What are the different types of fever and their respective treatments?

Clinical Vignettes: Types of Fever and Their Management

Fever in Returned Travelers

Vignette 1: Malaria

A 32-year-old man presents with fever, headache, and myalgia 2 weeks after returning from a safari in Kenya. He did not take malaria prophylaxis.

Management approach:

• Malaria must be excluded first in all patients with fever returning from the tropics, as it is the most important potentially fatal cause 1
• Obtain up to three daily blood films immediately 1
• Most Plasmodium falciparum cases present within 1 month of return, but can present up to 6 months later 1
• Roughly half of malaria patients are afebrile on presentation, though almost all have a history of fever 1
• Look for complications: confusion, seizures, reduced Glasgow coma scale (cerebral malaria), hypoxia, tachypnea (respiratory complications) 1
• Treatment should be initiated urgently once diagnosis is confirmed, as delay increases mortality 1

Vignette 2: Enteric Fever (Typhoid)

A 28-year-old woman presents with fever, headache, and constipation 10 days after returning from visiting family in Pakistan. She received typhoid vaccination before travel.

Management approach:

• For clinically unstable patients with suspected enteric fever, start empiric IV ceftriaxone immediately after obtaining blood cultures 1
• Blood cultures have highest yield within the first week of symptoms (40-80% sensitivity) 1
• Fever is almost invariable; other symptoms are non-specific including headache, constipation/diarrhea, dry cough 1
• More than 70% of S. typhi isolates from Asia are fluoroquinolone-resistant; ceftriaxone is now first-line 1
• If fluoroquinolone resistance is confirmed, use azithromycin as oral alternative for uncomplicated disease 1
• Continue treatment for 14 days to reduce relapse risk 1
• Important pitfall: Vaccination provides incomplete protection and does not protect against paratyphoid 1

Vignette 3: Rickettsial Infection (African Tick Bite Fever)

A 45-year-old man develops fever and a characteristic eschar 7 days after a game park visit in South Africa.

Management approach:

• Start empiric doxycycline immediately if exposure to ticks in endemic areas, even before serologic confirmation 1
• Incubation period is 5-7 days (up to 10 days) 1
• Rickettsia africae is transmitted by cattle ticks and is common in travelers returning from safaris in southern Africa 1
• Patients should respond within 24-48 hours; if not, consider alternative diagnoses 1
• Alternative antibiotics include fluoroquinolones or azithromycin 1

Fever in Critically Ill Patients

Vignette 4: Sepsis in ICU Patient

A 65-year-old post-operative patient develops fever (38.5°C), tachycardia, and hypotension on post-operative day 3.

Management approach:

• When infection is suspected, administer empirical antimicrobial therapy within 1 hour after obtaining cultures, especially if the patient is seriously ill or deteriorating 1
• Obtain blood cultures before initiating antimicrobials 2
• Obtain chest radiograph for all patients with new fever in ICU 2
• For recent thoracic, abdominal, or pelvic surgery, consider CT imaging if etiology not readily identified 2
• Initial empirical therapy should cover resistant Gram-positive cocci (including MRSA) and Gram-negative bacilli if drug-resistant pathogens suspected 1
• Critical pitfall: Delay of effective antimicrobial therapy is associated with increased mortality 1, 2

Vignette 5: Drug Fever

A 58-year-old ICU patient develops persistent fever (38.8°C) on day 7 of antibiotic therapy with negative cultures and no clear infectious source.

Management approach:

• Consider drug fever when fever persists despite appropriate antimicrobial therapy and negative cultures 1
• Review all medications, including recently started antibiotics, anticonvulsants, and cardiovascular drugs 1
• Drug fever can occur with associated eosinophilia, rash, or isolated fever 1
• Discontinue suspected offending agent if clinically safe 1
• Important consideration: Patients who had anaphylaxis or toxic epidermal necrolysis should not be rechallenged 1

Vignette 6: Neuroleptic Malignant Syndrome

A 52-year-old agitated ICU patient receiving haloperidol develops high fever (40°C), muscle rigidity, and elevated creatinine phosphokinase.

Management approach:

• Recognize neuroleptic malignant syndrome as rare but important cause of fever in ICU 1
• Strongly associated with antipsychotic medications, particularly haloperidol in ICU setting 1
• Manifests as muscle rigidity generating fever and increasing creatinine phosphokinase 1
• Mechanism is central, unlike malignant hyperthermia which is peripheral 1
• Immediately discontinue offending neuroleptic agent 1

Fever in Special Populations

Vignette 7: Febrile Neutropenia

A 42-year-old woman with acute leukemia on chemotherapy presents with fever (38.5°C) and absolute neutrophil count of 300 cells/μL.

Management approach:

• For neutropenic patients with fever, hospitalize immediately and start empiric antibacterial therapy with vancomycin plus antipseudomonal antibiotics 2
• In high-risk neutropenic patients, use monotherapy with antipseudomonal β-lactam or carbapenem as empiric therapy 2
• Consider discontinuation of empiric antibiotics at 72 hours in low-risk patients with negative blood cultures who have been afebrile for at least 24 hours 2
• Obtain blood cultures before initiating therapy 2

Vignette 8: Q Fever (Chronic)

A 60-year-old man with prosthetic aortic valve presents with persistent low-grade fever and fatigue 6 months after exposure to sheep during farm visit. Phase I IgG titer is 1:2048.

Management approach:

• For chronic Q fever, treat with doxycycline 100 mg twice daily plus hydroxychloroquine 200 mg three times daily 1
• Diagnosis requires elevated phase I IgG titer (typically ≥1:1024) plus identifiable nidus of infection 1
• Perform baseline ophthalmologic examination before hydroxychloroquine treatment and every 6 months thereafter due to retinal toxicity risk 1
• Continue treatment for at least 18 months for native valve infections and at least 24 months for prosthetic valve infections 1
• Monitor monthly with serologic testing and clinical evaluations 1
• Critical pitfall: Do not treat based on elevated titers alone without clinical evidence of chronic infection 1

Fever Management Principles

Vignette 9: General Fever Management in ICU

A 70-year-old mechanically ventilated patient develops fever (38.5°C) without clear source. Nurse requests antipyretic order.

Management approach:

• Antipyretic medications should not be routinely used for the specific purpose of reducing temperature alone, as this has not been shown to improve mortality 2
• For patients desiring symptomatic relief, use antipyretic medications rather than non-pharmacologic cooling 2
• Use central temperature monitoring (pulmonary artery catheter, bladder catheter, esophageal thermistor) when available 2
• When central monitoring unavailable, use oral or rectal temperatures over less reliable axillary or tympanic measurements 2
• Key principle: Treat the patient and underlying cause, not the number on the thermometer 2

Vignette 10: Noninfectious Inflammatory Fever

A 55-year-old post-MI patient develops fever (38.3°C) on day 3 with clear lungs, negative cultures, and pericardial friction rub.

Management approach:

• Consider noninfectious inflammatory causes including Dressler syndrome (pericardial injury syndrome) 1
• Other noninfectious causes to consider: acute myocardial infarction, pulmonary infarction, gout, pancreatitis 1
• Blood product transfusion can cause fever 1
• Acalculous cholecystitis should be considered, especially in critically ill patients 1
• Perform bedside ultrasound of abdomen for patients with recent abdominal surgery or abdominal symptoms 2