[Clinical criteria to diagnose dengue in its early stages]

Clinical differentiation of dengue from other diseases with similar symptoms is difficult. The case definition of the World Health Organization (WHO) has high sensitivity but its specificity is very low.

A diagnostic scale was formulated for early clinical diagnosis of dengue that provided greater accuracy than that of the WHO definition.

A cohort of 251 adults (> 12 years of age) with unspecific acute febrile syndrome was selected from clinics located in Bucaramanga, Colombia. They consisted of 125 cases of dengue (serologically and/or virologically confirmed) and 126 with other febrile diseases. Clinical manifestations encountered during the first four days of dengue disease were determined, along with the diverse diagnostic combinations that were presented.

: The scale consisted of the following criteria: presence of rash, positive tourniquet test, absence of nasal discharge, arthralgias, absence of diarrhea (1 point for each finding), leukocyte count < 4,000/mm3 (3 points) and platelet count < 180.000/mm3 (2 points). In a receiver-operating-characteristic curve, the predictive area of 81.0% was significantly superior to the one produced with WHO criteria, (70.0%, p < 0.001). Febrile syndrome with at least a 3 point score obtained the following values: sensitivity = 95.2%; specificity = 27.8%; positive predictive value = 56.7%; negative predicative value = 85.4%. With a 6-point score, sensitivity = 70.4%; specificity = 78.6%; positive predictive value = 76.5%; negative predicative value = 72.8%. With at least 8 points: sensitivity = 42.4%; specificity = 96%; positive predictive value = 91.4%; negative predictive value = 62.7%. With 9 or 10 points, specificity and positive predictive value were of 100%.

The described scale proved useful for early clinical diagnosis of dengue, but requires validation for its application in endemic areas.