What is the appropriate workup and management for a patient who develops a fever in the hospital?

Hospital Fever Workup

For any hospitalized patient who develops a new fever, begin with a focused clinical assessment to guide selective testing rather than ordering automatic laboratory and imaging studies. 1

Initial Clinical Assessment

Perform a targeted evaluation including:

• Review of recent procedures, surgeries, and indwelling devices (central lines, urinary catheters, drains) 1
• Focused physical examination of potential infection sites: surgical wounds, catheter entry sites, lung sounds, abdominal examination 1
• Medication review for drug-induced fever (antibiotics, chemotherapy within 60 days) 1
• Assessment for non-infectious causes: tissue necrosis (MI, stroke), malignancy, drug reactions 2

Core Diagnostic Studies

Obtain chest radiograph on all febrile patients as pneumonia is the most common infection causing fever in hospitalized patients 1

Blood cultures:

• Collect at least two sets (ideally 60 mL total) from different anatomical sites simultaneously 1
• If central venous catheter present, draw simultaneously from catheter and peripheral site to calculate differential time to positivity 1
• Sample at least two lumens if central line cultures indicated 1

Targeted Testing Based on Clinical Suspicion

For suspected urinary tract infection:

• Replace urinary catheter and obtain urine culture from newly placed catheter if pyuria present 1
• Avoid routine urine cultures in catheterized patients without symptoms 1

For suspected pneumonia or respiratory symptoms:

• Obtain lower respiratory tract specimen (sputum, tracheal aspirate, or bronchoscopic sample) before antibiotic initiation 1
• Consider viral nucleic acid amplification testing if upper respiratory symptoms present 1
• Test for SARS-CoV-2 based on community transmission levels 1

For diarrhea (>2 loose stools/day):

• Test for Clostridium difficile toxin if patient received antibiotics or chemotherapy within 60 days 1
• Avoid routine stool cultures for other bacteria unless patient admitted with diarrhea or is HIV-positive 1

For recent surgical patients (thoracic, abdominal, pelvic):

• Perform CT imaging in collaboration with surgical service if initial workup doesn't identify source 1
• For abdominal surgery or abdominal symptoms with abnormal liver enzymes, obtain formal abdominal ultrasound 1
• Avoid routine abdominal ultrasound in patients without abdominal signs, symptoms, or liver abnormalities 1

Advanced Imaging for Unclear Source

If initial workup fails to identify etiology:

• Consider 18F-FDG PET/CT if transport risk acceptable (sensitivity 85-100%) 1
• Thoracic ultrasound may help identify pleural effusions if chest X-ray abnormal and expertise available 1

Biomarkers for Bacterial Infection Probability

When bacterial infection probability is low-to-intermediate:

• Measure procalcitonin (PCT) or C-reactive protein (CRP) in addition to clinical evaluation 1
• Do not use PCT or CRP to rule out infection when bacterial infection probability is high 1

Common Pitfalls to Avoid

• Avoid automatic order sets that include unnecessary testing; let clinical assessment guide workup 1, 3
• Do not routinely culture urine in catheterized patients without pyuria or UTI symptoms 1
• Do not send stool for bacterial culture unless patient admitted with diarrhea, is HIV-positive, or part of outbreak investigation 1
• Older patients (>75 years) may have blunted febrile response to bacterial infections 2
• Consider non-infectious causes: 20% of hospital fever is from tissue necrosis (MI, stroke), and drug reactions are common 2

Temperature Measurement

Use core temperature methods when available (pulmonary artery catheter thermistor, bladder catheter, esophageal probe) over less reliable methods (axillary, tympanic, temporal artery) 1