Which clinical features are commonly associated with Legionella infection?

• A. Hyponatremia and diarrhea
• B. Rash and joint pain
• C. Severe dehydration and hypoglycemia
• D. Petechial hemorrhages

Answer: (A)

Legionella infections often present as atypical pneumonia with systemic, nonpulmonary features. A common clue is hyponatremia, a low serum sodium level, which appears in a significant number of Legionella cases. Coupled with gastrointestinal symptoms such as diarrhea (often accompanied by nausea or abdominal pain), this combination is classically associated with Legionella pneumonia and helps differentiate it from other causes of pneumonia that lack prominent GI symptoms or hyponatremia.

Rash and joint pain are not typical features of Legionella infection; they point more toward other infectious or inflammatory conditions. Severe dehydration with hypoglycemia isn’t a characteristic pattern for Legionella, and petechial hemorrhages suggest other etiologies such as meningococcemia or certain vasculitic processes. Thus, hyponatremia with diarrhea best fits the common presentation of Legionella infection.