Septic Arthritis

Question 1

What is septic arthritis?

Answer 1

It is defined as an orthopaedic emergency, in which there is infection and inflammation within a joint

Question 2

What joint is most commonly affected by septic arthritis?

Answer 2

Knee Joint

Question 3

What is the pathophysiological cause of septic arthritis?

Answer 3

The organism transmission tends to occur secondary to hematogenous spread from distant abscesses, wounds, respiratory tract infections or sexually transmitted infections

Question 4

What nine risk factors are associated with septic arthritis?

Answer 4

Osteoarthritis

Rheumatoid Arthritis

Crystal Arthropathies

Joint Prosthesis

Immunosuppression

Diabetes Mellitus

Sickle Cell Disease

Intravenous Drug Use

Alcoholism

Question 5

What are the six clinical features of septic arthritis?

Answer 5

Fever > 38C

Joint Pain

Joint Swelling

Joint Warmth

Joint Erythema

Reduced Joint Movement

Question 6

What two investigations are used to diagnose septic arthritis?

Answer 6

Blood Tests

Joint Arthrocentesis

Question 7

What four blood test results indicate septic arthritis?

Answer 7

Increased WCC Levels

Increased CRP Levels

Increased ESR Levels

Blood Culture Positive

Question 8

What is the gold standard investigation used to diagnose septic arthritis?

Answer 8

Joint Arthrocentesis

Question 9

When should joint arthrocentesis be used to diagnose septic arthritis?

Answer 9

It should be conducted in all cases in which there is presentation of a hot, swollen, tender joint with restricted movement

Question 10

What four synovial fluid analysis results indicate septic arthritis?

Answer 10

Yellow/Green Fluid Colour

Increased WCC Levels

Increased Neutrophil Levels

Positive Bacterial Culture

Question 11

What eight causative organisms are associated with septic arthritis?

Answer 11

Staphylococcus Aureus

Streptococcus Pneumoniae

Neisseria Gonorrhoea

Mycobacterium Tuberculosis

Methicillin Resistant Staphylococcus Aureus (MRSA)

Streptococcus Pyogenes

Haemophilus Influenza

Escherichia Coli

Question 12

What is the most common causative organism associated with septic arthritis?

Answer 12

Staphylococcus Aureus

Question 13

When does Neisseria Gonorrhoea tend to cause septic arthritis?

Answer 13

It is the most common causative organism of septic arthritis in sexually active young patients - due to disseminated gonococcal infection

Question 14

When does Mycobacterium Tuberculosis tend to cause septic arthritis?

Answer 14

It is the most common causative organism of septic arthritis in immunocompromised patients and those from areas of high tuberculosis prevalence

Question 15

When does Methicillin Resistant Staphylococcus Aureus (MRSA) tend to cause septic arthritis?

Answer 15

It is the most common causative organism in nursing home residents and those recently discharged from hospital

Question 16

What criteria is used to diagnose septic arthritis?

Answer 16

Kocher Criteria

Question 17

How is the Kocher criteria used to diagnose septic arthritis?

Answer 17

It is used to determine the septic arthritis probability, based upon clinical features and investigation findings

Question 18

What are the four Kocher criteria?

Answer 18

Non-Weight Bearing On Affected Side= 1 Score

ESR Level > 40mm/Hr = 1 Score

Fever > 38.5C = 1 Score

WCC > 12,000 Cells/mm3 = 1Score

Question 19

What does a Kocher score of 1 indicate?

Answer 19

3% chance of septic arthritis

Question 20

What does a Kocher score of 2 indicate?

Answer 20

40% chance of septic arthritis

Question 21

What does a Kocher score of 3 indicate?

Answer 21

93% chance of septic arthritis

Question 22

What does a Kocher score of 4 indicate?

Answer 22

99% chance of septic arthritis

Question 23

What is the pharmacological management option of septic arthritis?

Answer 23

Antibiotic Therapy

Question 24

When is antibiotic therapy used to manage septic arthritis?

Answer 24

It is the first line management option

Question 25

What is the first line empirical antibiotic used to manage septic arthritis?

Answer 25

Flucloxacillin

Question 26

What is the first line empirical antibiotic used to manage septic arthritis - in penicillin allergic individuals?

Answer 26

Clindamycin

Question 27

Describe the antibiotic regime used to manage septic arthritis

Answer 27

It is administered intravenously for a period of 2 weeks, before being switched to an oral course for a period of 2 – 4 weeks Therefore, the total antibiotic course is 4 – 6 weeks long

Question 28

Which two antibiotics are administered once culture confirms Neisseria Gonorrhoea infection?

Answer 28

Cefotaxime OR Ceftriaxone

Question 29

Which two antibiotics are administered once culture confirms MRSA infection?

Answer 29

Vancomycin OR Teicoplanin

Question 30

What is the surgical management option of septic arthritis?

Answer 30

Arthroscopic Lavage

Question 31

What is arthroscopic lavage?

Answer 31

It involves aspiration of intra-articular fluid and washing out of contents inside a joint space

Question 32

What are the three complications associated with septic arthritis?

Answer 32

Joint Destruction Septic Shock Osteomyelitis