Differential Diagnosis for Acute Febrile Illness
Single Most Likely Diagnosis
- Viral upper respiratory tract infection: This is the most common cause of acute febrile illness, often presenting with symptoms such as cough, sore throat, and runny nose, in addition to fever.
Other Likely Diagnoses
- Influenza: Especially during flu season, influenza is a common cause of acute febrile illness, characterized by high fever, cough, sore throat, and muscle pains.
- Pneumonia: Can be caused by bacteria, viruses, or fungi, and presents with fever, cough, and difficulty breathing.
- Urinary tract infection: Especially in women, urinary tract infections can cause acute febrile illness, with symptoms including dysuria, frequent urination, and abdominal pain.
- Gastroenteritis: Infections of the gastrointestinal tract, often caused by viruses or bacteria, leading to fever, diarrhea, and vomiting.
Do Not Miss Diagnoses
- Meningitis: Although less common, meningitis is a life-threatening condition that requires immediate medical attention, presenting with fever, headache, stiff neck, and altered mental status.
- Sepsis: A severe and potentially life-threatening response to an infection, characterized by fever, tachycardia, tachypnea, and signs of organ dysfunction.
- Appendicitis: An acute abdominal condition that can present with fever, abdominal pain, and vomiting, requiring prompt surgical intervention.
- Endocarditis: An infection of the heart valves, which can be life-threatening if not treated promptly, presenting with fever, heart murmur, and signs of heart failure.
Rare Diagnoses
- Tuberculosis: A bacterial infection that can cause fever, cough, and weight loss, more common in immunocompromised individuals or those from endemic areas.
- Brucellosis: A zoonotic infection caused by bacteria, presenting with fever, fatigue, and swelling, often associated with contact with infected animals.
- Lymphoma: A type of cancer that can cause fever, night sweats, and weight loss, although it is much less common than infectious causes of acute febrile illness.
- Factitious fever: A condition where an individual falsifies or induces fever, often for attention or to avoid work, which is rare but important to consider in the differential diagnosis.