About 1/3 patients have a history of upper respiratory tract infection before diagnosis of pneumonia. Natural course is of 7-10 days.
In adults, the symptoms are usually high fever, cough, chest pain, dyspnea. I'll explain more.
1. Chills, high fever
Typical symptoms are sudden chills, high fever, body temperature over 102 degree, accompanied by headaches, muscle limp. After antibiotics treatment the fever becomes Atypical, the elderly people might carry low fever or no fever.
2. Cough, expectoration
In early stage it's more of irritated dry cough, then followed by a white mucus phlegm or capillary sputum, in 1-2 days, it can develop to mucus-bloody phlegm, rust-colored phlegm, pus phlegm.
3. Chest Pain
The chest pain is often severe, like being needled, and the pain gets aggravated with cough or deep breathing. Sometimes the pain can radiate to shoulder or abdomen. Lower lobe pneumonia may induce abdominal pain from the pleura, which can be misdiagnosed as acute abdomen.
Cyanosis, chest pain and dyspnea are caused by the deficiency of ventilation, gas exchange disorder and arterial oxygen saturation.
5. Other Symptoms
A few patients have nausea, vomiting, abdominal distension or diarrhea and other gastrointestinal symptoms, severe disease can appear delirious, irritability, drowsiness, coma and so on.