Septic Arthritis

Question 1

Septic Arthritis

Answer 1

Overview

• most common organism overall is Staphylococcus aureus
• in young adults who are sexually active Neisseria gonorrhoeae should also be considered

Question 2

Septic Arthritis - Mx

Answer 2

Management
- synovial fluid should be obtained before starting treatment
- intravenous antibiotics which cover Gram-positive cocci are indicated. The BNF currently recommends flucloxacillin or clindamycin if penicillin allergic
antibiotic treatment is normally be given for several weeks (BNF states 6-12 weeks)
- needle aspiration should be used to decompress the joint
- arthroscopic lavage may be required

Question 3

Septic Arthritis - Example Question

Answer 3

A 23 year old comes in with a painful right knee. He denies any specific trauma. He has no past medical history. On examination, he has a red and warm knee with a moderate effusion. His observations are respiratory rate of 24/min, blood pressure 120/72 mmHg, temperature 37.8ºC. His knee is aspirated which is cloudy in appearance. Laboratory testing shows calcium pyrophosphate crystals and gram stain is awaited. What is the appropriate treatment plan?

	> Admit for intravenous antibiotics
	Home with analgesia
	Admit awaiting cultures
	Check ferritin
	Intra-articular depo-medrone

Septic arthritis has not been ruled out until there are no organisms seen. The patient should be treated with intravenous antibiotics as soon as the aspirate has been taken and only be discharged once it is confirmed that they do not have septic arthritis.

Although calcium pyrophosphate crystals are most associated with pseudo gout they do not rule out septic arthritis. The ferritin would be raised in septic arthritis so using it as a screen for haemochromatosis would not be advisable in this setting.