General 2

Question 1

what is compartment syndrome and where are the most common places to get it

Answer 1

defined as a critical increase in pressure within a confined compartmental space - fascial compartments are closed and cannot be distended, consequently any fluid that is deposited therein will cause an increase in the intra-compartmental pressure

most commonly affects legs, thighs, forearms, foot, hand and buttocks

Question 2

what are some of the most common injuries that cause compartment syndrome

Answer 2

following high energy trauma, crush injuries or fractures that cause vascular injury

other causes are; burns, DVT, tight casts or splints

Question 3

pathophysiology behind compartment syndrome

Answer 3

fascial compartments are closed and cannot be distended, consequently any fluid that is deposited therein will cause an increase in the intra-compartmental pressure

as this pressure increases, the veins become compressed, this increases the hydrostatic pressure within them, causing fluid to move down its conc gradient and into the compartment, further increasing the intra-compartmental pressure

then the traversing nerves are compressed - this causes a sensory and motor deficit. paraesthesia is therefore a common symptom

lastly as the intra-compartmental pressure reaches the diastolic blood pressure, the arterial flow will be compromised, leading to ischaemia - this is a late sign of missed compartment syndrome

Question 4

clinical features of compartment syndrome

Answer 4

severe pain disproportionate to the injury - made worse by passively stretching the muscles

paraesthesia distally is a common symptom

affected compartment may feel tense compared to the other side but will not generally be swollen

Question 5

management of compartment syndrome

Answer 5

early recognition and surgical treatment via urgent fasciotomies is the most important part

prior to definitive management; remove all dressing, opioid analgesia, keep limb at a neutral level with the patient

Question 6

what should you monitor closely after compartment syndrome

Answer 6

renal function due to the potential of rhabdomyolysis and reperfusion injury

Question 7

what is septic arthritis and what is the main causative organism

Answer 7

infection of a joint - can be both native and prosthetic joints

most common causative organism is S. aureus

Question 8

what are the different ways that bacteria can seed to a joint

Answer 8

bacteraemia - e.g. recent cellulitis, UTI, chest infection

direct inoculation

spreading from adjacent osteomyelitis

Question 9

risk factors for septic arthritis

Answer 9

age >80yrs

pre-existing joint disease e.g. RA

diabetes or any other immunosuppression

chronic renal failure

hip or knee joint prosthesis

IV drug use

Question 10

clinical features of septic arthritis

Answer 10

single, swollen joint causing severe pain

pyrexia present in around 60% of individuals

red, warm, swollen, causing pain on active and passive movements

Question 11

investigations into septic arthritis

Answer 11

routine bloods + ESR + serum urate

blood cultures (before giving antibiotics)

joint aspiration - sent for gram stains, leucocyte count, polarising microscopy and fluid culture (send joint aspiration before giving antibiotics)

Question 12

management of septic arthritis

Answer 12

empirical antibiotic treatment - often for 4-6 weeks

infected joints also require surgical irrigation and debridement

Question 13

what is osteomyelitis and how can it be spread

Answer 13

infection of the bone

caused by haematogenous spread, direct inoculation of microorganisms into the bone e.g. open fracture or penetrating injury, or direct spread from nearby infection

Question 14

what is the most common causative organism in osteomyelitis

Answer 14

S. aureus

Question 15

pathophysiology of osteomyelitis

Answer 15

once bacteria enter the bone tissue, they express adhesins to bind to the host tissue proteins and produce a polysaccharide extracellular matrix

through this the pathogens are able to propagate, spread and seed further in tissue

Question 16

risk factors for osteomyelitis

Answer 16

diabetes

immunosuppression e.g. long term steroid treatment or AIDS

alcohol excess

IV drug use

Question 17

what should you keep as a differential in a diabetic patient with a deep or chronic foot infection

Answer 17

osteomyelitis - soft tissue infection can increase the risk of it

Question 18

clinical features of osteomyelitis

Answer 18

severe pain in affected area

associated low grade fever

pain is constant and is usually worse at night (RED FLAG)

on examination the site will be tender with overlying swelling and erythema

Question 19

what is potts disease

Answer 19

infection of the vertebral body and intervertebral disc by mycobacterium tuberculosis

