Dengue fever in Brazilian adults and children: assessment of clinical findings and their validity for diagnosis.

Although it is well known that the signs and symptoms of dengue fever (DF) may overlap with those of other diseases, few attempts have been made to assess quantitatively their validity in the diagnosis of DF. The clinical data recorded, in the Brazilian town of Uberlândia between 1993 and 1998, on the notification forms from 495 serologically confirmed cases of DF and 650 patients who tested negative for this disease were therefore compared. Fever, headache, myalgia, retro-orbital pain and arthralgia were the most commonly reported symptoms among the confirmed cases (each occurring in at least 92% of the cases), whereas haemorrhagic manifestations (reported in 7% of cases) were uncommon. Although comparisons between the two groups gave risk ratios (RR) very close to 1 for most signs and symptoms, rash [RR=1.86; 95% confidence interval (CI)=1.63-2.13] and petechiae (RR=1.38; CI=1.07-1.79) were more commonly found among the confirmed cases. As the positive and negative predictive values of all of the signs and symptoms investigated were low, diagnosis of DF should not be based solely on clinical grounds.

Hantavirus pulmonary syndrome in Brazil: clinical aspects of three new cases.

Hantavirus pulmonary syndrome (HPS) has been recognized recently in Brazil, where 28 cases have been reported as of September 1999. We report here the clinical and laboratory findings of three cases whose diagnoses were confirmed serologically. All the patients were adults who presented a febrile illness with respiratory symptoms that progressed to respiratory failure that required artificial ventilation in two of them. Laboratory findings were most of the time consistent with those reported in the United States in patients infected with the Sin Nombre virus, and included elevated hematocrit and thrombocytopenia; presence of atypical lymphocytes was observed in one patient. The chest radiological findings observed in all the patients were bilateral, diffuse, reticulonodular infiltrates. Two patients died. Histopathological examination of the lungs of these patients revealed interstitial and alveolar edema, alveolar hemorrhage, and mild interstitial pneumonia characterized by infiltrate of immunoblasts and mononuclear cells. In the epidemiologic investigation of one of the cases, serologic (ELISA) tests were positive in 3 (25%) out of 12 individuals who shared the same environmental exposure. HPS should be included in the differential diagnosis of interstitial pneumonia progressing to acute respiratory failure.

Probability of occurrence of life-threatening ventricular arrhythmias in Chagas' disease versus non-Chagas' disease.

The implantable cardioverter defibrillator (ICD) is highly effective in the treatment of ventricular arrhythmias (VA) responsible for sudden cardiac death. However, the probability of occurrence of these arrhythmic events in presence of cardiomyopathy remains uncertain. The aim of this study was to compare the probability of nonoccurrence of life-threatening VA in ICD recipients with Chagas' versus non-Chagas' heart disease. Over a mean follow-up of 10.5 months, 53 ICD recipients (mean age = 50.1 years, 48 male) were evaluated. Eleven patients had Chagas' heart disease, 19 had idiopathic dilated cardiomyopathy and 23 had ischemic cardiomyopathy. Ventricular tachyarrhythmias with a cycle length < 315 ms were considered life-threatening. The cumulative probability of nonoccurrence of life-threatening VA was examined by Kaplan-Meyer method and the outcomes were submitted to the log rank test. At 2 years, the cumulative probability of life-threatening VA nonoccurrence was 0 in the Chagas' heart disease group versus 40% up to 55 months of follow-up in the non-Chagas' disease group (P = 0.0097). Among patients with cardiomyopathies of different etiologies, those with Chagas' heart disease had the lowest cumulative probability of nonoccurrence of life-threatening VA, confirming its unfavorable prognosis and the importance of preventive measures against sudden death in this disease.