Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

E - MSK > Bone and Tissue Infections > Flashcards

Bone and Tissue Infections Flashcards

1
Q

Common background for acute osteomyelitis

A

Children - boys
History of trauma
Other long term disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Source of infection for acute OM

A

Haematogenous spread
Local spread from contiguous site of infection (open fracture, bone surgery, joint replacement)
Secondary to vascular insufficiency
Infants = infected umbilical cord
Children = boils, tonsillitis, skin abrasions
Adults = UTI, arterial line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Common organisms of acute OM

A 
Infants - E. coli 
Older - staph aureus
Prostheses - coagulase -ve strep
Infectious arthritis - strep pyogenes 
Secondary to penetrating foot injury - pseudomonas aeruginosa 
Sickle cell disease - salmonella
Butchers - Brucella 
Candida - HIV, long term Abx, malignancy
Vertebral OM - s. aureus, TB 
STD - gonococcus
  • Group B strep
  • Strep pyogenes
  • Haemophilus influenzae
  • Proteus / Klebsiella
  • Mycobacteria tuberculosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Pathology of acute OM - order of events

A
  1. Starts at metaphysis (role of trauma)
  2. Vascular stasis - venous congestion + arterial thrombosis
  3. Acute inflammation causes increased pressure
  4. Pus forms
  5. Release of pressure
  6. Necrosis of bone
  7. New bone formation
  8. Resolution or not - chronic OM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Clinical features of acute OM in infants

A 
Failure to thrive 
Drowsy 
Irritable 
Metaphyseal tenderness + swelling 
Positional change 
Decreased ROM esp knee
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Clinical features of acute OM in children

A 
Severe pain 
Reluctant pain 
Fever + tachycardia 
Malaise 
Toxaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Clinical features of acute OM in adults

A

Primary OM common in thoracolumbar spine

  • Back ache
  • UTI Hx
  • Elderly, diabetic

Secondary OM more common

  • open fracture, surgery
  • mixture of organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Diagnosis of acute OM

A 
H&E
FBC + WCC (neutrophil leucocytosis)
ESR, CRP rise
Blood cultures x3 (+ve in60%)
U&Es - dehydrated 
X-Ray (normal in first 10-14 days)
MRI - preferred 
Isotope bone scan sometimes required i.e. in presence of prostheses)

USS
Aspiration
Labelled white cell scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Differential diagnosis of acute OM

A 
Acute septic arthritis 
Acute inflammatory arthritis 
Trauma 
Transient synovitis 
Soft Tissue Infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does x-ray of acute OM show

A

Good disc = tumour (bad)
Bad disc = infection (good)

Nothing for 10-14 days
Then haziness + loss of density
Then subperiosteal reaction
Later see sequestrum (late osteonecrosis) and Involucrum (late periosteal new bone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Microbiological diagnosis

A

Blood cultures
Bone biopsy
Tissue swabs from up to 5 sites around implant in prosthetic infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Treatment of acute OM

A

Supportive for pain and dehydration
Rest and splint age

Abx (High dose IV 6 weeks)

  • empirical flucloxacillin and Benzylpenicillin while waiting for organism and sensitivities)
  • switch to oral 7-10 days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Indications for surgery in acute OM

A

Aspiration of pus for diagnosis and culture
Drain abscess and remove sequestra
Debridement of dead or infected or contaminated tissue
Refractory to non-surgical treatment >24-48hrs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Complications of acute OM

A 
Septicaemia 
Metastatic infection 
Pathological fracture
Septic Arthritis 
Altered bone growth 
Chronic OM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Common presentation of chronic OM

A

Follow acute OM
Following operation
Following open fracture
Long-term conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Common organism in chronic OM

A

Often mixed

- s aureus, E. coli, strep pyogenes, proteus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Treatment of chronic OM

A

Radical excision of sequestra
Skeletal stabilisation
Dead-space management - reconstruction
Abx - local gentamicin cement, beads or systemic oral / IV

18
Q

Complications of chronic OM

A

Amyloid
Squamous cell carcinoma development in sinus track
Pathological fracture
Ongoing infection

19
Q

Risk factors for OM

A 
Diabetes
Vascular disease
Impaired immunity 
Sickle cell disease
Surgical prostheses
Open fractures
20
Q

Patterns of infection of OM

A

In adults, cancellous bone is typically affected.
In children, vascular bone is commonly affected (i.e. long bone metaphases - esp. distal femur, upper tibia)

This leads to cortex erosion with holes (cloacae). The pus lifts up the periosteum causing death of the original bone (sequestrum). Continued bone formation by the elevated periosteum forms an involucrum. Pus may discharge into joint spaces or via sinuses to the skin.

21
Q

Route of infection in acute septic arthritis

A

Direct invasion - penetrating wound, injury
Eruption of bone abscess
Haematogenous
Metaphysial Septic Focus

22
Q

Organisms in acute septic arthritis

A

Staph aureus
Haem influenzae
Strep pyogenes
E. coli

23
Q

Pathology of ASA

A

acute synovitis and purulent joint effusion causing destruction of the articular cartilage

24
Q

Sequelae of ASA

A

Complete recovery
OR partial loss of the articular cartilage and OA
OR fibrous or bony ankylosis

25
Presentation of ASA in neonate
irritability resistant to movement ill
26
Presentation of ASA in child
Acute pain in single large joint Reluctant to move Increased temp and pulse and tenderness
27
Presentation of ASA in Adult
Common in superficial joints (knee, ankle, wrist) | Rare in healthy adult
28
Investigations of ASA
``` FBC, WBC, ESR, CRP Blood cultures X-ray USS Aspiration ```
29
Most common cause of ASA in adult
Infected joint replacement
30
Ddx of ASA
``` Acute OM Trauma Irrritable joint Haemophilia Rheumatic fever Gout Gaucher's disease ```
31
Treatment of ASA
Abx 4 weeks | Surgical drainage and lavage
32
Classification of bone TB
``` Extra-articular - epiphyseal / bones with haemodynamic marrow Intra-articular - large joints Vertebral body (Pott's disease) ```
33
How does TB spread to bones
Haematogenous or via nearby nodes
34
Clinical features of bone TB
``` Pain esp at night Swelling Cold abscess formation +/- joint formation Joint pain on movement Decreased ROM Muscle wasting Weight loss Malaise, fever, lethargy Insidious onset ```
35
Pathology of bone TB
Primary complex (in lung or gut). Then secondary spread causing a tuberculous granuloma
36
How does spinal TB present
Little pain Abscess Kyphosis
37
Diagnosis of bone TB
``` Long history Involvement of single joint Marked thickening of synovium Marked muscle wasting Periarticular osteoporosis ```
38
Investigations for bone TB
``` FBC ESR - elevated Matoux test = +ve Sputum / Urine culture X-ray MRI Joint aspiration and biopsy ```
39
Findings on x-ray in bone TB
Periarticular osteopenia Articular space narrowing Soft tissue swelling (MRI)
40
findings on joint aspiration and biopsy in bone TB
AAFB in 20% | Culture +ve in 50%
41
Ddx for bone TB
``` Transient synovitis Monoarticular RA Haemorrhagic / Pyogenic arthritis Malignancy Gout ```
42
Treatment for bone TB
Chemotherapy - Rifampicin, Isoniazid, Ethambutol for 8 weeks - Rifampicin, Isoniazid for 6-12 months Rest and splintage Operative drainage rarely needed

E - MSK (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions