Causes

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Causes Evaluation of Postoperative Fever

• Jennifer Do

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Objectives

• What is postoperative fever?
• How is it characterized?
• What causes it?
• How do you evaluate your pt. with postoperative
  fever?

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What is fever?

• Normal
• Oral 35.6-38.5C (96-100.8F)
• Rectal 0.6C (1F) greater than oral
• Fever
• Oral gt38.0-38.5C (100.4-101.3F)
• is NOT always infection!
• Broad DDx is important in evaluation.

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How is postoperative fever characterized?

• Timing
• - Immediate onset in operating suite or
  within hours after operation
• - Acute within 1st week after
• - Subacute from 1 to 4 weeks after
• - Delayed gt1 month out

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Immediate Fever

• Differential Diagnosis
• Traumaprior to or as part of op
• Often caused by inflammatory stimulus of surgery
• Usually resolves spontaneously within 2-3 days
• Severity/Duration linked to longer, more
  extensive procedures
• Meds/Blood productsadverse rxns
• Immune mediated
• Vasodilation makes hypotension common sign
• Rash
• Malignant hyperthermia
• Usually presents within 30min starting inhalation
  anesthesia
• Infectionpresent prior to op

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Acute Fever

• DDx
• Pneumonia
• VAP Pts. on mechanical ventilation at increased
  risk
• Aspiration risks anesthesia/analgesia, NG tube
• UTI
• Indwelling urethral catheters risk increases
  with duration
• More common in GU pts. or those with chronic
  catheters pre-op
• Surgical site infections
• Group A strep
• Clostridium perfringens
• IV catheter exit site infections and associated
  bacteremia
• Should be considered in any pt. with catheter
  placed
• Nosocomial infections
• Community acquired infections
• Noninfectious causes
• Pancreatitis, MI, PE, thrombophlebitis, EtOH
  withdrawal, acute gout

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Subacute Fever

• DDx
• Surgical site infection
• IV catheter infections
• Thrombophlebitis
• DVT and PE risk impaired mobility
• Antibiotic associated diarrhea
• Clostridium difficile
• Drug Fever
• Sulfas, H2 blockers, heparin, phenytoin

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Delayed Fever

• DDx
• Infection
• SSI from more indolent organisms
• Blood transfusion
• Viral CMV, hepatitis, HIV
• Parasitic toxo, babesiosis, plasmodium malariae
• Infective endocarditis

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Causes Infectious vs. Non-infectious
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Approach to the Feverish Patient

• Evaluate patient systemically taking into account
  timing of onset and the diversity of causes
• Initial screen What do we do?
• Wind
• Water
• Wound
• Walking
• Wonder drugs
• Worm

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Approach (contd)
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The Moral of the Story

• What is postoperative fever?
• Oral temp gt38.0-38.5C
• How is it characterized?
• Timing immediate, acute, subacute, delayed
• What causes it?
• Infectious vs. non-infectious
• How do you evaluate your pt?
• Think 6Ws,
• gt do HP,
• narrow down ddx with labs/imaging

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Take Home Points

• Fever is common in the first few days after an
  operation and usually resolves spontaneously
• Atelectasis is not a cause of fever.
• It is critical that physicians be able to
  recognize the minority of fevers that demand
  immediate attention
• Avoid the shotgun approachstart with HP