflammation) would be the correct descriptions for an inflammation of the bone. Nevertheless ostitis is becoming more and more the term used.
The cause of an inflammation of the bone can come from outside – (exogenous factors) or from inside (endogenous factors). When both factors occur at the same time then we speak of combined forms. The so called idiopathic factors may also be regarded as a fourth form, consisting of bone inflammations of unidentifiable origin. Exogenous factors include, for example, numerous bacteria, viruses and fungi. They are potential pathogenic agents. If these pathogens find their way into our body they can cause an inflammation. If the inflammation gets into the bone then it’s a bone inflammation.
In the case of endogenous factors the cause lies in our own bodies. For example, in the case of diabetics the raised level of sugar of a diabetic leads to ever-increasing thickening of the walls of the blood vessels and thus an ever-poorer flow of blood.
The flow of blood can get so bad that certain areas of the body are no longer reached by it any more and the affected tissues die due to lack of oxygen and will be destroyed as a consequence of an inflammatory reaction - this can also occur in the bones, as shown in the animation and that would be an example of an endogenous osteomyelitis.
Idiopathic osteomyelitis means to the patient that, at the end of the day the doctor cannot find an adequate explanation for it.
In the area of the jaw the most common causes of bone inflammation are exogenous or, more accurately, iatrogenous (caused by the doctor). Thus often extractions and/or badly root-treated teeth lead to bone infections.
In the picture you can see an x-ray of an extraction wound (circled in blue), the bone in this area is inflamed (circled in red) – osteomyelitis. In order to diagnose osteomyelitis an x-ray is usually required. In the same picture you can see a tooth (circled in green), which has an inflammation of the bone going on at the tip of the root (circled in red), as can be seen from the dark spot.
An x-ray can provide a lot of information about the bone but if precision is needed then a CT or MRT scan is very useful. This brings us to the diagnosis of osteomyelitis - CT and MRT scans are very reliable diagnostic aids at a certain stage of the osteomyelitis but at a very early stage of the illness their usefulness is rather limited.
Nuclear medical examinations such as skeletal cintography (Tc-99m) are frequently being made use of in order to detect osteomyelitis. The radioactive element technetium will be seen to be concentrated in the areas with raised bone metabolism after being applied intravenously. This increased concentration can be seen from the outside by means of a special camera (the darker spots in the exposure). Unfortunately it is not possible with this method to distinguish between the different causes of the raised bone metabolism.
Is the cause an inflammation or only an innocent build-up of bone after all?
With the addition of special factors (marked anti-granulocyte antibodies for additional investigation) the examination can however be made more specific. Blood tests are likewise not specific and unfortunately the blood values of the inflammation do not always correlate with the values of the osteomyelitis - especially in the jaw area. A bone biopsy is usually the most reliable means of diagnosis, as this way the bone can be viewed very precisely under the microscope (histological examination), and it may be possible to isolate the offending pathogen on the culture glass (bacteriology). If this succeeds then an antibiogram can be carried out in order to find the antibiotic with which to destroy the pathogen.
However, biopsy has a couple of disadvantages. The examination is invasive (therefore a wound is unavoidable) and not all areas of bone can be biopsied easily. Sometimes the bacteriological investigations are not successful or it may happen that during the taking of the sample there is contamination of the sample, for example by non-specific bacteria from the mouth.
Finally, let us take a look at the treatment options for osteomyelitis. There are various treatment options available - in the worst case the affected bone must be removed but this is very seldom necessary. The most frequent and simplest treatment option is the prescription of antibiotics, which can be swallowed or applied intravenously. The latter gives a higher concentration of the active ingredient in the blood.
By means of oxygen therapy we enrich the concentration of oxygen in the blood, since within the inflamed bone there is frequently insufficient blood supply and consequently, too little oxygen, ideal conditions for the multiplication of bacteria which do not tolerate oxygen – anaerobic bacteria as they are known. Oxygen-rich blood should have an effect on them, as per the motto: a little blood but very rich.
Another very much talked about treatment is the removal of the sick bone and the filling of the resultant gap with replacement donor bone which has been enriched with an antibiotic. In the animation you can see how the donor bone with the antibiotic (shown in green here) is put in place. The inflamed bone (shown in red here) will be removed and the donor bone will be inserted in the resulting cavity. The antibiotic will then pass continually into the body over months and simultaneously the replacement bone can regenerate.
The advantage of this treatment is that far higher concentrations of medication can be placed specifically in the affected area unlike with the usual means of application (orally or intravenously). Examination over a long period of time is still needed in order to evaluate this treatment over several years.
Ideally you want to avoid it getting to that stage. At least the iatrogenic forms of osteomyelitis can be avoided through sterilisation and cleanliness in the dental clinic. You can see more about this in the videos "Sterility" and "Drape".
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