OS Sheet #6 By Muhammad Okdeh

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OS Sheet #6 By Muhammad Okdeh

Post by Sura on 17/3/2012, 11:47 pm

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Re: OS Sheet #6 By Muhammad Okdeh

Post by Shadi Jarrar on 12/4/2012, 12:40 am

Osteomyelitis
Our lecture today will be about Osteomyelitis which means “Infection of the bone”. This condition is usually rare in the oral cavity because the head and neck area have a very good blood supply!
• The pathogenesis of Osteomyelitis is not only due to infection although infection is present, but the lack of proper blood supply causes necrosis and eventually Osteomyelitis.

• According to this we suspect that the mandible is more susceptible to this disease than the maxilla due to the fact that mandible blood supply is not as high as maxilla’s, and that mandibular bone is thick compared to the maxillary thin bone.

• The infection usually starts in the Cancellous bone and then if it was able to breach the cortical bone it spreads out then it goes to the periosteum and if not treated properly it can reach the soft tissues.

• So the idea is that bacteria have to invade and reach the deep structures, and once that occurs an inflammation takes place. This inflammation create a compressing pressure in the cancellous bone that compromises the blood supply that is provided through vessels passing through small channels within the bone. This decreased blood supply (ischemia) to a certain area causes necrosis of that particular area and eventually we might end up with osteomyelitis. >> again we have to remember that this condition is rare and it occurs in patients with underlying diseases, like immunocomromised patients.



Clinical appearance:

• This is how it appears clinically. You can see that part of the bone is yellowish because it is necrotic and it’s blood supply is somewhat decreased, the soft tissues are open because the underlying bone is dead and the periosteum doesn’t usually cover diseased bone. This leads to fenestration and openings and the bone get exposed. And if you try to squeeze this part of bone, you will get no blood.

• Again, Osteomyelitis is not a common finding and it is a rare thing to see Osteomyelitis in patients. So once this disease is encountered in a patient he should be investigated very well for any underlying systemic condition and it has to be treated properly.



We said that the disease is more common in the mandible than in the maxilla due to the difference in the blood supply.

Predisposing factors:
1- Odontogenic infections: they are the most common cause of bacterial invasion and inflammation in the oral cavity.
* CARIES >> pulp necrosis that might lead to>>inflammation around the root apex >> reaches the cancellous bone >> then it goes to the cortical bone.
2- Fractures of the jaw: a fracture if the maxilla or the mandible provide the bacteria with a pathway to reach the oral cavity and to cause deep invasion to the underlying structures.
3- Any surgical intervention in susceptible patients, these interventions include traumatic extraction and implants. Susceptible patients are those with underlying systemic condition like;
- ALCOHOLICS.
- MALNOURISHED PATIENTS.
- DIABETIC PATIENTS “ESPECIALLY IF IT WAS UN CONTROLLED”.
- CANCER PATIENTS for different reasons the first is they receive chemotherapy which affects their health. The other one is that these patients are somehow depressed so they have poor diet that affects their immune system.
- PATIENTS ON STERIODS.
4- Any other patient with compromised immune system has the risk of developing Osteomyelitis.

Causative agents:
Usually bacteria that cause Osteomyelitis is the normal bacteria that is present in the oral cavity. We all that we have a wide range of bacteria in the normal flora of the mouth, and any one of these species could be involved in causing Osteomyelitis, like;
- Strep. Cocci
- G –ve rods bacterium like provetilla.


Now the question is do the bacteria that cause ostemyelitis in the jaw bones differ from bacteria that cause Osteomyelitis in other bones of the body?
- Well, I looked for the answer and that’s what I found that the bacteria that cause Osteomyelitis in the bones of the body are mainly staph. Aureus with an established role of strep. Cocci as another agent!
>> read on Wikipedia about this topic.

• Again, Osteomyelitis incidence in the jaws is significantly less than that in other parts of the body due to, as we said before, their copious blood supply!

Classification:
Classification of Osteomyelitis used to follow a difficult and sophisticated system, but now things are much easier.

• Old system: they used to classify Osteomyelitis into ::
1)
> acute forms of Osteomyelitis
>chronic forms of Osteomyelitis
OR..
2)
>Suppurative Osteomyelitis: produces pus.
>non-suppurative Osteomyelitis
OR..
3)
>Diffuse sclerosing Osteomyelitis
>Focal sclerosing Osteomyelitis
classification systems are available here: http://lambda.univ.rzeszow.pl/kb/cbct/publikacje/classification.pdf

• Current system: Osteomyelitis is now classified into 2 entities ::
>Bacterial Osteomyelitis.
>SAPHO syndrome.


Bacterial Osteomyelitis: it includes most of the classification of the old system because they all share the same histopathology in that the share the same scenario of bacterial invasion.

