Differential Diagnosis for Fever Patient

The following is a differential diagnosis for a patient presenting with fever, categorized for clarity and prioritization.

• Single Most Likely Diagnosis
  • Viral upper respiratory tract infection (e.g., common cold, influenza): This is often the most common cause of fever in outpatient settings, especially during seasonal peaks.
• Other Likely Diagnoses
  • Bacterial infections (e.g., pneumonia, urinary tract infections): These are common and can present with fever as a primary symptom. The specific type of infection can vary based on patient demographics, exposure history, and physical examination findings.
  • Influenza: Especially during flu season, influenza can be a very likely cause of fever, particularly if the patient has not been vaccinated.
  • Gastroenteritis: Viral or bacterial infections of the gastrointestinal tract can cause fever, along with symptoms like diarrhea and vomiting.
• Do Not Miss Diagnoses
  • Sepsis: Although not the most common cause of fever, sepsis is potentially life-threatening and requires immediate recognition and treatment. It can arise from any source of infection.
  • Meningitis: Infection of the meninges can present with fever, headache, and stiff neck. It is less common but critical to diagnose promptly due to its high morbidity and mortality if untreated.
  • Endocarditis: Especially in patients with a history of heart disease or intravenous drug use, endocarditis is a serious condition that can cause fever among other symptoms.
  • Tuberculosis (TB): In endemic areas or in patients with risk factors (e.g., immunocompromised, recent travel to or from areas with high TB prevalence), TB can present with chronic fever and should not be missed due to its public health implications and the need for specific treatment.
• Rare Diagnoses
  • Brucellosis: Typically associated with exposure to infected animals or their products, brucellosis can cause fever, fatigue, and swelling, among other symptoms.
  • Lymphoma: Certain types of lymphoma can present with fever of unknown origin, which is a fever that lasts for more than three weeks without a clear cause.
  • Factitious fever (Munchausen syndrome): Although rare, some patients may fabricate or induce fever for attention or other psychological reasons.
  • Autoimmune disorders (e.g., lupus, rheumatoid arthritis): These conditions can cause periodic fevers and are important to consider in patients with suggestive symptoms or a relevant history.