Legionella masquerade

We discussed a 69yo M with HIV (CD4 230, not on HAART), HCV admitted for non specific symptoms of primarily RUQ and midepigastric dull abd pain with malaise, decreased PO, dry cough for 3 days. Initial though process on presentation was GI pathology but CXR showed RLL PNA. Team sent out Legionella urine Ag which came back positive. After treatment with azithromycin, symptoms improved and patient was eventually discharged.

Teaching points:

– RLL PNA can often present with GI complaints, so expand your differential diagnoses to include lung processes as well

– more severe Legionnare’s disease seen with HIV and other cell mediated immunity compromise conditions. This is because Legionella maintains it’s lifecycle intracellularly and multiplies profusely if cell mediated immunity is compromised

– urine Legionella Ag test is very sensitive and specific. Although it tests only for serotypeI, is still good because 95% of CAP from legionella is caused by serotypeI

– important to identify and treat with macrolides or fluoroquinolones

Articles referenced: Legionnare’s disease and HIV and Legionella- 25 years investigation