OSTEOMYELITIS - Disease Management

Osteomyelitis is an infection of the medullary bone that results in progressive inflammatory destruction of the bone and the apposition of new bone, caused by aerobic and anaerobic bacteria, mycobacteria, and fungi. Osteomyelitis occurs in vertebrae and bones of the feet in patients with diabetes or at sites of bone trauma or surgery. In children, osteomyelitis usually affects the metaphysis of the tibia or femur as well as growing bones with a rich blood supply.

Classification

• Hematogenous osteomyelitis is an infection caused by bacterial seeding from the blood.
• Direct or contiguous inoculation osteomyelitis-is caused by direct contact of the tissue and bacteria during trauma or surgery.
• Chronic osteomyelitis
• Osteomyelitis secondary to peripheral vascular

Causes

Bacterial causes of acute and direct osteomyelitis include

the following:

• Acute hematogenous osteomyelitis
• Newborns (younger than 4 months): S. aureus, Enterobacter species, and group A and B Streptococcus species
• Children (aged 4 months to 4 yr): S. aureus, group A Streptococcus species, Haemophilus influenzae, and Enterobacter species
• Children, adolescents (aged 4 yr to adult): S. aureus (80%), group A Streptococcus species, H influenzae, and Enterobacter species
• Adult: S. aureus and occasionally Enterobacter or Streptococcus species
• Direct osteomyelitis
• Generally: S. aureus, Enterobacter species, and Pseudomonas species
• Puncture wound through an athletic shoe: S aureus and Pseudomonas species
• Sickle cell disease - S. aureus and Salmonellae species

Riek Factors

• sickle cell disease
• Local trauma
• Neuropathy
• Vascular insufficiency IV drug use
• Presence of orthopedic implant
• Other conditions that predispose to bone infarcts
• Hemodialysis
• Open fractures
• Diabetes mellitus

Signs and Symptoms

• Fatigue
• Malaise
• Tenderness
• Febrile
• Afebrile
• Nonhealing ulcer
• Restriction of movement
• Hematogenous long-bone osteomyelitis
• Abrupt onset of high fever
• Local edema, erythema, and tenderness
• .Hematogenous vertebral osteomyelitis
• History of an acute bacteremic episode
• .May be associated with contiguous vascular insufficiency
• Local edema, erythema, and tenderness
• Localized back pain with a paravertebral muscle spasm that is unresponsive to conservative treatment.
• Acute osteomyelitis of peripheral bones
• Localized warmth, swelling, erythema, and tenderness.
• Irritability
• Insidious onset
• Sinus drainage.
• Weight loss and fatigue
• Chronic osteomyelitis
• Sinus tract drainage
• Low-grade chronic osteomyelitis
• Intermittent (months to many years) bone pain
• Chronic fatigue
• Malaise

DIAGNOSIS

Differential Diagnosis

• Cellulitis
• Hand Infections
• Gout and Pseudogout Sickle Cell Disease
• Spinal Cord Infections
• Gas Gangrene
• Neoplasma
• sickle cell disease

Investigations

• WBC count
• ESR
• CBC
• C-reactive protein
• CT
• X-rays
• Bone biopsy
• Radiograph
• Radioisotope bone scans
• Blood culture results
• MRI

TREATMENT

Goal

• To eliminate the infection and prevent the development of chronic infection

Pharmacological Treatment

Hematogenous

• Nafcillin, oxacillin, cefazolin, vancomycin.Sickle cell
• Ciprofloxacin, levofloxacin, ofloxacin, cefotaxime,Ceftriaxone.

Contiguous without vascular insufficiency

• Nafcillin or cloxacillin and ciprofloxacin or vancomycin and ceftazidime

Contiguous with vascular insufficiency

• Imipenem, meropenem

Surgical Treatment

• In chronic infection, surgical removal of the dead bone tissue is indicated. The open space left by the removed bone tissue may be filled with bone graft, or by packing material to promote the growth of new bone tissue. Antibiotic therapy is continued for at least 3 weeks after surgery.
• The infection of an orthopedic prosthesis may require surgical removal with debridement of the infected tissue surrounding the area. A new prosthesis may be implanted in the same operation, or delayed until the infection has resolved, depending on its severity.

PATIENT EDUCATION

• Avoid further stress and weight-bearing until healing.

Complications

• Bone abscess
• Loosening of the prosthetic implant
• Overlying soft-tissue cellulitis
• Draining soft-tissue sinus tracts
• Local spread of infection
• Reduced limb or joint function
• Bacteremia
• Fracture

Prognosis

The prognosis is variable but markedly improved with timely diagnosis and aggressive therapeutic intervention. The outcome is usually good with adequate treatment of acute osteomyelitis, and worse for chronic osteomyelitis, even with surgery. Resistant or complicated chronic osteomyelitis may result in amputation.