acuteosteomyelitis-.pptx
- 2. ⦁ Osteomyelitis is the inflammation of the bone or BM caused by an infecting organism. ⦁ Micro-Organisms may reach bones via the Bloodstream or by Direct Invasion. (e.g : skin puncture, operation, open fracture) ⦁ Factors which affects it’s development ◦ Virulence of the organism involved ◦ Host Factors (Age, Immunity, Diseases) ◦ Local factors (site of Involvement, damaged muscle presence of foreign material , vascularity)
- 3. ⦁ It can be classified on the basis of the causative organism, the route, duration and anatomic location of the infection. ⦁ In children, osteomyelitis MC – long bones of UL & LL ⦁ Adults - vertebrae. ⦁ Diabetic- feet if they have foot ulcers. ⦁ Osteomyelitis usually begins as an acute infection, but it may evolve into a chronic condition.
- 4. Types: ◦ Acute ◦ Sub- acute – insidious onset ◦ Chronic – lower grade recurring infection
- 6. ⦁ Overall Most common - Staph. aureus ⦁ H. Influenza infection has become less common due to vaccination. ⦁ Sickle-Cell disease- Salmonella ⦁ IV drug abusers- Pseudomonas, Klebsiella ⦁ chronically ill patients - Fungal OM
- 7. 1. Hematogenous • Bacterial seeding from the blood. • Seen primarily in Children. • The most common site: Metaphysis at the growing end of Long Bones in Children Vertebrae in Adults; involving two adjacent vertebrae with intervertebral disk (may occur pelvis, long bones and clavicle) 2. Direct Inoculation Osteomyelitis • Its osteomyelitis complicating open fracture or surgical operation, in which organisms gain entry directly through the wound. • Tend to involve multiple organisms, but mainly S.Aureus
- 8. PATHOMECHANISM Organisms reach the bone through the blood stream from a septic focus elsewhere in the body – for instance from a boil in the skin. Infection begins in the metaphysis of a long bone, which must be presumed to form a productive medium for bacterial growth. Acute inflammatory reaction occurs Pus is formed and soon finds its way to the surface of the bone where it forms a subperiosteal abscess Later the abscess may burst into the soft tissues and may eventually reach the surface to form a sinus. Blood supply to a part of the bone is cut off by septic thrombosis ofthe vessels . The ischaemic bone dies and eventually separates from the surrounding living bone as a sequestrum. New bone is laid down beneath the stripped-up periosteum, forming an investing layer known as the involucrum.
- 10. 1. Inflammation. • Earliest Change • Increase interaosseous pressure leads to Pain. 2. Suppuration • Pus at medulla >> Volkmann canals>>Surface >> Subperiosteal Abscess>> spread along the shaft>> burst into the soft tissue • May extend to Epiphysis in Neonates and Children. • May extend to Interverteberal Discs in Adults. 3. Necrosis/Sequestrum • Begin in a week. • causes : increase in intraosseous pressure, vascular stasis, infected thrombosis, periosteal stripping which increasingly compromise blood supply
- 11. 4. New-bone formation • New bone formation from the stripped surface of periosteum • Bone thickens to form an involucrum enclosing the infected tissue. 5. Resolution bone will heal if infection is controlled and intraosseous pressure is released, though it may remain thickened. or progress to complications
- 13. ⦁ Fever, chills and Malaise ⦁ Pain ⦁ Tenderness, Redness, Edema, Warmth(signs of inflammation) ⦁ Restricted Joint Movement History preceding - Skin Lesion or Sore Throat. Typically: male child. most commonly - tibia, the femur and the humerus. Rapid onset. The child complains of feeling ill, and of severe pain over the affected bone. There may be a history of recent boils or of a minor injury.
- 14. 1. Lab studies • CBC: leucocytosis • Elevated CRP & ESR (nonspecific). • Blood Culture • Culture & sensitivity test; by aspiration from the subperiosteal abscess, +ve in only 50% of patients with hematogenous osteomyelitis. 2. Radiological studies • X-ray • MRI • Radionuclide bone scanning • CT scan • US
- 15. • 7 – 10 days : localized soft tissue swelling adjacent to metaphysis obliteration of fat planes permeative metaphyseal osteolysis(single/multiple) • 10 – 14 days: Intra-cortical fissuring Elevation of periosteum, Endosteal erosion • 3 – 6 weeks: layered new bone formation periosteal reaction (lamellar/nodular) INVOLUCRUM (20 days) cloak of laminated/ spiculated periosteal reaction SEQUESTRUM (>30 Days) Cloaca – space in dead bone
- 17. Plain-film radiograph showing osteomyelitis of the 2nd metacarpal • Periosteal elevation • Cortical disruption • Medullary involvement.
