Septic Arthritis and Rheumatic Fever

Question 1

Differnetial diagnosis for hot swollen knee joint/ joints

Answer 1

Septic arthritis, rheumatic fever, other reactive arthritis, trauma

Question 2

Gram stain revision

Answer 2

Gram +: Streptococci: alpha haemolytic: pneumoniae, Beta: pyogenes; staphyococci
Gram -: Nesseria meninigitidis

Gram + bacillus: Clostridium, listeria
Gram - bacillus: Haemophillus influenzae, enteric pathogens e.coli, salmonella

Question 3

GAS disease burden

Answer 3

Acute pyogenic/suppurative: tonsilitis, pharyngitis, scarlet fever, septic arthritis
Non suppurative/inflammatory sequelae: Acute rheumatic fever/RHD, post streptococcal glomerulonephritis

Question 4

Septic arthritis

note most common cause staph then strep

Answer 4

• Occurs often in childhood
• occurs with fever and malaise
• swelling, erythema
• Joint held in position that maximise joint capsule volume: Flexed knee, flexed abducted ext rotated hip
• Joint aspirate
• Must be diagnosed quick to prevent any growth plate disruption

Question 5

Septic arthritis management

Answer 5

Joint washouts
IV antibiotics
Then oral course, total a few weeks

Question 6

ARF

Answer 6

Following throat infection GAS. Occurs several weeks before
Generalised inflammation: heart, joints, skin
Can lead to RHD (damage to valves)

Question 7

Jones criteria

Answer 7

Used to diagnose rheumatic heart disease. 2 Major or 1 major and 2 minor criteria
Major: Carditis, polyarthritis (asymmetircal and migratory), sydenhams chorea, erythema marginatum
Minor: fever, polyarthrlagia, raised CRP or ESR, prolonged PR on ECG

Question 8

Arthritis vs arthralgia

Answer 8

Arthritis: Limitation of movement, hot joint and pain or tender to palpate
Arthralgia: pain only

Question 9

How does RF occur

Answer 9

Autoimmune mechanism where antibodies created against strep interact with similar host proteins. e.g M protein and cardiac myosin

Question 10

Importance of strep antibody titres

Answer 10

Neede to confirm strep and ARF.
Use ASO (antistreptolysin) and anti-DNAse B titres.

Question 11

Preventing RF and managing

Answer 11

managing: best rest, monitor systemic inflammation (CRP)IM penicillin every 4 weeks for next ten years

Preventing: Penicillin

Question 12

Septic arthritis vs RF

Answer 12

Septic arthritis: Any age group, acute active infection, arthritis due to bacteria in joint, staph or strep, treat with cleaning and antibiotic (aqueous penicillin G, then IM benzathine penicillin G)

RF: school age 5-15, AI, multisystem, penicillin used long term