Pulmonary tularaemia: a differential diagnosis to lung cancer

Abstract

BackgroundPulmonary manifestations of tularaemia are reported to be infrequent in previous publications. During 2016, we noticed an increase in the number of hospitalised patients with pulmonary tularaemia in Eastern Norway. We aimed to investigate primary pulmonary tularaemia in Eastern Norway in terms of symptoms, radiological and microbiological findings, incidence and risk exposure.MethodsA retrospective analysis of consecutive primary pulmonary tularaemia cases from 2016 until 2018 was conducted.ResultsFrom 1 September, 2016 until 31 December, 2018, 22 patients were diagnosed with primary pulmonary tularaemia at Innlandet Hospital Trust, representing 48% of all reported tularaemia cases in the region. A peak annual incidence of 3.4 in 100 000 was found in 2017.All 22 patients lived in, or had recently visited, rural areas. Eighteen patients reported risk exposure for tularaemia, such as wood chopping, outdoor activities and farming prior to symptom onset. All patients experienced fever, and 19 patients had respiratory symptoms. Ten patients were in spontaneous recovery at diagnosis.All patients had a chest computed tomography scan. Overall, 19 patients had pulmonary lesions and 18 had enlarged intrathoracic lymph nodes. The computed tomography images were described as suspicious of malignancy in 17 patients.ConclusionPulmonary manifestations in tularaemia occurred more frequently in our region than expected from previous reports. Although all patients had symptoms consistent with infection, the majority were primarily investigated considering lung cancer due to the radiology report. In endemic areas, pulmonary tularaemia may be an important differential diagnosis to lung cancer.

Targeting Tularemia: Clinical, Laboratory, and Treatment Outcomes From an 11-year Retrospective Observational Cohort in Northern Sweden

“…Our cohort had similar demographics to previous studies performed in northern Europe [ 3 , 9 , 11 , 28–31 ] and identified men and women aged 40 to 60 years as having the highest burden of tularemia, although there was high prevalence of infection throughout all age groups. Our data support ulceroglandular tularemia transmitted by mosquitos as the predominant clinical form in this geographical region [ 6 , 31 ], pulmonary tularemia as an important cause of pneumonia, and atypical disease often misdiagnosed as malignancy and/or tuberculosis [ 9 , 32 ]. Immunosuppression was infrequent in our cohort (n = 8), with 4 cases admitted to the hospital, including 1 developing pulmonary tularemia and 2 cases with F. tularensis septicemia.…”

Tularaemia – a diagnostic challenge

“…According to Kravdal et al, the most common routes of bacteria transmission are wood chopping, farming, carpentry, hunting, and other outdoor activities [49]. Most of the patients in this study became infected in the autumn.…”

“…Most cases present as subacute or chronic infections with relatively non-specific symptoms, including fever, cough, chest pain, and dyspnea. Radiological findings include hilar adenopathy, suggesting tuberculosis or non-infectious diseases (e.g., lymphoma, lung cancer, and sarcoidosis), lobar or multi-lobar infiltrates, and pleural effusion [41,49]. Most commonly, enlarged mediastinal or hilar lymph nodes and pulmonary lesions are found on the chest CT.…”

Identification ofFrancisella tularensisin ascites in the context of typhoidal tularaemia

“…Hence, the seasonal increase in the incidence of tularaemia also correlates with tick bites 11 22. Infections by domestic animals through scratches or bites or the aerosolisation of rodents’ carcasses or excrements through activities such as lawn mowing, gardening or house renovations have been reported 17 23–26…”