Evaluation and Management of Prolonged High-Grade Fever

Initial Diagnostic Approach

The American College of Physicians recommends determining travel history to endemic areas within the past 3 weeks, particularly South Asia, sub-Saharan Africa, or Mediterranean regions, as enteric fever and rickettsial infections are common causes of prolonged fever in returned travelers 1
Assessing clinical stability is crucial, looking specifically for altered mental status, hypotension, tachycardia, respiratory distress, or signs of end-organ dysfunction, as these indicate the need for immediate empiric treatment 1
A thorough examination for localizing signs, including rash, lymphadenopathy, hepatosplenomegaly, conjunctival injection, oral mucosal changes, and extremity edema, is essential 1, 2
Documenting all medications started within the past 3 weeks is necessary, as drug-induced fever has a mean lag time of 21 days after drug initiation 3

Obtaining multiple sets of blood cultures before administering antibiotics is recommended, with the highest yield within the first week of symptoms for enteric fever, and a sensitivity of 40-80% 1
A complete blood count with differential can help identify neutropenia, thrombocytopenia, or atypical lymphocytes that may suggest malignancy, viral infection, or hematologic complications 3
Comprehensive metabolic panel assessment for hyponatremia, hypoalbuminemia, and elevated liver enzymes is common in enteric fever 1
Urinalysis and urine culture using a catheterized specimen can help identify UTI, which can present with isolated fever 3
Chest radiography is essential to evaluate for pneumonia, tuberculosis, or mediastinal lymphadenopathy 3

The Infectious Diseases Society of America recommends starting empiric antibiotics immediately without waiting for culture results if the patient is clinically unstable or deteriorating, with intravenous ceftriaxone as the first-line agent 1
The dosing of ceftriaxone should continue for 14 days to reduce relapse risk, with a relapse rate of less than 8% 1
Broadening coverage to include resistant gram-positive organisms, anaerobes, and antifungal therapy may be necessary if deep-seated infection or sepsis is suspected 4, 3

Enteric fever should be suspected strongly if fever duration is more than 2 weeks, as encephalopathy occurs in 10-15% of patients with illness more than 2 weeks 1
Stool and urine cultures become positive after the first week when blood culture yield decreases 1
The Widal test should not be used due to its lack of sensitivity and specificity 1
Newer rapid serological tests, such as Typhidot and Tubex, have shown mixed results and should not replace culture 1
Rickettsial infections should be considered if there is recent safari/game park exposure or Mediterranean travel 1
Treatment with doxycycline should produce a response within 24-48 hours; if no response, the diagnosis should be reconsidered 1

The Centers for Disease Control and Prevention recommend not relying on OTC antipyretics to guide management, as fever response to acetaminophen does not distinguish bacterial from viral infection 2
Vancomycin should not be added empirically without specific indications, as this promotes resistance 3
Travel-related infections should not be dismissed even with prophylaxis, as malaria can occur despite prophylaxis, and typhoid vaccination provides incomplete protection 1, 2

The World Health Organization recommends a total of 14 days of antibiotic therapy for enteric fever to reduce relapse risk 1
Adjusting the duration of antibiotic therapy based on sensitivities is necessary, with fluoroquinolones remaining the most effective option if the isolate is sensitive 1
Oral alternatives, such as azithromycin, are suitable for uncomplicated disease if fluoroquinolone resistance is confirmed, with a relapse rate of less than 3% 1