Rheumatology Flashcards
What is a rheumatological condition that needs to be treated immediately?
Septic arthritis
What is septic arthritis?
Joint infection caused by bacteria or a virus that spreads to the fluid surrounding the joint
What is the most common organism that causes septic arthritis?
Staphylococcus aureus
What is the most common organism that causes septic arthritis in young sexually active individuals?
Gonococcus
What other organisms can cause septic arthritis?
1) Streptococcus
2) Gram negative bacilli
What are risk factors for septic arthritis?
1) Pre-existing joint disease e.g. RA
2) CKD
3) Immunosuppression
4) Prosthetic joints
What are the clinical features of septic arthritis?
1) Acutely inflamed, tender, swollen, erythematous, hot joint - most commonly knee
2) Reduced range of movement
3) Systemically unwell
What is the key diagnostic investigation for septic arthritis?
Joint aspiration for MC&S (send synovial fluid for urgent gram stain and culture) - before starting abx
What does the fluid look like after joint aspiration of a septic arthritis joint?
Turbid, yellow, resembling pus
What other investigations would you do for septic arthritis?
1) Blood tests - esp. FBC and CRP
2) Blood cultures
3) Joint x-ray - may be normal or may suggest bone involvement
What will blood tests show in septic arthritis?
High WCC, high ESR/CRP
How do you manage septic arthritis?
1) IV antibiotics according to local guidelines - empirical until sensitivities are known
2) Consider joint washout under GA
3) Splint for < 48h and analgesia
4) Physiotherapy after acute infection resolves
What are potential complications of septic arthritis?
1) Osteomyelitis
2) Arthritis
3) Ankylosis fusion
What imaging would be done if there is concern of osteomyelitis?
MRI
When may surgical washout be necessary after joint aspiration in septic arthritis?
If there is still an effusion in the knee joint despite serial joint aspirations esp. if there is a prosthetic joint
Why is ultrasound of the knee joint not essential as an investigation of septic arthritis?
Bc the swelling and effusion of the knee joint can be determined on examination
What is the role of ultrasound imaging in septic arthritis?
When ultrasound guidance may be needed to aspirate small joints
Bilateral, proximal muscle weakness that develops over weeks-months?
Polymyositis
What is the main feature of polymyositis?
Variable muscle weakness - bilateral, proximal (hip and shoulder girdle) muscle weakness, developing over weeks to months
What are additional symptoms in polymyositis that may be present in approx ⅓ of patients?
1) Muscle pain (myalgia)
2) Muscle tenderness
What two characteristics are preserved until very late in polymyositis?
1) Muscle bulk
2) Reflexes