Approach to Fever with Chills
For patients presenting with fever and chills, immediately obtain accurate temperature measurement (oral or rectal preferred), perform a chest radiograph, collect at least two sets of blood cultures from different anatomical sites, and initiate a systematic evaluation prioritizing infectious causes—particularly bacteremia, which has a 2.8-fold increased risk when chills are present.
Temperature Measurement
Use oral or rectal temperatures as your standard measurement method 1. Avoid axillary, tympanic, temporal artery, or chemical dot thermometers as these are unreliable. If the patient has central monitoring devices (pulmonary artery catheter, bladder catheter, esophageal thermistor), use these for the most accurate readings.
Clinical Significance of Chills
Chills are a critical diagnostic clue that substantially increases the probability of bacteremia. When chills accompany fever, the relative risk for bacteremia is 2.8 (95% CI: 2.1-3.8), with a positive predictive value of 31% and negative predictive value of 89% 2. This correlation is particularly strong in urinary tract infections (48% positive predictive value) compared to respiratory infections (24% positive predictive value) 2.
Initial Diagnostic Workup
Mandatory First-Line Testing
- Chest radiograph: Perform this in all patients with new fever 1
- Blood cultures: Collect at least two sets (ideally 60 mL total blood) simultaneously from different anatomical sites without time intervals between draws 1
- If central venous catheter present: Draw simultaneous peripheral and central cultures from at least two lumens to calculate differential time to positivity 1
Respiratory Symptoms Present
If the patient has cough or upper respiratory symptoms, test for viral pathogens using nucleic acid amplification panels 1. Always test for SARS-CoV-2 based on community transmission levels 1.
Urinary Symptoms or Pyuria
If urinary tract infection is suspected with pyuria, replace the urinary catheter first, then obtain cultures from the newly placed catheter 1.
Imaging Strategy Based on Clinical Context
Post-Surgical Patients
For recent thoracic, abdominal, or pelvic surgery: If initial workup doesn't identify an etiology, perform CT imaging in collaboration with the surgical service 1.
Abdominal Evaluation
- Without abdominal signs/symptoms: Do NOT routinely perform abdominal ultrasound or POCUS 1
- With abdominal symptoms, recent surgery, or abnormal liver enzymes: Perform formal bedside diagnostic ultrasound 1
Thoracic Imaging
If chest radiograph is abnormal, perform thoracic bedside ultrasound (when expertise available) to better identify pleural effusions and parenchymal pathology 1
Procalcitonin Use
Use procalcitonin selectively based on pre-test probability:
- Low-to-intermediate probability of bacterial infection: Measure procalcitonin in addition to clinical evaluation 1
- High probability of bacterial infection: Do NOT use procalcitonin to rule out infection 1
This stratified approach prevents both under-diagnosis in uncertain cases and unnecessary testing when bacterial infection is clinically evident.
Antipyretic Management
Avoid routine antipyretic use solely for temperature reduction 1. The evidence suggests fever may have protective effects in critically ill patients. However, if the patient values comfort and symptom relief, use pharmacologic antipyretics rather than nonpharmacologic cooling methods 1.
Advanced Imaging for Unclear Etiology
When all initial diagnostic tests fail to establish an etiology, consider 18F-fluorodeoxyglucose PET/CT if transport risk is acceptable 1. WBC scans have insufficient evidence to recommend 1.
Prognostic Considerations
Bacteremia, advanced age, and serious comorbidity are unfavorable prognostic factors 2. Mortality risk increases significantly with bacteremia (RR: 1.1) and serious comorbidity (RR: 6.1) 2. Patients who died were significantly older than those discharged, emphasizing the need for heightened vigilance in elderly patients presenting with fever and chills.
Common Pitfalls to Avoid
- Don't rely on axillary or tympanic temperatures—they miss true fever
- Don't delay blood cultures—draw before antibiotics when possible
- Don't assume absence of fever rules out infection in elderly or immunocompromised patients 3
- Don't perform routine abdominal imaging without clinical indicators—this wastes resources and delays appropriate workup 1
- Don't use rapid molecular blood tests without concomitant blood cultures 1