Bone Infection

Acute haematogenus osteomyelitis. Subacute haematogenous osteomyelitis. Chronic osteomyelitis.


Post-traumatic and post operative Osteomyelitis. Acute suppurative arthritis. Septic bursitis. Tuberculosis.

Duration

acute (less than 2 weeks), Subacute ( 2-6weeks) chronic (>6 weeks)

Inflammation of the bone and its content.

Acute pyogenic infections: are characterized by formation of pus (concentration of defunct leukocytes, dead and dying bacteria and tissue debris.). which is often localized in an abscess.

A O M : is almost invariably a disease of children.

When it is occurring in the adult there may be predisposing factor: low resistance due to debility disease (diabetes). Or drug(immunosupression ).

Causative organism

The causal organism is usually : Staphylococcus aureus.


streptococcus pyogenes ,strep.pnenmoniae.

In children > 4 years age: Haemophilus influenza, E.Coli, pseudomonas aeruginosa proteus miribilis and anaerobic bacteriods fragilis. salmonella in sickle cell infection.

Haemophilus influenza

E.Coli

Route of entry

Infection may reach the bones and joints via 1.The blood stream from the distant site (boil, tooth infection). 2.Or direct invasion from skin puncture.

Pathology

The most common site is the metaphysis of the long bone particularly around the knee joint.

There are peculiar arrangements of the blood vessels in that area :

the non –anastomosing terminal branches of the nutrient artery twist back in hairpin loops arrangements of capillaries slow down the rate of blood flow before entering the large network of sinusoidal veins

The relative vascular stasis favors bacterial colonization.

In infant there is still a free anastomosis between metaphyseal and epiphyseal blood vessel.

In adult haematogenous infection is more common in the vertebra than in long bones

The sequence of the pathological changes as follow. Inflammation. Suppuration during (2,3 days). Necrosis due to increasing (intraosseous pressure ).

vascular stasis . infective thrombosis. and periosteal stripping increasing compromise the blood supply, by the end of a week there is usually evidence of necrosis.


Pieces of bone may separate as SEQUESTRA which act as a foreign body causing Persistant discharge through a sinus until they removed.

Finally, it may through the skin to the surface and form a chronic sinus becoming a persistent sinus tract or cloacae. reactive new bone formation resolution, healing.

Location of infection

Children : primarily in the long bones (femur, tibia, fibula, humerus). Adults :(50-60s) - primarily vertebrae. Neonates : have multiple bone infectious sites

The onset is rapid and attacks in short time. The patient, usually a child or adolescent,. complains a severe pain in a limb, and the pain is not relieved by rest.

A complete history and physical examination are required to search for possible primary foci of infection. There may be some minor injury or insignificant infective lesion such as boil sore throat a few days earlier


The general symptoms of toxemia
①severe acute illness appear②irritable and restless③high fever, chill④rapid pulse, nausea, vomiting etc

local signs

calor, rubor, dolor, tumor. Heat, red, pain or tenderness, swelling. Initially, the lesion is within the medually cavity, there is no swelling, soft tissue is also normal.

The merely sign is deep tenderness. Localized finger-tip tenderness is felt over or around the metaphysis. it is necessary to palpate carefully all metaphyseal areas to determine local tenderness. pseudo paralysis .

Subperiosteal abscess formation

Edematous, red and fluctuation indicating Subperiosteal abscess formation.

As the Subperiosteal abscess formed, signs of inflammation followed rapidly. The extremity is held in semiflexion. Surrounding muscles are in spasm . Passive movement is resisted

An increase effusion in the adjacent joint proves in most cases to be a sympathetic synovitis with sterile clear fluid. Hydroarthrosis should not be confused with septic arthritis.

It is important to remember that the metaphysis lie within the joint capsule of the hip, shoulder, ankle. Therefore these joints can develop septic arthritis by extension of Osteomyelitis.

If the infection and septicemia proceeded unabated, the patient may have toxic shock syndrome.



1. Cellulites (wide spread superficial redness and lymphangitis). 2.Acute suppurative arthritis.

3.Acute rheumatism (flitting joint pain).4.Sickle-cell crisis.5.Gauchers’ disease.

The white blood cell count will show a marked leulocytosis as high as 20,000 or more. The blood culture demonstrates the presence of bacteremia, the blood must be taken when the patient has a chill, especially when there is a spiking temperature.


Aspiration. The point of maximal tenderness should be aspirated with a large-bore needle.

Any material aspirated should be gram stained and cultured to determine the sensitivity to antibiotics.

C - reactive protein : is specific for the diagnosis with high reading.

x-ray films are negative within 1-2 weeks, Although carefully comparison with the opposite side may show abnormal soft tissue shadows.

