Bone Problems Flashcards
(47 cards)
How does bacteria actually get into the bone?
Haematogenous spread
In osteomyelitis where exactly does the infection occur?
Bone + marrow
In children how does osteomyelitis occur?
Transient bacteraemia – >
seeding of metaphysis - usually at tibia/fibula
In adults how does osteomyelitis occur?
Open wound – >bacteraemia – > seed epiphysis
What is the most common site of infection in the bone? And why?
Metaphysis
Vascular supply is the best at metaphysis
therefore favours haematogenous spread
What is the most common bacteria cause of osteomyelitis?
Staph aureus
Are sexually active adults presents with osteomyelitis. What bacterial infection does he have?
Neisseria gonorrhoea
A patient with sickle-cell disease presents with osteomyelitis. What bacterial infection does he have?
Salmonella
Diabetic + IV drug user
who happens to wear rubber footwear and has a puncture in his foot
presents with osteomyelitis. What a bacterial infection does he have?
Pseudomonas
Patient presents with a cat/dog bite.
What bacterial infection does he have?
Apart from the obvious what else does he have?
Osteomyelitis
Cellulitis septic arthritis endocarditis meningitis
COSEM..
A patient with TB presents with osteomyelitis. It has affected his lumbar vertebrae. What does he have? And where does the spread come from?
Pots disease
Haematogenous spread from primary lung focus
What are the clinical features of osteomyelitis?
Bone pain, fever, leucocytosis,
Warmth, erythema, swelling
On x-ray what do is see for osteomyelitic infection?
Lytic focus
(Liquefactive necrosis -Sequestrum Brodies abscess)
surrounded by sclerosis – Involucrum
Treatment for osteomyelitis?
How do you diagnose it?
Surgery + antibiotics
Blood culture
Explain how we form that reactive bone that causes sclerosis?
Bacteria – > inflammatory exudate @marrow ->
increased intermedullary pressure
+
exudate into bone cortex – >
neutrophils enzymatically destroyed by bone – >
Rupture through periosteum->interrupt periosteal BF
sequestral/Devitalisation of bone - leave pieces – >
Chronic disease = reactive bone formation @periosteoma = involucrum
+
Brody’s abscess
– >From draining sinus tract formation @skin =
high risk of squamous CC + Sinus tract orifice
Where does avascular necrosis usually occur?
Scaphoid
Humeral
Femoral (Most common)
Talus
Explain how an old woman develops avascular necrosis in the femoral head?
Insufficiency of Retinacular arteries of the medial circumflex femoral artery
In avascular necrosis what is the necrosis due to?
Decreased blood flow – >ischaemic necrosis @bone
What are the causes of avascular necrosis?
ASEPTIC
Alcoholism
Sickle-cell disease – dactylitis =
vasoocclusive crisis @both hands and feet
Exo/endogenous corticosteroids – >fat embolus – >occlude microcirculation
Pancreatitis
Trauma – >decreased blood flow
Idiopathic = Legg Calvé Perthe disease
Caisson disease
Explain Legg Calvé perthes disease.
AAN of ossification centres – epiphysis
@ kids 3–10 years
of femoral head – knee pain/limp
Explain Caisson disease.
Gas embolus – nitrogen – >
precipitate out of blood – > lodge in bone – > AAN
What is the complication of avascular aseptic necrosis
AAN under joint – >increased risk of joint damage – >osteoarthritis
AAN under joint – >fracture
Explain the difference between a peritrochanteric and subcapsular fracture.
PeriTrochanteric fracture = extracapsular = no blood supply to femoral head – > no AAN
Sub capsular fracture = disrupts blood supply –> retinacular art. of medial circumflex fem. artery – > AAN
Treatment for avascular aseptic necrosis
Joint replacement
Core decompression
Bone graft/BISPHOSPHONATES
