Chapter 14: Infectious Disease

3 degrees Celsius lasting three weeks without identified etiology, requiring systematic diagnostic evaluation through laboratory work and imaging. Sepsis and systemic inflammatory response syndrome represent critical clinical emergencies where bacterial infection triggers widespread inflammation, potentially progressing to severe sepsis with organ dysfunction and septic shock, demanding immediate intervention with broad-spectrum antimicrobial therapy and hemodynamic support. Bacterial infections span streptococcal diseases including pharyngitis, impetigo, and cellulitis, alongside serious conditions like necrotizing fasciitis and toxic shock syndrome, with potential sequelae such as acute rheumatic fever and glomerulonephritis. The chapter addresses bioterrorism-relevant organisms including anthrax, cholera, tetanus, and botulism, each requiring specific antitoxins and supportive management. Gastrointestinal bacterial pathogens such as Salmonella and Shigella necessitate careful fluid and electrolyte management alongside targeted antibiotic therapy. Viral infections covered include Epstein-Barr virus causing infectious mononucleosis, human papillomavirus with oncogenic potential, herpes simplex virus presenting with mucocutaneous lesions, and varicella-zoster virus causing disseminated disease. HIV and AIDS management focuses on antiretroviral therapy and opportunistic infection prophylaxis to restore immune function. Fungal infections predominantly affect immunocompromised populations and require antifungal agents selected based on pathogen identification and organ involvement. Parasitic infections including malaria, hookworm, and amebiasis are diagnosed through microscopic examination and serological testing, then managed with antiparasitic medications. Sexually transmitted infections such as syphilis, gonorrhea, chlamydia, and trichomoniasis present with genital symptoms and systemic manifestations requiring diagnosis through culture, nucleic acid amplification, and serology. Tick-borne illnesses including Lyme disease and Rocky Mountain spotted fever present characteristic rashes and systemic involvement, managed primarily with doxycycline therapy. Throughout, diagnostic approaches, clinical presentations, antimicrobial selection, and preventive strategies form the foundation for comprehensive infectious disease management.