Osteomyelitis: Symptoms, Treatment, Causes, and Diagnosis

We all have heard about the inflammation of different body parts and organs, similarly when there is inflammation of the bone ( including all the parts of the bone that are – periosteum, cortical, cancellous and the bone...

Fatal Infection of Bone

We all have heard about the inflammation of different body parts and organs, similarly when there is inflammation of the bone ( including all the parts of the bone that are – periosteum, cortical, cancellous and the bone marrow) it is known as osteomyelitis. However, we can say that it is an inflammatory condition of the bone that begins from within the bone (medulla) to the outer surface of the bone ( periosteum).

The cause of this inflammation is caused by various microorganisms which leads to the infection, so it is virtual synonymous with the infection of the bone.

Any part of the bone may be involved in this disease but in children, it commonly affects the long bones whereas, in adults, the vertebral column is most affected.

What is Osteomyelitis?

Osteomyelitis was first considered as deadly disease , because of its long therapies and the results were not even satisfying. But these days the incidence of osteomyelitis is because of the worldwide availability of newer antimicrobials and better awareness.

However, we still confront some cases of osteomyelitis because of:

• Certain resistance strains of the organisms
• Presence of immunocompromised people and medically handicapped individuals.

How does this infection occur?

Mostly bacteria are the reason for bone infection. Common bacteria that are involved are - staphylococcus.

Other aerobic bacteria involved are streptococcal ( beta-hemolytic streptococci,

Streptococcus viridans)

Sometimes  these bacterias such as klebsiella,  Proteus  M. Tuberculosis, T. pallidum, and actinomyces species may also be found in the lesion .

Hence,  osteomyelitis is not caused by any single bacteria but by a combination of various bacteria including aerobic and non-aerobic. Therefore it is known as polymicrobial disease.

How do bacteria enter and spread?

Bacteria enter through -

• Any infection -  any infection in the body allows bacteria and other microorganisms are able to produce  bacterial toxins and body immunity fails to stop them. This may also  interfere with the blood supply of the bone.
• Trauma -  This is the second leading to the cause. During trauma, the area gets infected with a number of microorganisms which en the body and spread throughout.

Bacteria spread through 

• By circulating through blood ( hematogenous spread)
• Directly by the wound ( trauma site)
• Vascular insufficiency,  is when the bone is unable to get an adequate amount of blood supply due to any systemic disease

Factors that are considered responsible for this disease :

• The predisposing factors for bone infection are
• Conditions that alter host defences-   This includes the systemic disease of the patient such as – diabetes mellitus, anaemia, malnutrition, drug abuse, chronic alcoholism, typhoid or tuberculosis. All these problems favour the osteomyelitis
• Vascularity of the bone -  If the person is having any kind of bone disturbance such as Paget's disease, osteoporosis, radiation therapy or any peripheral vascular disease it favours the occurrence of bone infection.
• Virulence of organisms-  It depends on the destructive nature of the bacteria and the host immunity. If the bacteria is able to destroy the host’s immune cells it may lead to infection of b.

How it is caused ?

Bacteria enters the blood and it is spread through blood( hematogenous route ). As bacteria enters it cause acute inflammation. As the bone marrow is the inner most part of the bone and bone contains all the blood vessels only in the bone marrow, inflammation starts from the inner portion of the bone.

Inflammation may or may not include the pus formation. This leads to an increase in pressure in the medullary portion ( inside the bone ) because of which the blood vessels collapse.

Hence there is no blood supply remaining to the bone.

Slowly this inflammation starts spreading from inner portion of the bone to the outer portion of the bone ( from medulla to cortical and cancellous bone to periosteum – outermost covering of the bone ) .

Therefore when bone remains with no blood supply it accumulates more pus and the bone ruptures and there becomes an opening  for the pus from inside of the bone. This opening is known as fistula.

This fistula can open through the skin or oral cavity.

