Community-acquired pneumonia in adults with Down syndrome. Three clinical cases and a review of the literature

John Langdon Down first described this genetic disorder known today as Down syndrome (DS), due to a trisomy of chromosome 21. The frequent appearance of respiratory infections in DS is attributed to structural and functional anomalies of the respiratory system, the presence of congenital heart malformations and IgG deficits. We present three clinical cases of adult DS patients with community-acquired pneumonia, and a review of the literature regarding: epidemiology, prevalence, symptomatology, laboratory and radiographic findings, morbidity, mortality, clinical evolution and the importance of prevention of pneumonia in DS patients. These patients presented symptoms of acute infection of the lower respiratory tract: high fever, scanty productive cough with or without sputum, pleuritic chest pain, dyspnea, fatigue, myalgia, and other atypical symptoms. Chest radiography showed focal inflammatory condensation in the affected lung and bilateral alveolo-interstitial infiltrate. Laboratory tests showed increased values of leukocytes and C-reactive protein, deficiency of IgG and low lymphocyte CD4+. Patients with DS are highly susceptible to lower and higher respiratory tract infection. Community physicians should take exceptional precautions on detecting respiratory symptoms in these patients, since they may result in pneumonia and bronchopneumonia. Presentation may be atypical and the complications may even lead to mortality.