Clinical features of bacterial Osteomyelitis:
- pain: is a common finding, any infection can lead to this sign.
- parasthesia.
- Swelling: is a common finding
- erythema in the overlying skin.
- With little or no radiographic changes at the beginning.
- Systemic signs and symptoms like fever and malaise are also expected but they are present in other sorts of infection, as well.
>PARASTHESIA : is a very important feature, and once your patient complain of parasthesia his complain should be taken seriously. Parasthesia is usually a result of one of two causes, it’s either Osteomyelitis or Malignancy! So the presence of this particular feature is an alarming sign for one of two dangerous and serious conditions.

A CLINICAL SCENARIO>>
“three years ago I had a patient referred from a dentist, the patient had some sort of radiolucent lesion related to his lower wisdom, pain and parasthesia were related to the lesion. The patient went for his dentist who decided to take out the wisdom suspecting that the radiolucency is merely an infection or a small cystic lesion. After taking out the wisdom signs other the parasthesia improved, when he came to us we took the complain seriously because parasthesia is not a common finding in patients with simple infections. A biopsy was taken and the results came out confirming the presence of Osteomyelitis, so the patient was moved to the theatre and a part of the bone was removed and sent again to the lab as a routine procedure. And the results came up with a metastatic tumor that is most possibly coming from the lung. The patient was 45 yrs old; he was healthy, non-smoker, non-alcoholic, with no risk of malignancy! After the biopsy results suggested that the origin might be a primary pulmonary tumor, the patient was sent for CT scan which confirmed the diagnosis! So in our case a diagnosis of a primary tumor in the lung was made because the patient was complaining of parasthesia related to a lesion that metastasized from the lung to the jaw! ”. When we talk about parasthesia we are mainly talking about either infection of the bone “osteomyelitis” or malignancy. Keep in mind that this might be not always the case, for example patients with long standing infections or benign aggressive tumors or diabetes at certain stage of the disease might experience parasthesia as a result of permanent deformity in the nerve endings.

At the beginning, radiographs appear to be normal, but with time changes in the x-ray take place. These changes are described by the moth-eaten appearance of the bone. (as if it was bitten by small organisms!)
>> with time osteomyelitis clinically “can causes” in addition to parasthesia and pain, pus formation >> then pus discharge that comes out of the bone >> then it either gets to the oral cavity through a sinus tract, or it goes out superficially to the skin through skin fistula. The formation of pus inside bone weakens the bone and might lead to pathological fracture as well.
• Pathological fracture is fracture of the jaws due to the presence of any disease in the bone that weakens the bone and makes minor trauma or even normal functional movements a favorable cause of fracture.

- One of the major differences between slowly growing lesions and fast growing lesions is that in slowly growing benign lesions the borders are distinguished radiographically while those of fast growing lesions are barely seen! And the same applies here, in that as the infection is growing the borders are not clear radiographically OR we call them ill-defined.


This is how a patient with osteomyelitis appears clinically. Notice the swelling on the right side of her face.

CT scan in diagnosis:
CT scans can help us in the diagnosis. Look at the following CT scan of the mandible. If you look at the left side you can see a notable swelling inside the cancellous bone compared to the other side. Expansion and thickening of the cortical bone is noticed as well as some soft tissue reaction. These sign can be seen on CT scan.
CT scan is not ordered as a routine. It is only ordered when the case needs it, like when the lesion is big and we are suspecting to have a pathological fracture.

TREATMENT:
How can we treat osteomyelitis?
- First of all we need to diagnose the case, which depends mainly on signs and symptoms and history taking.
- Diagnosis as we said can be built on many bases, like the present symptoms or the use of CT scans or sometimes we might depend on bone isotope scan . Active areas appear to be more pronounced due to the increased absorption of this particular site to the radioactive material.
- Then we have to look for any underlying conditions in the patient. So some tests could be run in order to get the complete image of what is the patient having. These tests include, CBC, electrolytes, renal function, liver function, sugar levels are also monitored. Here it worth to mention that it’s not a must to have an underlying conditions, but it’s your responsibility to look for any condition that the patient is not aware of.

Conservative treatment modalities:
 Usually in the early stages of osteomyelitis we start with antibiotics, we give him antibiotics for a long continuous period of time that’s not less than 4-6 weeks.
 Antibiotics given include:
- amoxicillin with clavulanic acid or clindamycin because they both are well absorbed in the bone and they act on the bone specially in the oral cavity. Another reason is that they act will against the bacteria that causes osteomyelitis.
 The patient has to stay on antiseptic oral mouth washes to keep the oral cavity clean and sterile as possible.

