Pneumonic plague is caused either by direct inhalation of infective
respiratory droplets or aerosolized bacteria, or by secondary
spread of infection to the lungs from another anatomic site.
Chest radiographs of untreated patients show rapidly expanding
bronchopneumonic infiltrates. Pulmonary parenchymal necrosis and
hemorrhage occur, and patients occasionally develop pulmonary
abscesses and resultant cavities. Enlarged hilar nodes and pleural
effusions may be present.
It has the following characteristics:
- Incubation Period- 2-4 days with range of 1-6 days.
- Acute onset of fever, chills, malaise, and myalgias associated
with progressive lethargy.
- A productive cough of copious watery mucoid sputum that may be bloody.
- Associated chest pain and increasing dyspnea.
- Progression of Disease- As the disease
progresses, adult respiratory distress syndrome (ARDS) characterized
by refractory pulmonary edema, may occur. Signs of shock, including
hypotension and eventual multi-organ failure, may also occur.
Without early detection and treatment in less than 24 hours,
pneumonic plague is almost universally fatal.