There is often a prodrome of 1-2 days of mild headache and myalgias, followed by high fever, chills, and multiple rigors. Other pulmonary manifestations include dyspnea, pleuritic chest pain, and hemoptysis, which may be present in up to one-third of cases. Gastrointestinal symptoms include nausea, vomiting, diarrhea, and anorexia. Neurological symptoms include headache, altered mental status, and rarely, focal neurological symptoms. Musculoskeletal symptoms include arthralgias and myalgias.
Nonpulmonary symptoms are prominent early in the disease.
Absence of inflammation of the upper respiratory tract is common and is a clinically useful indicator. Chest auscultation may be normal or it may reveal rales, rhonchi, or signs of consolidation. Pericarditis and endocarditis may be present. Hepatomegaly may be seen in rare cases. The neurological examination or the patient's mental status may be abnormal.