Post Operative Fever

Question 1

What are the DDx for post operative fever?

Answer 1

The Big Five:
• Surgical site 
• IV sites
• UTI
• Pneumonia 
• DVT

Question 2

Causes of IMMEDIATE post op fever

Answer 2

a. Usually mild fever (often benign) due to:
• Transfusion reaction, medication reaction
• Infection prior to surgery
• Trauma
b. Malignant hyperthermia (very rare)

Question 3

Causes of ACUTE (first week) post op fever

Answer 3

– Hospital acquired pneumonia/ aspiration pneumonia
– IV site infection with bacteraemia
– Urinary tract infection
– Surgical sites

Question 4

Causes of SUB ACUTE ( after first week) post op fever

Answer 4

– Surgical sites
– IV sites
– DVT
– Drug reactions (antibiotics, phenytoin, others) – Other nosocomial infections, esp if in ICU

Question 5

Causes of DELAYED (after a month) post op fever

Answer 5

– Surgical site

– Viruses and transfusion (CMV)

Question 6

What dose a swinging fever (spiking temperature) indicate?

Answer 6

Accumulation of pus - abscess, empyema, subdiaphragmatic abscess, epidural abscesses

Question 7

How do you distinguish the big five DDx for post op fever?

Answer 7

On history ask about:
• Symptoms of fever
• Pain in the of op, duration, movement, restricted, analgesic requirements
• Shortness of breath, cough, sputum production, pleuritic chest pain
• Urinary catheter-in-situ, dysuria, frequency
• Pain in the calves, peripheral IV sites

Question 8

Steps of examination in post op fever

Answer 8

• Vital signs- eg. BP, pulse, respiratory rate (tachypnoea), O2 saturation, temperature
• Surgical wound
• IV sites/Spinal site
• Chest
• Legs
• Skin (rash)

Question 9

Key factors when examining the surgical site

Answer 9

• Inspection- erythema, haematoma, wound breakdown, discharge
• Palpate- tenderness, fluctuance, crepitus
• +/- imaging

Question 10

Key factors when examining the IV and other invasive sites

Answer 10

• IV, arterial line, central line, drain site- inspect all sites, note date inserted, when they were changed
• Drains sites may get infected or be an indicator of deep infection- purulent fluid
• Central line-associated bloodstream infections usually have no localising signs

Question 11

Key factors when examining the urinary tract

Answer 11

• Was a catheter used or still in situ- is it blocked? What colour is the urine?
• (Bacteruria very common in catheterised patients, but often asymptomatic and not requiring treatment)

Question 12

Key factors when examining the lungs

Answer 12

• Chest signs- crepitations, dullness to percussion: ? consolidation, ? effusion
• Pulmonary infection versus pulmonary embolus
• NB other non infectious causes of chest signs: ARDS, left ventricular failure/fluid overload

Question 13

Key factors when examining the legs

Answer 13

• DVT- swelling, tender calf, or no signs but high risk
• Check thromboprophylaxis- eg. TEDS, Clexane, Pneumatic calf compressors
• Investigate- Doppler US

Question 14

What are the risk factors for surgical site infection?

Answer 14

• Host factors: age, obesity, malnutrition, diabetes, steroids, smoking, infection at another site, skin carriage of Staph aureus
• Type of surgery, wound class, surgical technique, operation duration, hair removal, skin prep used, hypothermia
• Inadequate surgical antibiotic prophylaxis- antibiotic choice, timing
• Theatre traffic

Question 15

Treatment of post op fever due to surgical site infection

Answer 15

• Abx

- If infection of site or joint, then complete evacuation of infected site, lavage of joint (wash out well!)

Question 16

What percentage of MRSA infections of all S. aureus infections?

Answer 16

15-20%

Rx with vancomycin