Fever

Adult

Common Infectious Etiologies

• Viral illness: Influenza, CMV, EBV

• HEENT: Sinusitis, dental infection

• Pneumonia

• GI/Abdomen: Ascending cholangitis, appendicitis, spontaneous bacterial peritonitis

• GU: Urinary tract infection, pelvic inflammatory disease

• Cellulitis

• Meningitis

• Sepsis

Fever of Unknown Origin Considerations

• Drug-induced fever

• Infectious: Tick-borne illness, tuberculosis (pulmonary and extrapulmonary), endocarditis, osteomyelitis, prostatitis, HIV

• Malignancy: Leukemia, lymphoma, pancreatic cancer, colon cancer

• Autoimmune disease: Rheumatoid arthritis, inflammatory bowel disease, polymyalgia rheumatica, SLE, adult onset Still’s disease (rare)

• Vasculitis: Giant cell (temporal) arteritis, Takayasu's arteritis, ANCA-associated vasculitides, Wegener's granulomatosis/microscopic polyangiitis

Hot Flashes and Flushing

• Menopause: 45+ y/o F with 12+ months amenorrhea and no alternative biophysiologic explanation

  • Hot flashes, irregular menses, vaginal dryness, dyspareunia, sleep disturbances, depression/mood change

  • Labs

    • TSH if concern for hyperthyroidism

    • Age < 45 with amenorrhea: Obtain hCG, prolactin, TSH, FSH

  • Counseling: Expectations per STRAW staging system

• Emotional flushing (embarrassment)

• Flushing due to medications/food/alcohol

• Rare: Paraneoplastic syndromes

  • Renal cell carcinoma

  • Endocrine tumors

    • Medullary thyroid carcinoma of the thyroid

    • Pheochromocytoma

    • Pancreatic islet-cell tumors

    • Carcinoid syndrome

Additional reading: Differential Diagnosis of Hot Flashes

Pediatric

Etiology

• Neonatal/Infants

  • General approach 0 to 90 days

  • Bacterial meningitis

• Children

  • Constipation

  • Viral illness: Febrile seizure, meningitis

  • Bacterial infection: Otitis media, streptococcal pharyngitis, pneumonia, UTI, meningitis

  • Drug-induced fever

Fever of Unknown Origin

Fever of unknown origin definition: Present on most days for at least 3 weeks with unclear etiology after 1 week of intense investigation

• Etiology

  • Common conditions with atypical presentation (most common)

  • Infection

  • Neoplastic disorders

  • Autoimmune disease

  • Vasculitis: Henoch-Schönlein purpura, Kawasaki disease, Behçet's disease

• Diagnosis

  • Aerobic and anaerobic blood cultures, CBC with manual differential, peripheral blood smear, CMP, ESR, CRP

  • Urinalysis with culture

  • CXR