Acute osteomyelitis

infection of bone

1. BONE & JOINT INFECTION

2. ACUTE OSTEOMYELITIS DENOTES INFECTION OF CORTICAL BONE & BONE MARROW ETIOPATHOGENESIS HAEMATOGENOUS SPREAD FROM DISTANT FOCI DIRECT INVASION FROM INFECTED WOUND OR JOINT ORGANISM –bacteria-most commonly STAPH AUREUS.

3. CLINICAL FEATURES SEEN 7-10 DAYS AFTER ONSET OF INFECTION PAIN, FEVER,CHILL SOFT TISSUE SWELLING, REDNESS

4. X-RAY FINDING SWELLING WITH EDEMA &BLURRING OF FAT PLANES SMALL SINGLE OR MULTIPLE LUCENCY AFFECTING METAPHYSES ELAVATION OF PERIOSTEUM &LAYERED NEW BONE FORM PERIOSTEAL REACTION –LAMELLAR OSTEOPENIA IN SURROUNDING BONE DUE TO HYPERAEMIA

5. MRI FINDINGS HIGHLY SENSITIVE IMAGING MODALITY OF CHOICE IN EARLY STAGE SHOWS LOW SIGNAL INTENSITY ON TI &HIGH SIGNAL INTENSITY ON T2 &FAT SUPPRESSED & STIR SEQ SHOWS POST CONTRAST ENHANCEMENT INTRAOSSEOUS,SUBPERIOSTEAL & SOFT TISSUE ABCESS IF PRESENT APPEAR AS WELL CIRCUMSCRIBED AREA OF LOW SIGNAL ON T1 HIGH SIGNAL ON T2 &SHOWING RIM ENHANCEMENT

6. USG SHOWS COLLECTION OF FLUID IN THE AREA BENEATH PERIOSTEUM

7. BRODIES ABCESS A SUBACUTE LOCALISED TYPE OF OSTEOMYELITIS,FOUND IN CANCELLOUS TISSUE NEAR END OF BONE. CAUSED BY ORGANISMS OF LOW VIRULENCE . ON XRAY-WELL CIRCUMCSRIBED AREA OF BONE DESTRUCTION HAS A SURROUNDING ZONE OF REACTIVE SCLEROSIS SOMETIMES ACCOMPANIED BY PERIOSTEAL REACTION

8. CT DEMONSTATES CENTRAL NECROSIS & SEQUESTRATION OF THE LESION WITH LOCAL SURROUNDING SCLEROSIS MRI SHOWS HYPERINTENSE NIDUS ON T2 WITH SCLEROTIC RIM.

9. CHRONIC OSTEOMYELITIS RESULTS FROM INADEQUATELY TREATED OSTEOMYELITIS FROM INFECTION FOLLOWING COMPOUND FRACTURE IATROGENIC CAUSE –JT REPLACEMENT &INTERNAL FIXATION OF FRACTURE INFECTION WITH MYCO. TUBERCULOSIS &TREP PALLIDUM

10. CLINICAL FEATURES PAIN ,LOCAL SWELLING PUS DISCHARGE &SINUS FORMATION SYSTEMIC SYMPTOMS-FEVER & MALAISE

11. PATHOGENESIS DIRECT INVASION OF SYNOVIAL MEMBRANE BYPENETRATING WOUND,POSTSURGICAL JOINT REPLACEMENT INFECTION OF ADJACENT TISSUE HEMATOGENOUS SPREAD FROM BLOOD BORNE INFECTION SPREAD FROM OSTEOMYELITIS

12. FEATURES OF CHRONIC OSTEOMYELITIS INVOLUCRUM-THICK PERIOSTEUM AROUND INFECTED BONE SEQUESTRUM- PIECE OF DEAD INFECTED BONE CLOACAE-OPENING IN CORTEX THROUGH WHICH PUS ESCAPE

13. X RAY FINDINGS SCLEROTIC & LUCENT AREA ADMIXED WITH BONE THICKENING IRREGULARITIES & DEFORMITIES SEQUESTRUM REMAIN AS AVASCULAR ISOLATED SEGMENT DENSER THAN SURROUNDING BONE SINUS TRACT – SEEN AS ALUCENT TRACK EXTENDING IN CONTIGUITY FROM MEDULLARY CAVITY WITH DISRUPTION OF CORTEX.

