What is the initial approach to a patient presenting with fever during a fever workup?

From the Guidelines

The initial approach to a patient presenting with fever involves a thorough history and physical examination, followed by targeted laboratory and imaging studies, with empiric antimicrobial therapy initiated promptly if bacterial infection is suspected, especially in patients with signs of sepsis. Begin by assessing vital signs, including temperature pattern, and obtaining a detailed history about the fever's onset, duration, associated symptoms, recent travel, exposures, and underlying medical conditions 1. Perform a comprehensive physical examination to identify potential sources of infection, paying particular attention to the skin, respiratory system, abdomen, and neurological status. Initial laboratory tests should include complete blood count with differential, comprehensive metabolic panel, urinalysis, and blood cultures (two sets from different sites before starting antibiotics) 1. Additional tests may include chest X-ray, urine culture, and specific tests based on clinical suspicion.

Some key considerations in the initial approach include:

• Assessing the risk for complications of severe infection, which may determine the type of empirical antibiotic therapy and venue of treatment 1
• Identifying high-risk patients who require hospital admission for empirical therapy, such as those with anticipated prolonged and profound neutropenia or significant medical co-morbid conditions 1
• Considering the use of empirical antifungal therapy in patients with persistent fever that does not respond to empirical antibiotic therapy 1
• Initiating antibiotic therapy within 1 hour after the diagnosis of sepsis is considered, with the choice of regimen depending on the suspected infectious etiology and local resistance patterns 1

Empiric antimicrobial therapy should be guided by the likely source of infection, local resistance patterns, and patient factors, with the goal of reducing morbidity and mortality. For example, in suspected community-acquired pneumonia, a respiratory fluoroquinolone or combination of a beta-lactam plus macrolide might be appropriate 1. This systematic approach helps identify the source of fever while ensuring timely treatment of potentially serious infections.

From the FDA Drug Label

1.2 Empiric Therapy for Febrile Neutropenic Patients Cefepime Injection as monotherapy is indicated for empiric treatment of febrile neutropenic patients

The initial approach to a patient presenting with fever during a fever workup is empiric therapy.

• Cefepime Injection can be used as monotherapy for empiric treatment of febrile neutropenic patients.
• However, in patients at high risk for severe infection, antimicrobial monotherapy may not be appropriate 2.
• The need for continued antimicrobial therapy should be re-evaluated frequently in patients whose fever resolves but who remain neutropenic for more than 7 days.

From the Research

Initial Approach to Fever Workup

The initial approach to a patient presenting with fever during a fever workup involves a comprehensive evaluation to determine the underlying cause of the fever.

• A thorough history and physical examination are essential in narrowing down potential etiologies 3, 4, 5, 6, 7.
• The differential diagnosis for fever is broad and can be categorized into infection, malignancy, noninfectious inflammatory disease, or miscellaneous causes 3, 5.

Diagnostic Evaluation

• Initial testing should include an evaluation for infectious etiologies, malignancies, inflammatory diseases, and miscellaneous causes such as venous thromboembolism and thyroiditis 3.
• Laboratory tests, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, can help guide further evaluation 3.
• Imaging studies, such as computed tomography (CT) scans, may be useful in reaching a diagnosis, especially if ESR or CRP levels are elevated 3.
• In some cases, invasive tests such as tissue biopsies may be necessary to establish a diagnosis 3.

Special Considerations

• In patients with neutropenia, empiric antimicrobial therapy may be necessary, even if the source of infection is not yet identified 7.
• A detailed medical history and thorough physical examination are crucial in evaluating patients with fever and rash, as certain causes can be medical emergencies 6.
• The approach to fever workup may vary depending on the clinical context, such as in patients with chemotherapy-induced neutropenia or those presenting to the emergency department 4, 7.