- 18. ⚫ X-ray of the left ankle of a 10-year-old boy shows: ⚫ Lucency in the tibial metaphysis secondary to acute hematogenous osteomyelitis (AHO).
- 19. MRI sensitivity 90-100% BM appears hypo on T1W hyper on T2W/ f.s T2W/ STIR Post T1 +C enhancement Subperiosteal infection – hyper halo around cortex on T2 W Abscess - Hypo: T1; Hyper : T2; rim enhanced+ Adjacent Soft tissue- increased signal intensity on T2W Modality of choice for early Diagnosis of OM
- 20. MRI sagittal section shows the same AHO lesions with the right lesion extending into the growth plate.
- 21. Bone Scintigraphy • A 3-phase bone scan with technetium 99m is probably the initial imaging modality of choice – within 3 days. VS reserved for the diagnosis of bone infection in the less clinically accessible sites such as the hip, pelvis and spine. • Show increase activity(non specific sign of inflamation). Accumulation of isotope depends upon the rate of bone turnover and its vascuarity, so that in the early stages of disease inadequate blood supply may result in a ‘cold’ lesion. More commonly, within a few hours or days of the onset of symptoms there is an increased uptake of isotope, giving a ‘hot’ scan at the site of the bone lesion.
- 22. Ga-67: 100% sensitivity, increased uptake more useful for c/c OM Tc99: triple phase - 1st phase : Blood flow 2nd phase : blood pool of inflammed region 3rd phase: Bone uptake, 2-4 hrs after administration. False +ve : Degenerative disease, healing fracture, loose prosthesis False –ve : within 1st 48hrs, cold d/t vasospasm WBC scan,Tc-99, In111 improved photon __ + dosimetry hence replaced Ga
- 23. A. Anterior view B. lateral view Both showing the accumulation of radioactive tracer at the right ankle (arrow). This focal accumulation is characteristic of osteomyelitis.
- 24. CT scan Marrow density - >+/- 20HU difference to healthy bone suggestive of marrow infection • Spinal vertebral lesions • Complex anatomy (pelvis, sternum & calcaneus)
- 26. Ultrasound • In children with acute osteomyelitis. • May demonstrate early changes, 1-2 days after onset of symptoms. • Shows soft tissue abscess, sinus tract, fluid collection & periosteal elevation • Ultrasonography allows for ultrasound-guided aspiration. • It does not allow for evaluation of bone cortex.
- 27. ⦁ Criteria (2 of 4): 1. Localized classic physical findings (tenderness, erythema or edema). 2. Purulent material on aspiration of affected bone. 3. Positive findings of bone tissue or blood culture. 4. Positive radiological imaging study.
- 28. 1. Analgesia 2. Rest of the affected part 3. Antibiotic treatment. 🞄 IV antibiotics for 1-2 weeks then oral for 3-6 weeks. 🞄 Cultures & sensitivity test. 🞄 Why systemic ? To ensure high blood levels. 🞄 Initially broad-spectrum antibiotics such as a third- generation cephalosporin combined with a synthetic penicillin is used, but as soon as the causative organism has been identified the antibiotic to which it is most sensitive should be ordered. 🞄 MRSA- Use vancomycin instead of the penicillin. 🞄 Antibiotics should be continued for at least 4 weeks, even when the response has been rapid.
- 29. Nade in 1983 proposed 5 principles for Acute hematogenous OM that are still applicable. 1. Appropriate antibiotic is effective before abscess formation 2. Antibiotics do not sterilise avascular tissues or abscess, these require surgical removal. 3. If such removal is effective, antibiotics prevents its reformation. 4. Surgery shoul not damage further ischaemic bone and soft tissue. 5. Antibiotics to be continues after surgery.
- 30. ◦ Debridement ◦ Drainage of subperiosteal abscess ◦ Operation may be unnecessary if effective antibiotic treatment can be begun within 24 hours of the onset of symptoms, but in practice diagnosis is not always so prompt, and in that event it seems wiser to undertake early operation, in order to release pus and to relieve pain, which is often severe. This should definitely be performed if there has not been a marked improvement to the antibiotic treatment within 48 hours.