History-Taking in a Patient with Fever

1. History of Presenting Illness (HPI)

• When did the fever start? Was it sudden or gradual?
• How long has it been present? (Acute <2 weeks, subacute 2-4 weeks, chronic/FUO >3 weeks)

• Is it continuous, intermittent, or remittent?
• Does it spike at specific times of day or alternate days? (Tertian pattern in P. vivax malaria, quartan in P. malariae)
• Does it resolve completely between episodes?

• How high is the temperature, and by what method was it measured? (Oral, rectal, tympanic - use consistently)
• Note: Newborns, elderly, patients with chronic renal/hepatic failure, those on glucocorticoids or anticytokine therapy (anti-TNF, anti-IL-6, etc.) may have blunted febrile responses and present with low-grade or no fever despite active disease.

• Chills and rigors (suggest bacteremia or malaria)
• Sweating/drenching night sweats (TB, lymphoma, HIV, brucellosis)
• Weight loss (malignancy, TB, HIV)
• Fatigue, malaise, anorexia

• Respiratory: cough, sputum, dyspnea, hemoptysis
• GI: nausea, vomiting, diarrhea, abdominal pain, jaundice
• Urinary: dysuria, frequency, loin pain, hematuria (UTI, pyelonephritis)
• CNS: headache, neck stiffness, photophobia, altered consciousness (meningitis, encephalitis)
• Skin: rash, skin lesions, ulcers - ask specifically about timing relative to fever onset
• Joints: arthralgia, arthritis, joint swelling
• ENT: sore throat, ear pain, nasal discharge

2. Exposure History

• Recent international AND domestic travel
• Fever in a returned traveler significantly broadens the differential (malaria, typhoid, dengue, rickettsial disease, viral hemorrhagic fevers)
• Even remote travel history matters (e.g., M. tuberculosis, Strongyloides)
• Ask specifically about: food and water consumed during travel, freshwater swimming, animal contacts during travel, vaccinations taken prior to travel, malaria prophylaxis

• Pets at home (cats - Bartonella; dogs and ticks - Lyme, RMSF; reptiles - Salmonella)
• Farm animals (cattle, sheep, goats - Q fever / brucellosis)
• Rodent exposure (leptospirosis, rat-bite fever)
• Petting zoos, random encounters

• Raw/undercooked meat (STEC, Toxoplasma, Trichinella)
• Unpasteurized dairy (Salmonella, Listeria, M. bovis)
• Raw seafood (Vibrio, norovirus, helminths)
• Untreated water sources (Leptospira, enteric parasites)

• Exposure to sick individuals (respiratory droplet illnesses - TB, influenza, COVID-19)
• Healthcare setting exposure (drug-resistant organisms - MRSA, VRE, ESBL-producers, CRE)
• Previous hospitalizations or long-term care facility stays (nosocomial pathogens)

• Healthcare workers (TB, needlestick infections)
• Farmers (brucellosis, Q fever, leptospirosis)
• Funeral workers (TB)
• Laboratory workers (consider rare organism exposure)

• Unprotected sexual intercourse (HIV, STIs)
• IV drug use (endocarditis, hepatitis B/C, septicemia)
• Men who have sex with men

• Tick bites (Lyme disease, RMSF, ehrlichiosis, tularemia)
• Mosquito exposure (malaria, dengue, chikungunya, Zika)
• Sandfly exposure (leishmaniasis)

3. Past Medical History

• Previous similar episodes of fever - were they diagnosed?
• Chronic illnesses: diabetes, HIV/AIDS, malignancy, autoimmune disease, liver or renal failure, connective tissue disease
• Immunocompromised state: HIV infection, transplant recipient, chemotherapy, asplenia
• Recent surgeries or invasive procedures
• Implanted devices (prosthetic valves, joint replacements, central lines, pacemakers)

4. Drug and Medication History

• Complete medication list including over-the-counter drugs and herbal/dietary supplements
• Drug fever - many drugs can cause fever; classic offenders include beta-lactam antibiotics, phenytoin, hydralazine, allopurinol, procainamide
• Anticytokine therapy (anti-TNF, anti-IL-1, anti-IL-6, anti-IL-17): these patients are at high risk of serious and opportunistic infections (TB reactivation, systemic candidiasis), and may have a blunted febrile response - even low-grade fever requires aggressive evaluation
• Glucocorticoids (blunt febrile response)
• NSAIDs (may mask fever)
• Recent antibiotic use (alters cultures and can cause drug fever or C. difficile)
• Immunosuppressants

5. Family History

• TB or other infectious disease contacts at home
• Familial periodic fever syndromes (FMF, PFAPA, TRAPS, HIDS) if recurrent febrile episodes
• Malignancies (lymphoma, leukemia)
• Autoimmune diseases

6. Social History

• Living conditions: crowded housing, homeless shelter (TB risk)
• Country of origin / immigration history (endemic infections)
• Alcohol use (aspiration pneumonia, spontaneous bacterial peritonitis, liver disease)
• Tobacco use

7. Vaccination History

• Up-to-date status guides likelihood of vaccine-preventable illnesses
• Pre-travel vaccinations

Broad Categories to Keep in Mind (Table 20-1, Harrison's 22nd Ed.)