A 40-year-old man presents with a dry cough and a fever for the past few days. His cough is non-productive. Today he has also had several episodes of diarrhoea and has developed bilateral pleuritic chest pain. He states that he is short of breath, most notably on exertion. He works as a Jacuzzi and whirlpool installer and smokes 15 cigarettes per day.
1. What is the most likely diagnosis?
The most likely diagnosis, in this case, is Legionnaires’ disease
The clinical features of the pneumonic form of Legionnaires’ disease include:
- Mild flu-like prodrome for 1-3 days
- Cough (usually non-productive and occurs in approximately 90%)
- Pleuritic chest pain
- Nausea, vomiting and diarrhoea
The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.
Legionella pneumophila is a Gram-negative bacterium that is found in natural water supplies and in the soil. It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.
Legionella pneumophila infections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.