How to diagnose mediterranean spotted fever in patients with fever and rash: a prospective study

Abstract

Background: Mediterranean spotted fever (MSF) has a high incidence in Portugal, especially in the Alentejo region, where its mortality can reach 4.5%. Although diagnosis is clinical, the predictive
value of the associated signs and symptoms is unknown.
Objectives: To identify clinical and laboratory features, possible
to obtain in the Emergency Room, that correlate with a diagnosis
of MSF, in patients with fever and rash.
Methods: A prospective study was conducted, between 1st
January and 31st December 2002, that included all patients
admitted with fever and rash. A clinical and laboratory evaluation
was performed, along with serological screening for Rickettsiae,
Borreliae, Ehrlichiae, Epstein Barr, HIV, Echo, Coxsackie, Salmonellae, Leptospirae, Treponema, Rheumatic fever, endocarditis and
lupus. The correlation between the clinical and laboratory data
and a definitive diagnosis of Rickettsiosis was studied using the
Chi-square (or Fisher, when necessary) test. Logistic regression
was used to study the predictive value of the variables with a
statistically significant correlation.
Results: 55 patients where admitted with fever and rash, in
whom MSF was confirmed in 44. The mean age was 60.7 years
and 46.7% were male. Only an admission diagnosis of MSF had
a statistically significant correlation with that same definitive
diagnosis (p=0.008).
Conclusions: In this study, only an admission diagnosis of MSF
had a statistically significant correlation with that same definitive
diagnosis (odds ratio 10.7). The week of admission had a weak
statistical significance (p=0.049, and odds ratio 4.0).