14. CT FINDINGS CT ADDS GREATER ANATOMICAL DETAIL TO CHANGES IN CHRONIC OSTEOMYELITIS SEQUESTRA REMAIN AS HIGH ATTENUATION SPICULES OF BONE IN AREAS OF OSTEOLYSIS CLOACAE, PERIOSTITIS & LOCAL SOFT TISSUE MASSES ARE WELL DEPICTED

15. MRI DEVITALISED BONE SHOW LOSS OF SIGNAL & DOES NOT ENHANCE . SINUS TRACT SEEN AS A LINEAR AREA OF LOW SIGNAL ON T1W & HIGH SIGNAL ON T2W & STIR IMAGES. SOFT TISSUE INFLAMMATION SEEN AS BRIGHT SIGNAL ON T2, SHOWING ENHANCEMENT AFTER CONTRAST

16. SCLEROSING OSTEOMYELITIS OF GARRE A RARE TYPE OF CHRONIC OSTEOMYELITIS IN CHILDREN &YOUNG ADULTS PRESENTING WITH INSIDIOUS ONSET OF PAIN SYMPTOMS RECUR AT INTERVALS & THE SUBSIDE GRADUALLY RADIOLOGICAL APPEARANCE IS THAT OF INTENSE SLEROSIS RESULTING IN THICKENED BONE.AREAS OF FRANK BONE DESTRUCTION RARE

17. PYOGENIC ARTHRITIS ARTHRITIS OF INFECTIVE ORIGIN MOST COMMONLY BY STAPHYLOCOCCUS, STREPTOCOCCUS

18. PATHOGENESIS FORMn OF PUS IN BONE DEPRIVES LOCAL CORTEX & MEDULLA OF BLOOD SUPPLY DEAD BONE RESORBED BY GRANULATION TISSUE PIECES OF BONE NOT RESORBED REMAIN AS SEQUESTRA SEQUESTRA BEING DEVITALISED REMAIN DENSER THAN SURROUNDING BONE INVOLUCRUM FORM BENEATH VITAL PERIOSTEUM ELEVATED BY PUS IN AREA OF DEAD PERIOSTEUM, DEFECTS IN INVOLUCRUM OCCURS-RESULTING IN CLOACA CLOACA ALLOW PUS & SEQUESTRUM TO ESCAPE VIA SINUS

19. IMAGING XRAY ARTHROGRAPHY USG CT MRI

20. XRAY MODALITY OF CHOICE FOR INITIAL EVALUATION EARLY FINDINGS-JOINT EFFUSION,SOFT TISSUE SWELLING,PERIARTICULAR OSTEOPOROSIS DUE TOHYPERAEMIA, LATE FINDINGS-MARGINAL &CENTRAL EROSION OF SUBCHONDRAL BONE,SUBLUXATION,DISLOCATION,JOINT SPACE REDUCTION&BONY ANKYLOSIS

21. ARTHROGRAPHY RADIOGRAPHS OBTAINED AFTER CONTRAST INJECTION REVEAL- DESTRUCTION OF ARTICULAR CARTILAGE HYPERTROPHY OF SYNOVIUM IRREGULAR JOINT CAPSULE IN CHRONIC INFECTION

22. ULTRASOUND SENSITIVE TECHNIQUE FOR DEMONSTRATING EFFUSION

23. CT USED TO GUIDE JOINT ASPIRATION CT FINDINGS INCLUDE-JOINT EFFUSION,IRREGULARITY &NARROWING OF JOINT ,SOFT TISSUE SWELLING, SUBBCHONDRAL BONE DESTRUCTION &ARTICULAR EROSION

24. MRI OVERTLY SENSITIVE HOWEVER EXPENSIVE EARLY STAGE SHOWS DISTENSION OF JOINT WITH FLUID WHICH APPEARS HYPERINTENSE ON T2 LATER STAGE SHOWS CARTILAGE DESTRUCTION,JT SPACE REDUCTION,SPREAD OF INFECTION TO ADJACENT BONE &SOFT TISSUE

25. POTT”S SPINE MOSTFREQUENT SITE OF BONE INVOLVEMENT BY TUBERCULOSIS DEFINED AS AN INFECTION BY mycobacterium tuberculosis. OF ONE OR MORE OF THE EXTRADURAL COMPONENTS OF SPINE- VERTEBRA,IV DISC,PARASPINAL SOFT TISSUE &EPIDURAL SPACE.

