Bone + Soft Tissue Infections Flashcards
What is osteomyelitis
INFECTION of BONE - specific/non-specific
non-specific most common
Acute OM presentation in infants
• MINIMAL SIGNS/may be V. ILL
- FAILURE TO THRIVE = STOP EATING
- Poss. DROWSY/IRRITABLE
• METAPHYSEAL TENDERNESS + SWELLING - unlikely to see as babies are chubby
- DECREASE ROM
- POSITIONAL CHANGE = may adopt unusual positions
• COMMONEST ~ KNEE
Acute OM presentation in children
- SEVERE PAIN
- RELUCTANT TO MOVE = NEIGHBOURING JOINT HELD FLEXED + NOT WGT. BEARING
- CAN MOVE A LITTLE BIT
- Poss. TENDER FEVER (SWINGING PYREXIA) + TACHYCARDIA
- MALAISE = FATIGUE, N & V, FRETFUL/DISTRESSED
- TOXAEMIA
Acute OM presentation in adults
- PRIMARY OM = THORACOLUMBAR SPINE commonly
- BACKACHE
- Hx of UTI/UROLOGICAL PROCEDURE
- ELDERLY, DM, IMMUNOCOMPROMISED
May have late presentation due to difficulties in differentiating bwtn this & “normal” back pain
- SECONDARY OM = MORE COMMON
- Often after OPEN FRACTURE, SURGERY (esp. ORIF)
- MIXTURE of ORGANISMS
Chronic OM presentation
Involves REPEATED BREAKDOWN of “HEALED” WOUNDS = LOTS of SINUSES
Acute OM epidemiology
- MOSTLY CHILDREN - DIFF. AGES
- BOYS > GIRLS
- Hx of TRAUMA - MINOR
- OTHER DISEASE:
- DM
- RHEMATIC ARTHRITIS
- IMMUNE COMPROMISE
- LONG-TERM STEROID TREATMENT
- SICKLE CELL
Acute OM infection source/route
- HAEMATOGENOUS SPREAD = CHILDREN & ELDERLY
- LOCAL SPREAD from CONTIGUOUS SITE of INFECTION = TRAUMA (OPEN FRACTURE), BONE SURGERY (ORIF), JOINT REPLACEMENT - SKIN PERFORATION
- SECONDARY to VASCULAR INSUFFICIENCY
infants - infected umbilical cord
children - boils, tonsillitis, skin abrasions
adults - UTI, arterial line, venous line
Chronic OM infection source/route
- May FOLLOW ACUTE OM = rare in children due to aggressive treatment
- May START DE NOVO e.g. FOLLOWING OPERATION, FOLLOWING OPEN FRACTURE (poss. Many years after initial fracture), IMMUNOSUPPRESSED, DM, ELDERLY, PWID etc.
Acute OM micro-organisms
infants < 1yr = s. aureus, group b streptococcus, e. coli (if present, often part of more widespread infection)
older children = s. aureus, strep pyogenes, h. influenzae
adults = s. aureus mainly, coagulase -ve staph, propionbacterium (joint replacements, low virulence, skin commensal), mycobacterium tuberculosis, pseudomonas aeruginosa (secondary to foot injuries, PWID)
Other:
diabetic foot + pressure sores = mixed infections incl. anaerobes
sickle cell disease = salmonella spp.
fishermen, filleter = mycobacterium marinum
debilitating illness, HIV, AIDS etc. = candida
Chronic OM micro-organisms
often mixed infection - usually same organism/s each flare up
mainly = s. aureus, e. coli, strep. pyogenes, proteus
Acute OM pathophysiology
LONG BONES = METAPHYSIS e.g. distal femur, proximal tibia, proximal humerus
JOINTS w/ INTRA-ARTICULAR METAPHYSIS e.g. hip, elbow (radial head)
1. Starts at METAPHYSIS (TRAUMA may play a role in this as it's the SHOCK-ABSORBING part of bone + has VASCULATURE running through it) 2. VASCULAR STASIS = VENOUS CONGESTION + ARTERIAL THROMBOSIS 3. ACUTE INFLAMMATION = INCREASED PRESSURE 4. SUPPURATION 5. RELEASE of PRESSURE = medulla, sub-periosteal, into joint 6. BONE NECROSIS (SEQUESTRUM) due to pus 7. NEW BONE FORMAITON (INVOLUCRUM) 8. RESOLUTION/NOT (CHRONIC OSTEOMYELITIS - permanent unless radical treatment)
Chronic OM pathophysiology
- CAVITIES, poss. SINUS/ES
- DEAD BONE (RETIANED SEQUESTRA)
- INVOLUCRUM
- HISTOLOGICAL PICTURE is one of CHRONIC INFLAMMATION
Acute OM investigations/diagnosis
• Hx & CLINICAL EXAMINATION = PULSE + TEMP.
