- high fever, > 40 Celsius, with relative bradycardia
- gastrointestinal symptoms (nausea, vomiting, diarrhea) accompanying pneumonia
- lethargy
- headache
- labs: hyponatremia, renal and hepatic dysfunction
Empiric treatment for pneumonia (newer macrolides and respiratory tract qunolones) kill this bacteria .... so why care about diagnosing this antigen specifically? I don't know ... perhaps this info will make you sound smart when talking to the PCP.
Source
Pedro-Botet, Luisa, MD PhD. "Clinical manifestations and diagnosis of Legionella infection." Up to Date. 1 May 2008.