Legionnaires Disease


Step 1: View clinicals

A 28 year old man presents with fever with chills, a non-productive cough, dyspnea upon minimal exertion, and intermittent watery diarrhea with abdominal pain for 5 days. He was treated with Amoxicillin for 4 days but showed no sign of improvement, despite good compliance. His medical, surgical and travel histories are unremarkable. He does not smoke, and only consumes alcohol in moderation. There is no history of recreational drug abuse. A complete blood count is significant for a leukocytosis of 16,800/mm3.

Step 2: Order all relevant investigations

Bronchoalveolar Lavage

Gram stain of aliquots: a few mononuclear leukocytes, with several rod shaped organisms. Culture results will be available in 48 to 72 hours.

Chest X-Ray

There are bilateral patchy basal infiltrates, more prominent on the right side.

Serum Electrolytes

Sodium: 131 mmol/L (135-145) Potassium: 4.6 mmol/L (3.5-5.5) Chloride: 107 mmol/L (95-110) Phosphate: 0.66 mmol/L (0.81-1.45)

UAT for Legionella & Pneumococcus

Urinary Antigen Testing (UAT): positive for Legionella pneumophila,

Step 3: Select appropriate management

Supplemental Oxygen
Cefoperazone + Sulbactam
ICU Care

Score: ★★☆