BLOODS:
* FBC + DIFF. WBC (NEUTROPHIL LEUCOCYTOSIS) * ESR, CRP * BLOOD CULTURES x3 (at peak of temp. ~ 60% are +ve) - 50:50 may culture bacteria * U+E = ILL, DEHYDRATED
IMAGING:
* X-RAY (normal in the first 10-14 days) - > 10-20 days may see early periosteal changes, the medulla may show lytic areas, may then see sequestrum (late osteonecrosis) + involucrum (late periosteal new bone) * USS (may see periosteal pus) * MRI
OTHER:
* ASPIRATION for pus (will aspirate if purulent matter is suspected) * ISOTOPE BONE SCAN * LABELLED WHITE CELL SCAN (white cells congregate at site of infection)
MICROBIOLOGICAL DIAGNOSIS:
* BLOOD CULTURES in HAEMATOGENOUS OM & SEPTIC ARTHRITIS = 5-6x * BONE BIOPSY * TISSUE/SWABS from up to 5 SITES ~ IMPLANT at DEBRIDEMENT in PROSTHETIC INFECTIONS * SINUS TRACT & SUPERFICIAL SWAB RESULTS may be MISLEADING (SKIN CONTAMINANTS may be found on superficial swabs - take swabs from DEEPER REGIONS of INFECTION to be more accurate)
Acute OM management
- SUPPORTIVE TREATMENT for PAIN + DEHYDRATION
- GENERAL CARE, ANALGESIA
- REST + SPLINTAGE
- ANTIBIOTICS = FLUCLOXACILLIN for 4-6 WEEKS either ORALLY/IV until sensitivity results come out
- ROUTE = IV/ORAL SWITCH - 7-10 days, depending on how bad the infection is & whether pt. still has swallowing mechanisms intact
- DURATION = 4-6 WEEKS - depends on response, ESR
- CHOICE = EMPIRICAL (FLUCLOXACILLIN + BenzylPen - more just fluclox now) while waiting for sensitivity results
• SURGERY:
• INDICATIONS - aspiration for pus for diagnosis + culture, abscess drainage, debridement of dead/infected/contaminated tissue, refractory to non-operative rx after 24 - 48hrs • TIMING, DRAINAGE, LAVAGE INFECTED JOINT REPLACEMENTS - ONE STAGE REVISION/TWO STAGE REVISION/ANTIBIOTICS ONLY
Chronic OM management
• LONG-TERM ANTIBIOTICS
* LOCAL = GENTAMICIN CEMENT/BEADS, COLLATAMP * SYSTEMIC = ORALLY/IV/HOME AB
- SURGERY = ERADICATE BONE INFECTION, may req. multiple operations
- PLASTICS = TREAT SOFT TISSUE PROBLEMS
- DEFORMITY CORRECTION
- MASSIVE RECONSTRUCTION
- AMPUTATION may be necessary
Acute OM complications
- SEPTICAEMIA, DEATH
- METASTATIC INFECTION
- PATHOLOGICAL FRACTURE = weakened bone
- SEPTIC ARTHRITIS
- ALTERED BONE GROWTH = near growth/epiphyseal plate
- CHRONIC OSTEOMYELITIS
Chronic OM complications
- CHRONICALLY DISCHARGING SINUS + FLARE-UPS
- ONGOING (METASTATIC) INFECTION (ABSCESSES)
- PATHOLOGICAL FRACTURE (as the bone will be weaker)
- GROWTH DISTURBANCE + DEFORMITIES (if near growth/epiphyseal plate)
- SQUAMOUS CELL CARCINOMA = V. RARE (0.07%), if the sinus changes
What is septic arthritis
INFECTION of JOINTS
Acute septic arthritis presentation in infants
• SEPTICAEMIA (JUST SICK) - OFTEN have MULTIPLE SITES of INFECTION
* IRRITABLE * RESISTANT TO MOVEMENT * ILL
Acute septic arthritis presentation in children
• ACUTE PAIN in SINGLE LARGE JOINT (superficial joints will be more obvious in swelling, deeper joints are more difficult as swelling may not be obvious & ∴ may take up to 30 days to diagnose)
* RELUCTANT TO MOVE JOINT AT ALL (any movement is not permitted - OM may permit some movement, bursitis - RoM is fine) * INCREASED TEMP. + PULSE * INCREASED TENDERNESS
Acute septic arthritis presentation in adults
- OFTEN involves SUPERFICIAL JOINT = KNEE, ANKLE, WRIST
- RARE in HEALTHY ADULT (but still poss.)
- May have delayed diagnosis
Acute septic arthritis presentation in adults
- OFTEN involves SUPERFICIAL JOINT = KNEE, ANKLE, WRIST
- RARE in HEALTHY ADULT (but still poss.)
