Arthritis
Bone infection organisms and sickle cell
Bacterial causes and predisposing disease for bone and joint infection
9 questions
2 source pages
2 images
Images appear with the first question taken from each source page — tap a question to open it.
Q1List the structures of a bacterium.📷▸
- Cell wall, cell membrane
- Pili, flagella
- Plasmid, nucleoid, ribosome
Q2What is the mechanism of MRSA resistance to beta-lactams?▸
- MRSA thrives despite penicillin-like (beta-lactam) antibiotics
- Beta-lactams normally prevent bacterial growth by inhibiting cell wall synthesis - inactivating transpeptidases
- Resistance gene mecA, which encodes the Penicillin binding Protein 2 alpha, a tanspeptidase for cell wall synthesis, but has a LOW affinity for β-lactam to bind to; this protein is also known as PBP2a
Q3When is MRSA classified as community-acquired?▸
- Picked up within 48 hours of admission
Q4What are the implications of community-acquired MRSA?▸
- Contains the PVL locus -> more severe soft tissue infection
- Causes neutrophil lysis
Q5How is MRSA decolonised?▸
- Mupirocin 2% applied to the anterior nares 3 times/day for 5 days
- Chlorhexidine 4% shampoo and skin cleanser for 5 days
- Daily change of sheets and clothes
Q6What is sickle cell disease and how is it inherited?📷▸
- A haemoglobinopathy producing HbS
- Autosomal codominant inheritance (page wording: 'codorminant')
Q7Describe the pathophysiology of sickling in sickle cell disease.▸
- Low oxygen tension -> RBC sickling
- Cell membrane damaged -> decreased elasticity -> cannot 'deform' when passing through vessels
- -> occlusion/ischaemia
Q8How is sickle cell disease diagnosed and managed?▸
- Dx: haemoglobin electrophoresis
- Prevent infection: vaccination/antibiotics
- Prevent stress: high fluid intake
- Folic acid, pain control, hydroxyurea
- Bone marrow transplant
Q9What are the orthopaedic implications of sickle cell disease?▸
- NO TOURNIQUET
- Osteomyelitis: salmonella (spleen damage, encapsulated organism)
- AVN
- Dactylitis
- Shorter life expectancy in general