It must be stressed that x-ray appearances are normal in the acute phase. There are little value in making the early diagnosis.

Radiography not appear till after 3 weeks. decrease bone density moth eaten. later on new bone formation.


Early diagnosis depends on followings:

4.WBC count is as high as 20,000 or more . 5.Every effort must be made to obtain a bacterial culture and determinate the sensitivity to antibiotics. Tc99m scanning. CT or MRI.

1.General treatment: nutritional therapy or general supportive treatment by intaking enough caloric, protein, vitamin etc. 2. antibiotics therapy. 3.surgical treatment . 4.immobilization .

The prompt administration of antibiotics is so vital that the result need not be waited, usually using wide-spectrum antibiotics, even by intravenous administration during the first 1-3 days.

The choice of antibiotics may subsequently be modified according to culture, sensitivity results, and clinical response. The treatment should be continued for at least 2 weeks after the body temperature is down to the normal in order to minimize the possibly of reoccurrence.

As any infection in a closed space, immediate provision of drainage is of paramount importance. This must be done at earliest possible opportunity even before signs of Subperiosteal abscess is evident. To wait is to invite disaster.

Surgery is indicated when there has been no response to vigorous antibiotics treatment after 48-72 hours.

Surgery is achieved by making a window in the bone cortex to decompress rather than debridement.

Spread septicemia. Persistant infection (chronic). Growth disturbance shortening or deformity. . suppurative arthritis: (in young children in intracapsular metaphysis.).

Subacute haematogenous Osteomyelitis.

Osteomyelitis may present in mild form. Organism may be low virulent. The distal femur ,proximal ,distal tibia are the favorite site.



The patient usually is child with pain near one of the large joint for weeks. X ray typical osteolytic lesion of small ,oval cavity surrounded with sclerosis.. Rx open with antibiotics

If any of sequestrum, abscess cavity, sinus tract or cloacae is present. Hematogenous infection with an organism of low virulence may be present by chronic onset.

The imprisoned sequestra provoke a chronic seropurulant discharge which escapes through a sinus . Bacteria may remain dormant for years. Giving rise to recurrent flares of acute infection.

M. O.

Stap.aureus. E coli. Stap .pyogenes. Proteus and pseudomonas. Stap epidermis.

Causes:

1.post acute infection. 2.post operative infection. 3.Compound fracture. 4.Chronic infection from the start as in T. B. 5.osteomyelitis of garea.

Pathology

1.Bone is destroyed or devitalized. 2.Cavities containing pus and pieces of dead bone (sequestrum).

3.Sinuses . 4.Involucrum. 5.Pathological fracture.

Clinical features
During the period of inactivity, no symptoms are present. Only Skin-thin, dark, scarred, poor nourished, past sinus, an ulceration that is not easily to heal. Muscles-wasting contracture, atrophy


Joint-stiffness Bone-thick, sclerotic. often contain abscess cavity

At intervals, a flare-up occurs. The relapse is often the result of poor body condition and lower resistance. A lighting up of infection is manifested by aching pain that is worse at night.

Locally there will be some heat. Swelling. Redness. Tenderness. Edema.

Because pus may build up in cavity, then a sinus may open and start to exudates purulent materials and small sequestrum. The sinus closed and the infection subsided.

X-ray findings

Bone resorption=cavitation. Sclerosis . Sequestrum. Pathological fracture may be present.


E S R increased. WBC may be increased. culture from the sinus. A sinogram may help to localize a particular focus of infection. Bone scans are useful in revealing hidden foci and inflammatory activity.
INVESTIGATIONS


It is very difficult to provide a permanent cure for chronic Osteomyelitis. most antibiotics fail to penetrate the barrier of fibrous tissue plus bone sclerosis. Chronic osteomyelitis presents quite different problem from the acute form. Its primary problem is surgical removal of all dead and poor vascularized tissues.

The operation must be carefully planed as it often means significant removal of bone and surrounding tissues. local muscle flap procedures.


The most common - Staphylococcus aureus.

The hips and knees are the most frequently affected sites.

Hematogenous spread from an infective focus. Spread from an adjacent focus (eruption of bone abscess). Direct introduction by the wound. Intra articular injection. Arthroscopy.

Causative organism:

Stap. Haemo. Influ. Less commonly strep. E-coli. proteus.

Clinical features

In newborn infants: Baby is irritable. Refuse to eat. Rapid pulse. Fever. There may be an evidence of umbilical cord infection.