- May have delayed diagnosis
Acute septic arthritis epidemiology
- IN ADULTS = INFECTED JOINT REPLACEMENT MOST COMMON CAUSE of SEPTIC ARTHRITIS
- RARE but DISASTROUS (death, amputation, removal of arthroplasty)
- PROSTHESIS CANNOT FIGHT OFF INFECTION LIKE HUMAN TISSUE - so BACTERIA ACCUMULATE + COLONISE PROSTHESIS + FORM BIOFILMS - V. DIFFICULT TO REMOVE
- CHANGING CAUSATIVE ORGANISMS = STAPH. AUREUS & STAPH. EPIDERMIDIS still MOST COMMON
Acute septic arthritis infection source/route
- HAEMATOGENOUS
- ERUPTION of BONE ABSCESS
- DIRECT INVASION = PENETRATING WOUND (could be iatrogenic i.e. joint injection), INTRA-ARTICULAR INJURY, ARTHROSCOPY
Acute septic arthritis micro-organisms
• COMMON:
* STAPH. AUREUS * HAEMOPHILUS INFLUENZAE * STREP. PYOGENES * E. COLI
Acute septic arthritis investigations/diagnosis
- FBC
- WBC
- ESR, CRP
- X-RAY
- USS
• ASPIRATION
Acute septic arthritis management
- AIM TO START TREATMENT BEFORE ARTICULAR CARTILAGE STARTS TO BE DAMAGED
- GENERAL SUPPORTIVE MEASURES
- ANTIBIOTICS = 3-4 WEEKS
- SURGICAL DRAINAGE & LAVAGE = EMERGENCY (remove pus asap); OPEN/ARTHROSCOPIC LAVAGE
- INFECTED JOINT REPLACEMENTS = ONE STAGE REVISION/TWO STAGE REVISION, ANTIBIOTICS
Acute septic arthritis complications
- MAY RECOVER COMPLETELY - IF CAUGHT EARLY ENOUGH TO AVOID CARTILAGE DESTRUCTION
- PARTIAL LOSS of ARTICULAR CARTILAGE & SUBSEQUENT OSTEOARTHRITIS
FIBROUS/BONY ANYLOSIS (JOINT FUSION) - fibrous if the cartilage fuses, bony if the cartilage is so damaged that only bone remains & fuses
TB bone + joint infection presentation
- INSIDIOUS ONSET & GENERAL ILL HEALTH
- CONTACT w/ TB
- PAIN (esp. at NIGHT), SWELLING, WGT. LOSS
- LOW GRADE PYREXIA
- JOINT SWELLING = THICKENED SYNOVIUM
- DECREASED ROM
- ANKYLOSIS = DESTROYS CARTILAGE
- DEFORMITY
SPINAL = LITTLE PAIN, PRESENT w/ ABSCESS/KYPHOSIS
TB bone + joint infection presentation
- INSIDIOUS ONSET & GENERAL ILL HEALTH
- CONTACT w/ TB
- PAIN (esp. at NIGHT), SWELLING, WGT. LOSS
- LOW GRADE PYREXIA
- JOINT SWELLING = THICKENED SYNOVIUM
- DECREASED ROM
- ANKYLOSIS = DESTROYS CARTILAGE
- DEFORMITY
SPINAL = LITTLE PAIN, PRESENT w/ ABSCESS/KYPHOSIS
TB bone + joint infection micro-organism
MYCOBACTERIUM TUBERCULOSIS
TB bone + joint infection micro-organism
MYCOBACTERIUM TUBERCULOSIS
TB bone + joint infection pathophysiology
- CLASSIFICATION:
- EXTRA-ARTICULAR (EPIPHYSEAL/BONES w/ HAEMODYNAMIC MARROW)
- INTRA-ARTICULAR (LARGE JOINTS)
- VERTEBRAL BODY = COMMONEST SITE
- MULTIPLE LESIONS in 1/3 of PT.
- PRIMARY COMPLEX (LUNG/GUT)
- SECONDARY SPREAD
- TUBERCULOUS GRANULOMA
• NUTRITION/OTHER DISEASE e.g. HIV, AIDS plays a role in host immunity
TB bone + joint infection investigations/diagnosis
DIAGNOSIS:
- LONG Hx
- SINGLE JOINT INVOLVED
- MARKED THICKENING of SYNOVIUM
- MARKED MUSCLE WASTING = STICK THIN THIGHS
- PERIARTICULAR OSTEOPOROSIS = MARKED
- FBC, ESR
- MANTOUX TEST
- SPUTUM/URINE CULTURE
- X-RAY = looking for SOFT TISSUE SWELLING, PERIARTICULAR OSTEOPAENIA, ARTICULAR SPACE NARROWING
- JOINT ASPIRATION & BIOPSY = TRY TO IDENTIFY via MICROSCOPY/CULTURE
- May see a change in histology
TB bone + joint infection management
- CHEMOTHERAPY
- INITIALLY: 8 WEEKS RIFAMPICIN, ISONIAZID, ETHAMBUTOL & THEN: 6-12 MONTHS RIFAMPICIN & ISONIAZID
- REST & SPLINTAGE
- OPERATIVE DRAINAGE rarely necessary
TB bone + joint infection DDx
- TRANSIENT SYNOVITIS
- MONOARTICULAR RHEUMATOID ARTHRITIS
- HAEMORRHAGIC ARTHRITIS
- PYOGENIC ARTHRITIS
- TUMOUR = more common
