General 2 Flashcards
what is compartment syndrome and where are the most common places to get it
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
what are some of the most common injuries that cause compartment syndrome
following high energy trauma, crush injuries or fractures that cause vascular injury
other causes are; burns, DVT, tight casts or splints
pathophysiology behind compartment syndrome
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
clinical features of compartment syndrome
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
management of compartment syndrome
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
what should you monitor closely after compartment syndrome
renal function due to the potential of rhabdomyolysis and reperfusion injury
what is septic arthritis and what is the main causative organism
infection of a joint - can be both native and prosthetic joints
most common causative organism is S. aureus
what are the different ways that bacteria can seed to a joint
bacteraemia - e.g. recent cellulitis, UTI, chest infection
direct inoculation
spreading from adjacent osteomyelitis
risk factors for septic arthritis
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
clinical features of septic arthritis
single, swollen joint causing severe pain
pyrexia present in around 60% of individuals
red, warm, swollen, causing pain on active and passive movements
investigations into septic arthritis
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)
management of septic arthritis
empirical antibiotic treatment - often for 4-6 weeks
infected joints also require surgical irrigation and debridement
what is osteomyelitis and how can it be spread
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
what is the most common causative organism in osteomyelitis
S. aureus
pathophysiology of osteomyelitis
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
risk factors for osteomyelitis
diabetes
immunosuppression e.g. long term steroid treatment or AIDS
alcohol excess
IV drug use
what should you keep as a differential in a diabetic patient with a deep or chronic foot infection
osteomyelitis - soft tissue infection can increase the risk of it
clinical features of osteomyelitis
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
what is potts disease
infection of the vertebral body and intervertebral disc by mycobacterium tuberculosis
investigations into osteomyelitis
routine bloods + ESR
blood cultures
gold standard is from culture from bone biopsy at debridement
MRI can also make a definitive diagnosis
complications of osteomyelitis
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
what are primary benign and malignant bone forming tumours called
Benign; Osteoma, osteoid osteoma and osteoblastoma
malignant; osteosarcoma
what are primary benign and malignant cartilage forming bone tumours called
Benign; chondromas, osteochondromas, chondroblastoma
malignant; chondrosarcomas
what are primary benign and malignant fibrous tissue bone tumours called
benign; fibromas, fibromatosis
malignant; fibrosarcoma
what are the different types of bone marrow tumours
Ewings tumour
myeloma
what are some types of malignant primary bone tumours
Osteosarcoma
Chondrosarcoma
Myeloma
Fibrosarcoma
what is the most common cause of bone cancer
metastatic spread
primary sites being from the renal, thyroid, lung, prostate and breast
where is the most common site for metastatic bone cancer
spine
risk factors for bone cancer
genetic association
previous exposure to radiation and alkylating agents in chemo
benign bone conditions
clinical features of bone cancer
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)
most common types of benign primary bone tumours
Osteoid Osteoma
Osteochondroma
Chondroma
Giant cell tumour
what is an osteoid osteoma
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
what are osteochondromas
benign bony tumour forming as an outgrowth from the metaphysis of long bones
they are covered with a cartilaginous cap
usually asymptomatic
What are Chondromas
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
what is the most common malignant primary bone tumour
osteosarcomas
where are osteosarcomas most commonly found
metaphysis of the distal femur or proximal tibia
what will plain film radiographs show in someone with osteosarcoma
medullary and cortical bone destruction - grey/blackened area within the bone
what is the management of osteosarcomas
tissue biopsy required for diagnosis
warrants aggressive resection with systemic chemo
what are ewing sarcomas
paediatric malignancy arising from primitive poorly differentiated neuroectodermal cells
shows as lytic lesion on plain film radiographs
what are chondrosarcomas
malignant tumours of the cartilage
difference between benign and malignant bone tumours on plain film radiographs
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
management of bone tumours
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
what is more common; primary or secondary (metastatic) bone tumours
secondary
what are the most common tumours that spread to the bone
primary sites being from the renal, thyroid, lung, prostate and breast
in IV drug users what organism is the most common cause of osteomyelitis
P. auruginosa
