Clinical Scenario:
A 12-year-old boy presents with 3 days of fever, severe myalgia, headache, nausea and abdominal discomfort. He has no cough or respiratory distress. His temperature is 38.8°C, pulse 118/min and blood pressure 100/65 mmHg.
Investigations show:
- Hemoglobin: 17.2 g/dL
- WBC: 18,500/mm³
- Platelets: 68 × 10⁹/L
- Serum creatinine: mildly elevated
- Chest radiograph: normal
His parents report that he recently helped clean a closed room with extensive rodent infestation.
Over the next several hours, he develops increasing tachypnea and oxygen requirement.
Which of the following is the most likely diagnosis?
A. Dengue fever
B. Hantavirus pulmonary syndrome
C. Leptospirosis
D. Influenza
E. Enteric fever
Correct Answer & Explanation:
Correct answer: B. Hantavirus pulmonary syndrome
Explanation:
The important feature in this case is the short febrile prodrome followed by rapid clinical deterioration. Hantavirus pulmonary syndrome (HPS) typically begins with fever, severe myalgia, headache and gastrointestinal symptoms. After this initial phase, patients may rapidly enter the cardiopulmonary phase, characterized by pulmonary edema, hypoxemia, hypotension and shock.
Several findings in this case provide additional clues:
- Marked thrombocytopenia
- Hemoconcentration (hemoglobin 17.2 g/dL), reflecting increased vascular permeability
- Leukocytosis
- Mild renal dysfunction
- Recent rodent exposure
- Rapid development of respiratory compromise despite an initially normal chest radiograph
The progression from a nonspecific febrile illness to rapid respiratory failure is characteristic of HPS.
Why not dengue? Dengue can cause fever, thrombocytopenia and hemoconcentration due to plasma leakage. However, the marked rodent exposure and abrupt progression to a cardiopulmonary syndrome favor hantavirus infection. Dengue should remain an important differential in endemic settings.
Why not leptospirosis? Leptospirosis can cause fever, renal dysfunction and pulmonary complications, but typically has additional clues such as conjunctival suffusion, jaundice or more prominent renal/hepatic involvement.
Why not influenza? Influenza can cause fever and myalgia and may progress to pneumonia, but thrombocytopenia with hemoconcentration and the characteristic rodent exposure make hantavirus more likely.
Why not enteric fever? Enteric fever usually has a more gradual course and does not characteristically cause abrupt pulmonary capillary-leak syndrome.
Key point: In a child with an acute febrile prodrome, thrombocytopenia + hemoconcentration + rodent exposure + rapidly developing respiratory distress should raise suspicion for hantavirus pulmonary syndrome.
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External Resources:
1. CDC — Clinician Brief: Hantavirus Pulmonary Syndrome
Explains rodent exposure, clinical progression, diagnostic testing, and the development of severe respiratory illness.
2. CDC — Hantavirus Pulmonary Syndrome: The 25th Anniversary of the Four Corners Outbreak
Peer-reviewed review of the characteristic laboratory pattern, capillary leak, pulmonary oedema, and cardiovascular deterioration.
Reference:
- Centers for Disease Control and Prevention. Clinician brief: hantavirus pulmonary syndrome (HPS) [Internet]. Atlanta: CDC; 2026 May 8.
- Koster F, Foucar K, Perez-Santiago E, et al. Hantavirus pulmonary syndrome—the 25th anniversary of the Four Corners outbreak. Emerg Infect Dis. 2018;24(11).
