How the microorganisms enter the body?

Microorganisms may enter and infect the bone by any of the following three routes:

 Haematogenous route: Most common entry through the bloodstream, common in children (osteomyelitis)

Direct route: Directly through the neighbouring infected tissue (septic arthritis)

 Exogenous route: Through open fracture, open wound, surgical incision, etc.

Types of osteomyelitis

Their are three types of osteomyelitis. To know more about bone then see 

Acute Haematogenous osteomyelitis

Acute haematogenous osteomyelitis is mostly caused by S. aureus. Streptomyces albus or streptococcus. It occurs most commonly during active growth, i.e., between 3 and 16 years of age. The causative organisms spread through the bloodstream from the original focus such as tonsils, respiratory tract and intestines to the bone.

Clinical features

The onset of Osteomyelitis symptoms may be preceded by a history of trauma to the affected part, in the acute stage presents with high fever, headache, irritability and mild swelling. The diagnosis is important and is done clinically. Some visible osteomyelitis symptoms are,

• A primary focus of infection in the body, e.g., skin and tonsils.
• On examination, signs of dehydration may be found.
• Tenderness and signs of inflammation are present over the metaphysis.
• Swelling may become apparent when the pus comes into a muscular or subcutaneous plane.
• In rare cases, there may be signs of toxaemia.

Investigations

The following investigations may help in osteomyelitis diagnosis, though they may not be specific.

1. Blood

 (a) Leucocytosis should be up to 20,000 cells.

 (b) Erythrocyte sedimentation rate (ESR) level is elevated.

(c) Blood culture may be positive for the organism.

2. Radiograph of the affected part

(a) The radiograph is usually normal in the first week.

(b) A periosteal reaction may be seen between 7 and 10 days.

3. Bone scan:

It shows an increased uptake by the affected bone.

Treatment

The successful Osteomyelitis Treatment involve its early diagnosis with conservative treatment, surgical treatment and physiotherapy intervention.

Conservative treatment

• Antibiotics: Appropriate antibiotics are administered intravenously.
• Rest and proper positioning of the limb (area of infection) with a suitable POP cast with the limb elevated
• The patient should have an adequate balanced diet and proper fluid intake.
• Regular monitoring of the general condition, fever, pulse and the state of hydration, etc., has to be done.
• Observe edemas, redness of skin, warmth, soft tissue abscess and discharge, etc.
• If the patient is anaemic, then IV fluids are administered in case of dehydration.

Surgical treatment

If there is no response from conservative treatment within 48 hr then surgery is advised. For the incision and drainage of pus from the subcutaneous abscess, multiple holes are drilled into the cortex of the bone for proper drainage of the pus. Sometimes, a small window may be made in the cortex of the bone for better drainage

Exogenous osteomyelitis

Exogenous osteomyelitis is a type in which a microorganism enters through an open wound, an open fracture or following surgery. It can be prevented by early surgical intervention.

Chronic osteomyelitis

Acute osteomyelitis if treated abnormally can lead to chronic osteomyelitis. Another cause can be the weak immunity of the host, it can be due to malnutrition.

Clinical features

• Discharging sinus
• Irregular thickening of the bone
• The irregular surface of the bone
• Deformity of the limb
• Shortening of the limb
• Joint stiffness

Chronic osteomyelitis Treatment

The successful Chronic osteomyelitis treatment involves its early diagnosis with conservative treatment, surgical treatment and physiotherapy intervention.

Antibiotics: Antibiotics are given as per the pus culture and sensitivity reports.

 Surgical operations: The following surgical operations are performed either singly or in combination.

Sequestrectomy: Removal of the necrotic bone (sequestrum) with curettage of the cavity is carried out.

Curettage: The cavity in the bone allows accumulation of pus and bacteria inside it. The cavity is curetted and after a thorough curettage, it may be filled with cancellous bone grafts or a viable muscle.

Saucerization: Pus gets collected in the deep cavity of the bone. The cavity is therefore made shallow like a ‘saucer’, by removing its overhanging edges which prevents accumulation of pus. This procedure is called sauterization.

Excision of the sinus tract: The sinus tract is excised and the wound is allowed to heal slowly.

Amputation: It is done in rare cases where organs get affected due to injection.

Subacute osteomyelitis

Subacute osteomyelitis is of three types: Salmonella osteomyelitis, Brodie abscess and  Sclerosing osteomyelitis of Garre.

Clinical features

• Chronic dull pain over the site of the lesion (usually tibia) which worsens at night.
• Deep bony tenderness
• No discharging sinus

Treatment

Successful bone infection treatment involves its early diagnosis with conservative treatment, surgical treatment and physiotherapy intervention.

• Antibiotics
• Excision of the thickened bone
• Differentiation from Ewing sarcoma, osteosarcoma, or osteoid osteoma which have a similar radiographic picture.