Primary Treatment for Fever Due to Infection
When clinical evaluation suggests infection is the cause of fever, empiric antimicrobial therapy should be administered as soon as possible after cultures are obtained, especially if the patient is seriously ill or deteriorating. 1
Pathophysiology of Fever in Infection
Fever is a common early indicator of infection, occurring in 26-88% of adult ICU patients 1. It represents a physiologic mechanism that has beneficial effects in fighting infection rather than being a primary illness itself 2. When evaluating fever, it's crucial to distinguish between infectious and non-infectious causes.
Diagnostic Approach
- Determine whether fever represents initial onset, persistent unexplained fever (after 4-7 days), or a recurrent episode 1
- Aggressively determine the etiology through appropriate cultures and diagnostic tests before initiating therapy when possible 1
- Central temperature monitoring methods (thermistors for pulmonary artery catheters, bladder catheters, or esophageal balloon thermistors) are preferred when accurate temperature measurements are critical 1
- Blood cultures should be obtained before initiating antimicrobial therapy 1
Empiric Antimicrobial Therapy
When to Initiate Therapy:
- Initiate empiric therapy when clinical evaluation suggests infection is the cause of fever 1
- Begin antimicrobial therapy within 1 hour after the diagnosis of sepsis is considered 1
- Therapy may be necessary for unstable or high-risk patients while diagnostic evaluation is ongoing 1
Selection of Empiric Therapy:
Direct initial empiric antibiotic therapy against likely pathogens based on:
- Suspected source of infection
- Patient risk for multidrug-resistant pathogens
- Local antimicrobial susceptibility patterns 1
For patients with neutropenia and fever:
For community-acquired pneumonia in adults appropriate for oral therapy:
For pediatric patients with community-acquired pneumonia:
Antipyretic Therapy
The use of antipyretics in febrile patients with infection remains controversial:
- Evidence does not currently support routine antipyretic administration 4
- The primary goal should be to improve overall comfort rather than normalize body temperature 2
- A randomized controlled trial showed that early administration of acetaminophen to treat fever due to probable infection did not affect the number of ICU-free days 5
Important Considerations and Pitfalls
- Non-infectious causes of fever should always be considered in the differential diagnosis (including drug fever, withdrawal syndromes, inflammatory conditions) 1
- Delay of effective antimicrobial therapy has been associated with increased mortality from infection and sepsis 1
- For patients with drug-resistant pathogens, initial broad-spectrum empirical antimicrobial therapy directed against both resistant Gram-positive cocci and Gram-negative bacilli may be required 1
- Documented clinical and microbiologic infections should be treated based on antimicrobial susceptibilities of isolated organisms once available 1
- Treatment duration for most bacterial skin and soft tissue infections should be 7-14 days 1
Remember that while treating the underlying infection is the primary approach to fever management, fever itself may have beneficial effects in fighting infection, and routine antipyretic use should be carefully considered based on the patient's overall condition and comfort.