Fever Diagnosis and Management Guidelines

Definition and Diagnosis

Fever may be the first sign of serious infection, especially in critically ill patients, and requires thorough evaluation 1

A comprehensive physical examination focusing on skin, mucous membranes, lymphadenopathy, hepatosplenomegaly, and neurological status is recommended 1, 2, 3
Initial laboratory investigations should include complete blood count, liver function tests, blood cultures, urinalysis, and urine culture 2, 3
Consider biomarkers such as serum procalcitonin and endotoxin activity assay to distinguish infectious from non-infectious causes 4

When infection is suspected, empirical antimicrobial therapy should be administered as soon as possible after cultures are obtained, with the American College of Critical Care Medicine recommending initiation within 1 hour after diagnosis of sepsis 1, 5
Initial empirical antibiotic therapy should target likely pathogens based on suspected source of infection, risk for multidrug-resistant pathogens, and local antimicrobial susceptibility patterns, as recommended by the Infectious Diseases Society of America 1, 5
For neutropenic fever, hospitalization and empiric therapy with vancomycin plus antipseudomonal antibiotics is recommended by the Infectious Diseases Society of America 6

Critically ill patients require thorough evaluation for "silent" sources of infection, with the Society of Critical Care Medicine recommending consideration of invasive diagnostic procedures if non-invasive tests are unrevealing 4
Returning travelers should have a detailed travel history obtained, including geographical locations visited, with the Centers for Disease Control and Prevention recommending consideration of malaria testing for all patients who have visited tropical countries within 1 year of presentation 2
Neutropenic patients require aggressive determination of etiology through aspiration/biopsy of skin and soft tissue lesions, with the Infectious Diseases Society of America recommending consideration of fungal infections for persistent or recurrent fever 6

Fever with signs of sepsis, such as hypotension, altered mental status, or tachypnea, requires immediate emergency care, as recommended by the American College of Emergency Physicians 1
High fever with muscle rigidity, possible malignant hyperthermia or neuroleptic malignant syndrome, requires immediate emergency care, with the American College of Critical Care Medicine recommending prompt intervention 1, 7