These symptoms, along with a low-grade fever, can last several months if not initially diagnosed correctly.

General lethargy, weakness, muscle aches, headache, and low-grade fever may occur.

The signs and symptoms are similar to a common cold: runny nose, sneezing, mild cough, and low-grade fever.

Vital signs may disclose low-grade fever, tachypnea, tachycardia, and hypotension.

Pneumonia, for example, may present with low-grade fever and confusion, rather than the high fever and cough seen in younger people.