In children:

acute pain in single large joint like hip. reluctance to use the limb. ill. rapid pulse. swinging fever. skin look red. joint swelling. local warmth. marked tenderness. all movement is limited

Often that the superficial joint is painful. Swollen. Inflamed. Local warmth . Tenderness. Movement is restricted.
In adults:

Investigations

X-ray in early cases is normal. Ultrasound shows joint effusion. In E-coli there may be an evidence of gas in the joint.



WBC ,E S R is increased. Blood culture positive. Examination of the joint aspirate. with gram stain.

Acute osteomyelitis.Trauma.Irritable joint (the child not ill, no sign of infection).Rheumatic fever.Haemophilic bleed.Gout and pseudogout.Gauchers’ disease.

Essential principles in the management

The joint must be adequately drained. Antibiotics must be given to diminish the systemic effects of sepsis. The joint must be rested in a stable position.

Antibiotics. The initial choice of antibiotics is based on the judgment of the most likely pathogen's. Then according the culture and sensitivity.

Drainage.

If the diagnosis is made early and the involved joint is superficial, such as the elbow or ankle. Aspiration should be performed . Repeated if necessary.

The joint should be splinted in a position of function. Patient should be observed. For a decrease in. Pain. Swelling. Temperature. And for improved joint mobility.

Although some infections clear up within days, antibiotic regimens often should be continued for 4 to 6 weeks, depending on the clinical course.


If the articular cartilage is preserved so gently and gradually increasing movement. If the cartilage is destroyed. So the aim to keep the joint immobile while ankylosis is awaited.
After care.

Complications

Epiphyseal destruction (in neglected infants). Growth disturbance. ( shortening or deformity). Ankylosis (due to cartilage damage).

Tuberculosis causes a granulomatous reaction which is associated with tissue necrosis and caesation. Mycobacterium tuberculosis (human, less commonly bovine ).enter via the lung or gut or rarely through the skin.

the initial lesion in lung, pharynx or gut, with lymphatic spread to regional lymph node.
1.Primary complex:

If the resistance to the original infection is low, wide spread dissemination via the blood stream, giving rise to miliary TB ,or meningitis.
2.Secondary spread:

Bone or joint is affected in about 5%. there is predilection to vertebral bodies, and the large synovial joints.

3.Tertiary lesion:

In endemic area skeletal t. b. is seen mainly in children. In non endemic area is seen in chronic debilitating disease (AIDS).

Once the bacilli have gained afoot hold, so chronic inflammatory reaction. Then granulomatous lesion started (giant cell surrounded with necrosis and round cell at the periphery).



Spread to soft tissue lead to cold abscess. Followed with sinus and end with secondary pyogenic infection.

These changes affected either the synovium or the bone is affected and then spread to the near by structure.

Large joint usually involved( hip ,knee, less often shoulder or ankle.

If the disease is arrested at an early stage, healing may be by resolution to normality. If the cartilage is destroyed healing by fibrosis and incomplete ankylosis.

In monoarticular atrthritis History of previous infection. The patient usually a child ,or young adult Pain . Swelling. Fever . Lassitude . Loss of weight.


Night cries (the joint splinted by muscle spasm during the day, relaxes with sleep and damage tissues are stretched). Muscle wasting. Movement in all direction limited.

In T B spine:Pain may be slight.Kyphosis (gibbus).Occasionally the presenting feature is weakness or loss of sensibility in the lower limb.In neglected cases patient presented with paralysis (pott’s paraplegia).


Soft tissue swelling, Periarticular osteoporosisBone ends ‘washed – out’.Narrowing the articular ends. Early changes:

Erosions of the subarticular cartilage. cystic changes appeared.

Later on :


T B spondylitis may appear as localized bone erosion and collapse across an intervertebral disc space. There may be soft tissue traces of paravertebral abscess.

E S R increased. Relative lymphocytosis. Mantoux test positive.

Synovial fluid aspirate (high protein). Acid fast bacilli ,cultures is positive. Synovial biopsy is more reliable.

Transient synovitis. Monoarticular rheumatoid arthritis. Subacute arthritis. Heamorrhagic arthritis.

Pyogenic arthritis. Metastatic bone disease. Multiple myeloma. Sarcoidosis.

Diagnosis
Long history. Involvement only one joint. Marked synovial thickening. Marked muscle wasting. Periarticular osteoporosis.


Main stay in RX Chemotherapy (Rifampicin, INH for 6 months) . in resistance to INH may call for pyrazinamide and streptomycin, or ethambutol.

Rest. (splintage for several months , traction).

Operation for drainage or clearance of Tuberculous abscess .

In severe deformity 

Osteotomy. Arthrodesis. Joint replacement.