[Mediastinal lymphadenopathy: Do not forget tularemia!]

Mediastinal lymphadenopathy is a common cause of referral to the pulmonologist. In addition to more frequent aetiologies such as malignancy, sarcoidosis, tuberculosis and lymphoma, unusual causes must be considered, especially in specific contexts.

We report the cases of three young patients referred to our pulmonology department for the assessment of hypermetabolic mediastinal lymphadenopathy. The context of the onset of symptoms (tick bite, contact with an infected animal) as well as paraclinical investigations (Francisella tularensis serology) made it possible to make a diagnosis of tularemia. The clinical and radiological evolution was favourable in all three cases. Tularemia is a rare but currently re-emerging infection caused by a Gram negative coccobacillus, Francisella tularensis. Human contamination occurs mainly through contact with infected animals or by tick bites. The diagnosis can be difficult because the symptoms (fever, diffuse myalgia) are non-specific, and is based on serology and an appropriate clinical context. Treatment is based on ciprofloxacin or doxycycline.

The diagnosis of tularemia must be considered in the presence of lymphadenopathy occurring after a tick bite or contact with an infected animal.