Revista Portuguesa de Pneumologia Revista Portuguesa de Pneumologia
Rev Port Pneumol 2017;23:117-23 - Vol. 23 Num.3 DOI: 10.1016/j.rppnen.2017.01.007
Original article
The typical presentation of an atypical pathogen during an outbreak of Legionnaires’ disease in Vila Franca de Xira, Portugal, 2014
A. Diasa,, , A. Cysneirosa, F.T. Lopesa, B. von Amanna, C. Costaa, P. Dionísioa, J. Carvalhoa, V. Durãoa, G. Carvalhob, F. Paulaa,c, M. Serradoa, B. Nunesd,e, T. Marquesf, F. Froesa,c,, , C. Bárbaraa,g
a Chest Department, Centro Hospitalar Lisboa Norte, Lisboa, Portugal
b Internal Medicine Department, Hospital de Cascais Dr. José de Almeida, Cascais, Portugal
c Intensive Care Unit, Chest Department, Centro Hospitalar Lisboa Norte, Lisboa, Portugal
d Epidemiology Department, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa, Portugal
e Center for Research in Public Health, Escola Nacional de Saúde Pública, Universidade NOVA de Lisboa, Lisboa, Portugal
f Consultant of Directorate-General of Health, Portugal
g Institute of Environmental Health (ISAMB), Faculty of Medicine, University of Lisbon, Lisboa, Portugal
Received 28 November 2016, Accepted 23 January 2017
Abstract
Background

An outbreak of Legionella pneumophila serogroup 1, with 403 cases was identified on the 7th November 2014 in Vila Franca de Xira, Portugal. Outbreak source was the wet cooling system of a local factory. Hospital Pulido Valente was one of the hospitals receiving patients with Legionnaires’ disease (LD).

Methods

We describe the clinical findings and diagnostic methods used among the 43 confirmed or probable cases admitted to our department.

Results

60.5% were male, mean age was 56.1±13.5 years and tobacco smoking was the most frequent risk factor (76.7%). All patients had fever, 62.8% ≥39.5°C, 72.1% had chills and myalgia/arthralgia and 62.8% had dry cough. Extra pulmonary symptoms were frequent: confusion and headache occurred in 34.9% and gastrointestinal symptoms in 20.9%.

High C-Reactive Protein (55.8% ≥30mg/dL) and hyponatremia (62.8%) were the laboratorial abnormalities most commonly found. Hypoxemia occurred in 55.8% and hypocapnia in 93%. Urinary Antigen Test (UAT) was positive in 83.7% of the cases.

Conclusions

Although not specific, a combination of risk factors, symptoms and laboratory findings can be highly suggestive of LD, even in an outbreak. This should prompt diagnosis confirmation. Routine use of UAT in less severe cases of community acquired pneumonia might contribute to earlier diagnosis.

Keywords
Legionnaires’ disease, Outbreak, Clinical presentation
Rev Port Pneumol 2017;23:117-23 - Vol. 23 Num.3 DOI: 10.1016/j.rppnen.2017.01.007