26. PATHOGENESIS SPREAD USUALLY BY THE HEMATOGENOUS ROUTE BY PERIVERTEBRAL ARTERIAL OR VENOUS PLEXUS, ARTERIAL BEING MORE COMMON INFECTION BEGINS IN CANCELLOUS AREA OF VERTEBRAL BODY, COMMONLY IN PARADISCAL LOCATION.VERTEBRA BECOMES SOFT & EASILY COMPRESSED TO PRODUCE WEDGING OR COLLAPSE.DISC RESIST INFECTION UNTIL LATE AS DISC IS AVASCULAR

27. CLINICAL FEATURES CAN OCCUR AT ANY AGE, BUT MAJORITY <30 YRS FEVER,MALAISE , NIGHT SWEATS PERSISTENT SPINAL PAIN, LOCAL TENDERNESS,LIMITATION OF SPINAL MOBILITY LOWER THORACIC &LUMBER VERTEBRA MOST COMMONLY AFFECTED FOLLOWED BYMID THORACIC & CERVICAL VERTEBRA

28. CLINICAL FEATURES cont PARAPLEGIA-EARLY ONSET DUE TO CORD EDEMA ,CORD COMPRESSION BY EPIDURAL ABCESS OR GRANULATION TISSUE,PATHOLOGICAL SUBLUXATION OR DISLOCATION,SEQUESTERED BONE OR DISC FRAGMENTS LATE ONSET DUE TO DURAL FIBROSIS, SEVERE KYPHOSCOLIOTIC DEFORMITY,SPINAL CANAL STENOSIS& SEQUESTRA FROM VERTEBRAL BODY

29. XRAY USUAL INITIAL INVESTIGATION BUT OFTEN NEGATIVE IN EALY DISEASE. DEPENDING ON LOCATION FINDINGS ON XRAY- PARADISCAL –MOST COMMON TYPE BEGIN IN ANTERIOR PART OF VERTEBRAL SUPERIOR INFERIOR ADJACENT TO ENDPLATE

30. XRAY FINDINGS contd DEMINERALISATION & LOSS OF DEFINITION OF DENSE MARGIN OF ENDPLATE WITH LITTLE PERIOSTEAL REACTION OR SCLEROSIS AS INFECTION SPREADS, ADJACENT IV DISC GETS INVOLVED WITH NARROWING OF DISC SPACE WITH FURTHER PROGRESSION ATERIOR WEDGING OR COLLAPSE OCCUR RESULTING IN KYPHOSIS

31. STARTS IN CENTRAL PART OF VERTEBRAL BODY SHOWS A LYTIC AREA WITH ABSENCE OF NORMAL TRABECULAE IN CENTRAL PORTION AWAY FROM DISC MARGIN GRADUALLY ENLARGES CAUSING BALLOONING OF VERTEBRAL BODY. IN LATER STAGE CONCENTRIC COLLAPSE OCCUR RESEMBLING VERTEBRA PLANA DISC SPACE MINIMALLY AFFECT

32. APPENDICEAL OR NEURAL ARCH NEURAL ARCH INVOLVEMENT IN 2-30%OF CASES IN CONTIGUITY WITH VERTEBRAL BODY INVOLVEMENT COMMONLY AFFECTS CERVICAL & UPPER DORSAL SPINE TENDENCY TOWARDS PEDICLE &LAMINA INVOLVEMENT XRAY SHOWS PEDICULAR OR LAMINA DESTRUCTION, EROSION OF ADJACENT RIBS OR POSTERIOR CORTEX OF VERTEBRAL BODY WITH RELATIVE SPARING OF DISC.PARASPINAL MASS + .