Question 20

investigations into osteomyelitis

Answer 20

routine bloods + ESR

blood cultures

gold standard is from culture from bone biopsy at debridement

MRI can also make a definitive diagnosis

Question 21

complications of osteomyelitis

Answer 21

overwhelming sepsis and mortality

children can develop growth disturbances due to premature physeal closure

chronic osteomyelitis requiring extensive long term antibiotic therapy and complex staged reconstruction with prolonged rehabilitation

Question 22

what are primary benign and malignant bone forming tumours called

Answer 22

Benign; Osteoma, osteoid osteoma and osteoblastoma

malignant; osteosarcoma

Question 23

what are primary benign and malignant cartilage forming bone tumours called

Answer 23

Benign; chondromas, osteochondromas, chondroblastoma

malignant; chondrosarcomas

Question 24

what are primary benign and malignant fibrous tissue bone tumours called

Answer 24

benign; fibromas, fibromatosis

malignant; fibrosarcoma

Question 25

what are the different types of bone marrow tumours

Answer 25

Ewings tumour

myeloma

Question 26

what are some types of malignant primary bone tumours

Answer 26

Osteosarcoma

Chondrosarcoma

Myeloma

Fibrosarcoma

Question 27

what is the most common cause of bone cancer

Answer 27

metastatic spread

primary sites being from the renal, thyroid, lung, prostate and breast

Question 28

where is the most common site for metastatic bone cancer

Answer 28

spine

Question 29

risk factors for bone cancer

Answer 29

genetic association

previous exposure to radiation and alkylating agents in chemo

benign bone conditions

Question 30

clinical features of bone cancer

Answer 30

constant severe bone pain - often worse at night (RED FLAG)

palpable mass if tumour is large enough

presentation with fracture without a history of trauma (pathological fracture)

Question 31

most common types of benign primary bone tumours

Answer 31

Osteoid Osteoma

Osteochondroma

Chondroma

Giant cell tumour

Question 32

what is an osteoid osteoma

Answer 32

benign primary bone tumour arising from osteoblasts, often around the second decade of life (10-20yrs)

usual presentation with localised progressive bone pain worse at night

Question 33

what are osteochondromas

Answer 33

benign bony tumour forming as an outgrowth from the metaphysis of long bones

they are covered with a cartilaginous cap

usually asymptomatic

Question 34

What are Chondromas

Answer 34

benign bony tumour arising from chondroblasts

most commonly affect long bones of the hands, femur and humerus

mostly asymptomatic however can present with pathological fracture

Question 35

what is the most common malignant primary bone tumour

Answer 35

osteosarcomas

Question 36

where are osteosarcomas most commonly found

Answer 36

metaphysis of the distal femur or proximal tibia

Question 37

what will plain film radiographs show in someone with osteosarcoma

Answer 37

medullary and cortical bone destruction - grey/blackened area within the bone

Question 38

what is the management of osteosarcomas

Answer 38

tissue biopsy required for diagnosis

warrants aggressive resection with systemic chemo

Question 39

what are ewing sarcomas

Answer 39

paediatric malignancy arising from primitive poorly differentiated neuroectodermal cells

shows as lytic lesion on plain film radiographs

Question 40

what are chondrosarcomas

Answer 40

malignant tumours of the cartilage

Question 41

difference between benign and malignant bone tumours on plain film radiographs

Answer 41

benign; sharp and well defined, lacking soft tissue involvement and no cortical destruction

malignant; poorly defined with rough borders, involving soft tissues and have cortical destruction

Question 42

management of bone tumours

Answer 42

depends on patient factors and disease factors

however in general, benign tumours are managed with observation and surveillance whereas malignant tumours are managed with surgery

Question 43

what is more common; primary or secondary (metastatic) bone tumours

Answer 43

secondary

Question 44

what are the most common tumours that spread to the bone

Answer 44

primary sites being from the renal, thyroid, lung, prostate and breast

Question 45

in IV drug users what organism is the most common cause of osteomyelitis

Answer 45

P. auruginosa