Septic Arthritis Flashcards
Septic arthritis is when there is inflammation of a joint that is caused by a microorganism. It can be very dangerous and destroy a joint in <24h. For this reason it is classed as an orthopaedic emergancy. What is the most common microorgaism that leads to septic arthritis?
1 - Klebseilla
2 - Escherichia coli
3 - Staphylococcus aureus
4 - Clostridium difficile
3 - Staphylococcus aureus
- this is because this bacteris resides on the skin and is forced into the joint or tissues
- can also be caused by viruses or fungi
Which joint is most commonly affected in septic arthritis?
1 - vertebral
2 - knee
3 - shoulder
4 - hip
2 - knee
- 50% of cases affect the knee
- in children knee and hip are affected
Does septic arthritis only affect synovial joints?
- no
- it can affect any joint including fibrous, cartilaginous, and synovial joints
What is the incidence (number of new cases over a specificed time) of septic arthritis?
1 - 1-2/100,00 per year
2 - 10-20/100,000 per year
3 - 100-200/100,000 per year
4 - >1000/100,000 per year
1 - 1-2/100,00 per year
Does septic arthritis affect older or younger patients?
- both
- biomodal meaning it can affect <2 up to >60 y/o
All of the following are risk factors for septic arthritis, EXCEPTY which one?
1 - age <20 years
2 - pre existing joint disease (RA especially)
3 - diabetes
4 - immunocomprimised
5 - CKD
6 - recent joint surgery
7 - prosteic joint
8 - IV drug use
9 - recent infection (endocarditis or bacteraemia)
1 - age <20 years
- age is a risk factor, but generally affects those >80 y/o
All of the following are several ways in which joints can become infected causing septic arthritis, what is the most common way the causative agent is spread?
1 - haematogenous
2 - penetrating wound
3 - post surgery
4 - diabetci foot infeciton
1 - haematogenous
- can be causes by a penetrating wound
What is primarily destroyed within joints by the causative agent during an attack of septic arthritis?
1 - synovial fluid
2 - blood vessels
3 - inner synovial membrane
4 - articular cartilage
4 - articular cartilage
- can be destroyed within 8 hours
If not treated aggressivley, what is most likely to occur to the infected joint in septic arthritis?
1 - osteoperosis
2 - ankylosis
3 - osteomyelitis
4 - haemorrhage
2 - ankylosis
- stiffness of the joint due to abnormal adhesions
What are the 2 key symptoms (what a patient describes or experiences) in septic arthritis?
1 - pain in the joint
2 - swollen joint
3 - unable to weight bear or use the joint
4 - hair loss
1 - pain in the joint
3 - unable to weight bear or use the joint
All of the following are key signs (what a clinician sees as a manifestion of a disease/condition) in septic arthritis, EXCEPT which one?
1 - unwell patient/fever (unless diabetic)
2 - hot, red, tender and swollen joint
3 - joint in maximum volume
4 - hair loss
4 - hair loss
- microorganisms have PAMPs that elicit an immune response
- immune response leads to blood and fluid entering the joint
Septic arthritis can present in a similiar way to other conditions. All of the following are potential differentials, which is the LEAST likely?
1 - Crystal arthropathy (Gout or
Pseudogout)
2 - Cellulitis
3 - Bursitis
4 - Acute flare-up of RA
5 - Osteoarthritis
6 - Lyme disease
5 - Osteoarthritis
Although there are multiple investigations that need to be perfromed in a patient with suspected septic arthrits. But which one is the most urgeny?
1 - CRP
2 - joint aspiration
3 - WBC
4 - plain radiography
2 - joint aspiration
- all the other could be normal
Aspirating a joint is the most urgent investigation in a patient with suspected septic arthritis. Which of the following is NOT something that is commonly performed on a joint aspiration?
1 - gram staining
2 - cell counts
3 - collagen count
4 - cell culture
5 - crystal analysis
3 - collagen count
Which of the following is NOT a typically raised blood marker in a patient with suspected septic arthritis?
1 - WBC
2 - CRP
3 - LFTs
4 - Erythrocyte Sedimentation Rate (ESR)
3 - LFTs
- ESR is raised as RBCs can clump together and be heavier and they are likley to have more proteins, again making them heavier
Are imaging methods such as X-ray, MRI or CT useful?
- in acute setting maybe not
- but they can show boney changes
If a patient has suspected septic arthritis, should they wait for the bacterial culture results to come back or should they be treated with empirical antibiotics?
- start empirical antibiotics
- this can be changed once bacterial cell culture and antibiotic sensitivtiy resuls have been returned
In septic arthritis, should antibiotics be given orally or IV?
- IV
- quicker acting and this is most likely the location where the microorgansim has been able tonspread to the joint
Depending on the severity of the septic arthritis, which of the following is NOT an option for treatment?
1 - amputation
2 - surgical irrigation
3 - debridement of joint and any prothesis
4 - irrigation
1 - amputation
- in all of these we need to ensure we get tissue samples for diagnosis purposes
