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Musculoskeletal System > Bone + Soft Tissue Infections > Flashcards

Bone + Soft Tissue Infections Flashcards

1
Q

What is osteomyelitis

A

INFECTION of BONE - specific/non-specific

non-specific most common

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2
Q

Acute OM presentation in infants

A

• 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

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3
Q

Acute OM presentation in children

A
  • 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
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4
Q

Acute OM presentation in adults

A
  • 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
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5
Q

Chronic OM presentation

A

Involves REPEATED BREAKDOWN of “HEALED” WOUNDS = LOTS of SINUSES

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6
Q

Acute OM epidemiology

A
  • MOSTLY CHILDREN - DIFF. AGES
  • BOYS > GIRLS
  • Hx of TRAUMA - MINOR
  • OTHER DISEASE:
    • DM
    • RHEMATIC ARTHRITIS
    • IMMUNE COMPROMISE
    • LONG-TERM STEROID TREATMENT
    • SICKLE CELL
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7
Q

Acute OM infection source/route

A
  • 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

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8
Q

Chronic OM infection source/route

A
  • 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.
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9
Q

Acute OM micro-organisms

A

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

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10
Q

Chronic OM micro-organisms

A

often mixed infection - usually same organism/s each flare up

mainly = s. aureus, e. coli, strep. pyogenes, proteus

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11
Q

Acute OM pathophysiology

A

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)
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12
Q

Chronic OM pathophysiology

A
  1. CAVITIES, poss. SINUS/ES
  2. DEAD BONE (RETIANED SEQUESTRA)
  3. INVOLUCRUM
  4. HISTOLOGICAL PICTURE is one of CHRONIC INFLAMMATION
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13
Q

Acute OM investigations/diagnosis

A

• 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 &amp; SEPTIC ARTHRITIS = 5-6x
* BONE BIOPSY
* TISSUE/SWABS from up to 5 SITES ~ IMPLANT at DEBRIDEMENT in PROSTHETIC INFECTIONS
* SINUS TRACT &amp; 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)
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14
Q

Acute OM management

A
  • 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
    • Antibiotics are chosen according to their: SPECTRUM of ACTIVITY, PENETRATION to BONE, SAFETY for LONG-TERM ADMINISTRATIONANTIBIOTIC FAILURE: due to drug resistance, bacterial persistence, poor host defences, poor drug absorption, drug inactivation by host flora, poor tissue penetration

• 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
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15
Q

Chronic OM management

A

• 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
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16
Q

Acute OM complications

A
  • SEPTICAEMIA, DEATH
  • METASTATIC INFECTION
  • PATHOLOGICAL FRACTURE = weakened bone
  • SEPTIC ARTHRITIS
  • ALTERED BONE GROWTH = near growth/epiphyseal plate
  • CHRONIC OSTEOMYELITIS
17
Q

Chronic OM complications

A
  • 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
18
Q

What is septic arthritis

A

INFECTION of JOINTS

19
Q

Acute septic arthritis presentation in infants

A

• SEPTICAEMIA (JUST SICK) - OFTEN have MULTIPLE SITES of INFECTION

* IRRITABLE
* RESISTANT TO MOVEMENT
* ILL
20
Q

Acute septic arthritis presentation in children

A

• 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
21
Q

Acute septic arthritis presentation in adults

A
  • OFTEN involves SUPERFICIAL JOINT = KNEE, ANKLE, WRIST
  • RARE in HEALTHY ADULT (but still poss.)
  • May have delayed diagnosis
22
Q

Acute septic arthritis presentation in adults

A
  • OFTEN involves SUPERFICIAL JOINT = KNEE, ANKLE, WRIST
  • RARE in HEALTHY ADULT (but still poss.)
  • May have delayed diagnosis
23
Q

Acute septic arthritis epidemiology

A
  • 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
24
Q

Acute septic arthritis infection source/route

A
  • HAEMATOGENOUS
  • ERUPTION of BONE ABSCESS
  • DIRECT INVASION = PENETRATING WOUND (could be iatrogenic i.e. joint injection), INTRA-ARTICULAR INJURY, ARTHROSCOPY
25
Q

Acute septic arthritis micro-organisms

A

• COMMON:

* STAPH. AUREUS
* HAEMOPHILUS INFLUENZAE
* STREP. PYOGENES
* E. COLI
26
Q

Acute septic arthritis investigations/diagnosis

A
  • FBC
  • WBC
  • ESR, CRP
  • X-RAY
  • USS

• ASPIRATION

27
Q

Acute septic arthritis management

A
  • 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
28
Q

Acute septic arthritis complications

A
  • 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

29
Q

TB bone + joint infection presentation

A
  • 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

30
Q

TB bone + joint infection presentation

A
  • 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

31
Q

TB bone + joint infection micro-organism

A

MYCOBACTERIUM TUBERCULOSIS

32
Q

TB bone + joint infection micro-organism

A

MYCOBACTERIUM TUBERCULOSIS

33
Q

TB bone + joint infection pathophysiology

A
  • 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

34
Q

TB bone + joint infection investigations/diagnosis

A

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
35
Q

TB bone + joint infection management

A
  • CHEMOTHERAPY
    • INITIALLY: 8 WEEKS RIFAMPICIN, ISONIAZID, ETHAMBUTOL & THEN: 6-12 MONTHS RIFAMPICIN & ISONIAZID
  • REST & SPLINTAGE
  • OPERATIVE DRAINAGE rarely necessary
36
Q

TB bone + joint infection DDx

A
  • TRANSIENT SYNOVITIS
  • MONOARTICULAR RHEUMATOID ARTHRITIS
  • HAEMORRHAGIC ARTHRITIS
  • PYOGENIC ARTHRITIS
  • TUMOUR = more common

Musculoskeletal System (16 decks)

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