What to ask a patient with a chief complaint of prolonged fever?

Evaluation of Prolonged Fever (10 Days Duration)

For a patient presenting with 10 days of fever, immediately obtain a detailed travel history, exposure history (including contact with sick individuals), medication history, presence of indwelling devices, immunization status, and systematically assess for localizing symptoms across all organ systems, as this structured approach identifies life-threatening infections and guides targeted diagnostic testing. 1, 2

Essential Historical Elements

Travel and Exposure History

• Document specific destinations, dates of travel, duration, and activities during travel, as certain infections have geographic distributions and incubation periods that align with prolonged fever 3
• Ask about contact with individuals diagnosed with SARS or other respiratory infections within the past 10 days, as the median incubation period for SARS is 5 days (range 2-10 days) 4
• Inquire about exposure to animals, unpasteurized dairy products, and occupational exposures, as these increase risk for infections like Q fever that present with prolonged fever 5

Medication and Immunization History

• Obtain complete list of all medications, including recent antibiotics, as prior antibiotic use is a major cause of culture-negative infections and can mask serious bacterial infections 4
• Document immunization status (fully, partially, or not immunized), particularly pneumococcal and other routine vaccines, as this affects risk stratification for serious bacterial infections 4
• Ask specifically about antipyretic use in the preceding days, as this may suppress fever and alter clinical presentation 4

Medical History and Risk Factors

• Identify underlying conditions including diabetes, cardiopulmonary disease, heart valve abnormalities, vascular grafts, aneurysms, and immunosuppression, as these are associated with more severe outcomes and chronic infections like endocarditis 4, 5
• Document presence of any indwelling devices (central venous catheters, urinary catheters, prosthetic valves), as these are common sources of prolonged fever 2
• Ask about recent dental procedures or poor oral hygiene, as periodontal disease is strongly associated with bacteremia and endocarditis 4

Systematic Review of Systems

Fever Characteristics

• Determine the pattern of fever (continuous, intermittent, relapsing), maximum recorded temperature, and method of temperature measurement, as fever patterns and home thermometer accuracy affect clinical assessment 4, 6
• Note that fever may be absent despite serious infection, particularly in elderly and immunocompromised patients, so normal temperatures do not exclude infection 1, 6

Localizing Symptoms by System

Respiratory symptoms:

• Ask about cough, dyspnea, sputum production, and chest pain, as respiratory symptoms typically begin 3 days after fever onset in conditions like SARS and pneumonia 4
• Document any upper respiratory symptoms, as these warrant viral pathogen testing 2

Gastrointestinal symptoms:

• Inquire about diarrhea, abdominal pain, nausea, and vomiting, as some serious infections like SARS present with gastrointestinal symptoms 4

Genitourinary symptoms:

• Ask about dysuria, frequency, urgency, flank pain, and hematuria, as urinary tract infections are common causes of prolonged fever 4, 2

Cardiovascular symptoms:

• Document any new heart murmurs, chest pain, or signs of heart failure, as these suggest endocarditis, which can present with prolonged fever 4

Neurological symptoms:

• Ask about headache, altered mental status, focal neurological deficits, neck stiffness, and photophobia, as these indicate potential CNS infection requiring immediate evaluation 2
• Inquire about vivid dreams or hallucinations, as these are reported fever-associated symptoms 7

Musculoskeletal symptoms:

• Document myalgias, arthralgias, joint swelling, and back pain, as these accompany many febrile illnesses and may suggest specific diagnoses 4, 7

Dermatological findings:

• Ask about and examine for rash, eschars, or skin lesions, as the presence of rash makes SARS less likely but may indicate other infections 4

Constitutional symptoms:

• Systematically assess for chills, rigors, night sweats, weakness, malaise, and weight loss, as these are common fever-associated symptoms that help characterize the illness 4, 7

Critical Red Flags Requiring Immediate Action

• Any alteration in consciousness or focal neurological signs mandates immediate evaluation for CNS infection, including lumbar puncture after appropriate imaging if focal signs present 2
• Signs of septic shock or hemodynamic instability require immediate blood cultures (at least two sets from different sites) followed by empirical antimicrobial therapy 2
• Respiratory distress or oxygen saturation <92% on room air necessitates immediate assessment including chest imaging and arterial blood gas 4

Common Pitfalls to Avoid

• Do not initiate empirical antibiotics for undefined febrile illness without obtaining blood cultures first, as this is a major cause of culture-negative infections and obscures diagnosis 4, 2
• Do not rely solely on oral temperatures if fever is suspected, as they have poor sensitivity; obtain core temperatures when concern exists 6
• Do not assume absence of leukocytosis excludes infection, as white blood cell count may be normal in up to 75% of patients with prolonged fever, particularly in elderly patients 1
• Do not overlook non-infectious causes of prolonged fever, including malignancy, autoimmune conditions, and drug fever, based on the clinical context 6