Types of osteomyelitis:

It can be:

• Acute
• Subacute
• Chronic

On basis of pus formation:

• Suppurative ( pus-forming )
• Non suppurative (non-pus forming)

When the acute osteomyelitis is present in the body and it does heal for long time it gets converted into chronic osteomyelitis. . It means the disease is same disease just at different stages or periods..

On the basis if site :

Stage 1 – medullary osteomyelitis, It involves the medullary bone without cortical involvement.

Stage 2  -  superficial osteomyelitis, when bone defect is small that 2cm and it does not involve cancellous bone

Stage 3 – localised osteomyelitis, less than 2 I’m bone defect seen on radiograph, defect doesn’t involve the votes of either side

Stage 4 – diffuse osteomyelitis, the defect is less small that is less than 2 I’m but it can cause any kind of pathological feature and other infection

Acute osteomyelitis

It may appear to be a simple infection.

Causes

• Trauma
• Osteomyelitis because of systemic disease such as –AIDS, syphilis, malnutrition, alcoholism, drugs, herpes etc.

Clinical Features

• High fever, nausea, vomiting, anorexia, intense pain.
• Felling of panaesthesia ( tickling sensations ) or anaesthesia ( reversible loss of sensations)
• If it is involving jaws, it may also cause cellulitis or indicated swelling of moderate size
• Established cases are characteristic by -

Deep pain, malaria, fever, dehydration, anorexia.

Laboratory test or diagnostic test 

The complete blood count will present with 

• Moderate leukocytosis

Slightly elevated erythrocyte (RBC) sedimentation

• Anaemia

Albuminuria.

Treatment planning:

Best way to treat osteomyelitis is to remove the cause and fermentation with antibiotic cover.

Recommended antibiotic regimen-

• First choice – Penicillin therapy ( Penicillin V )and metronidazole or clindamycin. Definitive antimicrobial therapy is started after the blood culture and sensitive results.
• Regimen 2 – In this we take the required test (blood or plasma) culture the bacteria and then start the antibiotics for that specific bacteria.

Penicillinase-resistant penicillin , such as oxacillin can be used against the penicillinase resistance bacteria and ,  another  choice - is clindamycin. It is effective against penicillin are producing staphylococci, streptococci and anaerobic bacteria including bacteroids.

Chronic osteomyelitis:

Chronic osteomyelitis are  usually of two types

• Primary – which results from the less virulent bacteria which persist for long time.
• Secondary – when acute osteomyelitis is unable to heal properly and it is persistent for very long period..

Clinical features -

• Pain as well as tenderness usually occurs.
• Non-healing bony and overlying soft tissue wounds within the duration of soft tissue.
• Fistula formation
• Thickened or wooden character bone
• Due to osteomyelitis some pathological fracture may occur at that site.
• Abscess may be present in that area when can be infected or sterilised.

Radiographic examination

• Conventional radiography 

 Radiographic changes occur only 3 weeks after initiation of osteomyelitis process. The degree of bone alteration requires 4-8 days, after the onset of acute osteomyelitis .

• In early stage – the marrow spaces that are usually involved first get enlarged, after that it gets distributed to the canal system of the bone .
• In later stages – the outer surfaces of the bone start getting involved from inside to outside(medulla to the cortex of the bone ).

The gradual resorption around the periphery of the infected area of the bone separates it off as sequestrum. That means the infected part of the bone that is deprived of the blood supply is known as sequestrum.

Gradually the new bone can form over the infected bone, appear as onion skin, parallel to the cortex, this newly formed bone is known as the involucrum. The deposition of the involucrum that is  new bone is common in young children

Specialised radiographic techniques involves-

• Computer tomography(CT)
• Radioisotope scanning
• Positron emission tomography (PET).

Computer tomography –It can provide us about all the calcified as well as detrimental surface of the bone .. It helps in assessing cortical and trabecular integrity, the amount of lesion present, the opening present and various other aspects. It can also help in detecting necrotic bone fragments.However, the CT scan is expensive.

