Approach to Acute Febrile Illness

Approach to Acute Febrile Illness

Initial Assessment

History: Obtain a detailed history, including onset and duration of fever, associated symptoms (e.g., cough, sore throat, rash), recent travel or exposures, medical history, medications, allergies.
Physical Examination: Perform a thorough examination to identify focal signs of infection (e.g., lung crackles, meningeal irritation) or systemic involvement.

Classification

Determine if the fever is due to an infectious cause by assessing for localizing symptoms and signs:
Upper respiratory tract infections: Cough, rhinorrhea.
Lower respiratory tract infections: Dyspnea, tachypnea, crackles.
Gastrointestinal infections: Diarrhea, abdominal pain.
Genitourinary infections: Dysuria, flank pain.
Consider non-infectious causes (e.g., autoimmune diseases) if no clear infectious source is found.

Diagnostic Workup

Laboratory Tests:
Complete blood count (CBC), differential to assess for leukocytosis or left shift.
Blood cultures in febrile patients with suspected bacteremia, especially those at risk of endocarditis or sepsis.
Urinalysis and urine culture if genitourinary symptoms are present.
Imaging: Chest X-ray if respiratory symptoms; CT scans if focal signs suggest abscesses (e.g., liver, brain).
Molecular Tests: PCR for specific pathogens (e.g., COVID-19, influenza) or serology when indicated.

Management

Empiric Therapy:
Start antibiotics promptly in suspected bacterial infections (e.g., pneumonia), guided by local resistance patterns.
Avoid unnecessary antipyretics if fever is a diagnostic clue; use judiciously to improve comfort without masking symptoms.
Supportive Care: Hydration, rest, and monitoring for complications like sepsis.

Special Considerations

Critically Ill Patients: Rapid evaluation with broad-spectrum antibiotics in suspected sepsis or septic shock.
Fever of Unknown Origin (FUO): Extensive workup if fever persists beyond 3 weeks without clear cause; consider autoimmune, neoplastic, and infectious etiologies.

Follow-Up

Reassess within 48–72 hours to confirm response to treatment or adjust therapy based on culture results.
Consider specialist consultation (e.g., Infectious Disease) for complex cases.

Key Points:

Fever is a symptom; the goal is identifying and treating its underlying cause.
Early recognition of severe infections (e.g., meningitis, sepsis) is critical.