 Dressings can also be used; by applying certain medications on exposed areas to promote wound healing.
 The steps mentioned above are our first line of treatment.
There are other lines of treatment depending on the severity of the case. We also have to treat any present cause, like if the osteomyelitis was elated to an area with dento-alveolar abscess with a problematic tooth we have to treat the cause either by RCT or extraction of the tooth. Sometimes foreign bodies present after the fixation of a fracture should be removed in order for the infection to heal. Sometimes before we go the surgical solution or even during surgery we might use hyperbaric oxygen . The idea behind this is to increase oxygen concentration in the tissues once that happen the healing process becomes faster.

Surgical treatment modalities:
 Sometimes surgical intervention is inevitable.
 The idea of surgery depends on the presence of sequestra which is a dead piece of bone. Because it’s dead, it doesn’t respond to any type of previously mentioned treatment modalities. So one have to remove them all by a process known as sequestrectomy, the aim of this removal is to allow the blood supply to reach the area covered by this piece of bone in order for proper healing to take place. (Sometimes what happen is that the body pushes this piece out as if it was a foreign body, so the patient take it out by his own hands).
 Another modality is called decortication. We know that osteomyelitis starts in the cancellous bone and the problem is that enough blood supply cannot reach this area as needed because of the presence of thick cortical bone. (blood supply to the bone comes usually from the periosteum – from the outside to the inside of the bone). So what we do is to reflect a flap and then remove part of the cortical bone or drill a hole in it in order for blood to have an access to the inner side of the bone. This can also help in creating an escape pathway for pus, if present.
 In some cases where the condition is very severe and the bone is nearly destroyed in certain areas the only available solution is to resect the involved part of bone. Resection means removal of the infected bone and then a reconstruction surgery follows.

- Debridement is another conservative modality that involves the cleaning of the surface of infected bone by applying topical antiseptic agents and corticosteroids with some antibiotics.


>> Garre’s osteomyelitis is part of the old classification system of osteomyelitis, now it’s not there in the new classification, but it’s still considered as a clinical situation.
In garre’s osteomyelitis we are referring to the osteomyelitis which has the same histopathology of ordinary osteomyelitis. It’s due to bacterial infection, but it occurs in young patients. It usually start at an early age (6-7 yrs of age), and it’s very chronic so the patient will have episodes of osteomyelitis usually in the mandible with prominent swelling in the bone and onion-peel appearance.

Why does it appear like that? What happens actually is that the body tries to defend against the disease which is slowly growing. This gives the body to form layers of thick cortical bone surrounding areas of infections.

The disease usually continues till the age of 20, and then it subsides. What we need to do with cases of Garre’s osteomyelitis is to give antibiotics. And we have to know that although the disease is chronic, it’s not aggressive.

Many patients with this disease end up with losing most of their teeth, because they come to the dentist complaining of a very severe type of pain which is improperly diagnosed as being related to a tooth or more, and the suggested treatment would be extraction of the offending tooth. After the extraction things might become better, but this doesn’t last. They will have that form of pain again and again they will extract another tooth. And we have a similar case here in JUH for a girl who have half of her teeth extracted and she is still 20!!

Q: why the pain faded away after the extraction?
A: they say that the extraction create an opening inside the bone, which releases the pressure inside the cancellous bone and thus the signs and symptoms of the disease.

Q: how would the extraction socket heal, won’t osteomyelitis compromise the process?
A: actually this is one of the complications of ordinary osteomyelitis, but not garre’s osteomyelitis, because it is not related to the teeth and it usually occurs in deep areas of cancellous bone and – as we said- it is not very aggressive.

BISPHOSPHONATES:
Bisphosphonates usually affect bone metabolism and osteoblasts. They find that people on oral or I.V. Bisphosphonates are more prone to osteomyelitis. The idea here is that dentists have to be very careful in extracting teeth for patients who are on bisphosphonate therapy, and you have to avoid it when possible. So if the tooth can be treated simply by endo treatment, then go for it or if the patient has an asymptomatic remaining root, leave it in the socket. In case the extraction was inevitable, your procedure should be as atraumatic as possible and reflecting flaps should be avoided. Why? Because once you reflect a flap it means that you have reflected the periosteum as well, and as a result decreased the blood supply to that area.

SAPHO SYNDROME:
In order for the dentist to diagnose this syndrome he should have the following:
• Chronic recurrent multifocal osteomyelitis.
more than one area that appear to be affected by osteomyelitis, this area could be anywhere in the skeleton.
• Acute, subacute or chronic arthritis.
• Palmoplanter pustulosis.









K
• Skin lesions and acne!

So the disease is a combination between osteomyelitis, arthritis and skin lesions.
Bone isotopes scan is very helpful in diagnosing this syndrome by looking at the active sites and comparing active site with other normal sites. Active sites appear to have more dye concentration. Again try to compare the left side of the mandible with the right side in order for you have to a clear decision.

“THE END”
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Shadi Jarrar
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تاريخ التسجيل : 2009-08-28
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