Radioisotope scanning -  Radioisotope Tc-99m methylene diphosphonate bone scanning can identify the areas of involvement and has been previously used to identify margins and the extent of calcified tissue involvemen

MRI( Magnetic resonance imaging) – It is the most effective way of detecting osteomyelitis as it is able to identify any infection of bone within 3-5 days of disease onset. But the MRI scanning has the highest negative results.

Positron emission tomography

The change in the bone composition during osteomyelitis can be seen up to 3 to 4 days for onset of disease.. As a result it helps in early diagnosis of the disease and this enables the early treatment planning.

Complications:

Tumor conversion- if this disease remains persistent for longer period of time then there are greater chances of converting it into carcinomas(neoplasms) especially squamous cell carcinomas. .

Management:

Treatment includes – conservative treatment and then surgical treatment

Conservative treatment

It includes – complete bed rest, supportive therapy, dehydration,

Blood transfusion, control of pain, intravenous antimicrobial agents , postoperative care and special needs for specific needs.

Supportive therapy also involves the balance intake of all the nutrients along with multivitamins.

Antimicrobial therapy is same as indicated above in case of acute osteomyelitis.

Surgical management includes 

Incision and drainage of the most prominent site of the lesion. After the incision, all the abscess is drained out and another incision is made away from the lesion is made to place the irrigation tube.  Continuous irrigation of the wound is done along with then administration of systemic antibiotics for at least 2-3 months.

If still, the sequestrum ( necrotic bone ) is present in that area it is removed with the surgery and a bone graft is placed within that area.

Post-operative care includes-

• Continued use of antibiotics, analgesics ( pain killers) and irrigation and cleanliness of the affected area are done.
• Adequate hydration, complete bed rest, and removal of sequestrum.
• The wound is closed by placing a drainage pipe in that which should be regularly cleaned.

Prognosis

• If proper aggressive and comprehensive therapy is done the recovery of osteomyelitis is always good but in some cases where osteomyelitis is associated with some other local or systemic disease such as immunosuppressive disorders or vascular problems, the treatment get worsen than the disease.
• In such cases long-term conservative treatment is the best option than to perform a surgery along with regular lab monitoring tests.

Other types of osteomyelitis are 

• Infantile osteomyelitis
• Garre’s sclerosing osteomyelitis
• Chronic sclerosing osteomyelitis
• Actinomycotic osteomyelitis
• Tuberculosis osteomyelitis

Infantile osteomyelitis 

It is a rare type of disease that is seen in infants.

The main cause of factors may include – trauma, any kind of infection, contaminated nipples and hematogenous spread of the bacteria.

Clinical features present with the sever pain, high fever, pyrexia, anorexia, dehydration, and vomiting.

Lab diagnosis usually shows the raised level of endocytosis.

Treatment options include 

Antibiotics through the IV route ( usually penicillins and penicillinase resistant penicillinase such as flucloxacillin)

Culture and sensitivity test are done for the determination of specific bacteria and then antibiotic regimen in given against that bacteria.

Surgery can also be performed in extreme cases.

Garre’s sclerosing osteomyelitis

It is also known as chronic non-supportive sclerosing osteomyelitis and chronic osteomyelitis with proliferative periostitis.

 In this specific case the infection remains only in the periosteum (the outermost part of the bone)

Or beneath the cortex and spreads into the interior portion of the bone ( medulla)

In this case it causes the thinking of the bone that can be easily visible on the radiograph.

Clinical features presents with the – localised hard swelling, non-tender bone, lymphadenopathy( swelling of the involved lymph nodes) and endocytosis is not found.

Radio graphically it presents with – calcified bone formation that is smooth can be easily observed. But the bone overgrowth is typically present beneath the periosteum ( outer surface of the bone)

Treatment options are – removal of the infection followed by the antibiotic regimen and the surgery can also be performed in requires cases.

Treatment without prevention is simply unsustainable