Legionella pneumonia

Vignette says a 65 year old male with a history of chronic obstructive pulmonary disease presents to the pulmonology clinic with chief complaints of fever, cough and shortness of breath over the past few days; He also reports of fatigue, malaise, myalgias, headache and diarrhea over the past few days; He had recently completed his cruise ship travel prior to the appearance of above mentioned complaints; Vital signs show blood pressure of 110/70 mm of Hg, pulse rate of 58 bpm, respiratory rate of 18 breaths/min, oxygen saturation of 92% in RA and temperature of 101.2 F; CBC shows leukocytosis, RFT shows hyponatremia and LFT shows elevated AST & ALT; Urinary legionella antigen test is positive; Chest x-ray shows diffuse infiltrates; Diagnosis?

Diagnosis is Legionella pneumonia.

Presents with fever, cough, shortness of breath, myalgias, headache, and diarrhea; Classically acquired via aerosols.

Risk factors include older age, smoking, chronic lung disease and immunocompromised states.

Etiologies:-
1. Recent travel (e.g. hotels, cruise ships).
2. Exposure to contaminated water sources (air conditioning, hot tubs and fountains).

Diagnosis:-
1. Urine antigen test for the detection of Legionella antigen.
2. Sputum culture with BCYE agar shows Legionella growth.
3. CBC shows leukocytosis, RFT shows hyponatremia and LFT shows elevated AST & ALT.
4. Chest x-ray shows unilateral or bilateral patchy or diffuse infiltrates.

Management:-
1. Outpatient management is azithromycin or respiratory fluoroquinolone (i.e. levofloxacin).
2. Inpatient management is ceftriaxone and azithromycin.