33. ABCESS PRODUCE SOFT TISSUE OPACITY ON XRAY ,OPACITY OFTEN BILATERAL . GLOBULAR ABCESS DENOTES PUS UNDER TENSION ABCESS IN CERVICAL REGION CAUSE WIDENING OF PREVERTEBRAL TISSUE DORSAL SPINE ABCESSS CAUSE LATERAL DISPACEMENT OF POSTEROMEDIAL PLEURAL LINE IN LUMBER REGION ABCESS SEEN TO TRACK ALONG PSOAS PRODUCING BULGING OF PSOAS OTLINE ON XRAY

34. CT HELPS IN EARLY DETECTION OF BONE &SOFT TISSUE BETTER ANATOMIC LOCALISATION & CHARACTERISATION OF LESION. PROVIDE GUIDANCE FOR BIOPSY & SURGICAL APPROACH HOWEVER LESS USEFUL THAN MRI AS EARLY INFLAMMATORY CHANGES ARE NOT WELL DEPICTED,SOFT TISSUES POORLY DELINEATED

35. CT FINDINGS ON CT 4 PATTERNS DESCRIBED FRAGMENTARY- 47%,MOST COMMON SHOWS NUMEROUS SMALL BONE FRAGMENTS IN SOFT TISSUE MASS OSTEOLYTIC- 33% SUBPERIOSTEAL-10% WELL DEFINED LYTIC WITH SCLEROTIC MARGIN OBLITERATION OF FAT PLANE IS SEEN IN ABCESS FORMATION. DISC SPACE NARROWING, KYPHOSIS & CHANGES SEEN ON XRAY WELL DEPICTED

36. MRI HAS HIGH SENSITIVITY OF EARLY BONE INVOLVEMENT & EDEMA, FOR ASSESMENT OF SPINAL CORD OR NEURAL INVOLVEMENT INCLUDING ENDPLATE CHANGES & MARROW INFILTRATION. SKIP BONE LESIONS, EPIDURAL,MENINGEAL &CORD INVOLVEMENT MORE CLEARLY DEPICTED ON MRI

37. MRI FINDINGS T1W IMAGE SHOWS HETEROGENOUS DECREASE SIGNAL INTENSITY IN AFFECTED VERTEBRA &LOSS OF CORTICAL DEFINITION ON T2W IMAGE HETEROGENOUS INCREASED SIGNAL INTENSITY PARASPINAL SOFT TISSUE MASSES SEEN WITH LOSS OF SIGNAL INTENSITY SHOWING POSTCONTRAST THICK RIM ENHANCEMENT. ON T2 PARASPINAL MASS APPEAR HYPERINTENSE EPIDURAL EXTENSION WELL DEPCTED SEEN IN ABOUT 60% INVOLVED VERTEBRA. POST CONTRAST FAT SUPPRESSED T1 SEQ BEST TO DEMONSTRATEMENINGEAL & EPIDURAL INFLAMMATORY SOFT TISSUE

38. TUBERCULAR ARTHRITIS TUBERCULAR ARTHRITIS USUALLY AFFECTS MAJOR JOINTS – HIP & KNEE MULTIFOCAL INFECTION RARE INFECTION MAY BE SYNOVIAL OR SECONDARY TO BONE DISEASE.THE LATTER FACILITATED AS EPIPHYSEAL PLATE OFFER LITTLE RESISTENCE.

39. TUBERCULOSIS OF HIP LESIONS COMMONLY ARISE IN ACETABULUM, SYNOVIUM, FEMORAL EPIPHYSIS OR METAPHYSISSPREAD OR SPREAD FROM FOCI IN GREATER TROCHANTER OR ISCHIUM.

40. STAGE OF SYNOVITIS IN EARLY SYNOVITIS . SOFT TISSUE SWELLING & JOINT WIDENING OCCUR DUE TO EFFUSION PT PRESENTS WITH IRRITABLE HIP DISPLACEMENT OF FAT PLANES & POSIVE OBTURATOR SIGN DUE TO FLEXION DEFORMITY FIRST RADIOLOGICAL SIGN MAY BE JUXTAARTICULAR OSTEOPOROSIS

41. STAGE OF ARTHRITIS DEFORMITY OF HIP JOINT IS PRESENT IN ADDITION TO OSTEOPOROSIS LOCALISE EROSION SEEN IN PERIARTICULAR REGION DESTRUCTION OF ARTICULAR CARTILAGE LEADS TO EROSION OF ACETABULAR MARGIN & FEMORAL HEAD WITH REDUCTION OF JOINT SPACE.

42. STAGE OF ADVANCED ARTHRITIS WITH FURTHR PROGRESSUION . DESTRUCTION OF , CAPSULE & LIGAMENTS OCCUR RTICULAR CARTILAGE, ACETABULUM, FEMORAL HEAD