Institutional members access full text with Ovid®

Share this article on:

Clinical Profile and Predictors of Fatal Rocky Mountain Spotted Fever in Children from Sonora, Mexico

Alvarez-Hernandez, Gerardo MD, PhD*; Murillo-Benitez, Coral MD; del Carmen Candia-Plata, Maria MD, PhD*; Moro, Manuel DVM, PhD

Pediatric Infectious Disease Journal: February 2015 - Volume 34 - Issue 2 - p 125–130
doi: 10.1097/INF.0000000000000496
Original Studies

Background: Rocky Mountain spotted fever (RMSF) is an increasingly important cause of preventable mortality in children in Sonora, Mexico. Although early treatment with tetracycline has shown to prevent fatal outcome, the disease remains a life-threatening condition, particularly for children. This study describes the clinical factors associated with pediatric mortality due to RMSF in Sonora, in order to guide healthcare practices.

Methods: This is a retrospective analysis of 104 children consecutively hospitalized at the major pediatric hospital of Sonora, diagnosed with RMSF between January 2004 and December 2013. Descriptive statistics and multiple logistic regression were used to identify risk factors for fatal outcome.

Results: The case fatality ratio in this cohort was 20.2%. Children were hospitalized after a median of 6 days from onset of symptoms including fever (100%), rash involving palms and soles (88.5%) and headache (79.8%); 90.4% of fatal cases had low platelet counts (<50,000/μL) and 33.3% showed serum creatinine concentrations above the normal value. Acute kidney injury increased mortality, odds ratio (ORadj) = 4.84, 95% confidence interval (CI): 1.2–16.2, as well as delay in treatment (≥ 5th day from onset) with doxycycline, ORadj = 2.62, 95% CI: 1.24–5.52 and hemorrhage, ORadj = 6.11, 95% CI: 1.89–19.69.

Conclusions: RMSF is a public health problem in Sonora. Clinically, fatal cases differ from non-fatal cases in renal function and hemorrhagic manifestations, although these findings may occur too late for a timely intervention. First-line providers must be educated to harbor a timely suspicion of RMSF, and should provide empiric treatment with doxycycline when febrile patients first present for care.

From the *Department of Medicine and Health Sciences, Universidad de Sonora, Hermosillo, Mexico; School of Medicine and Health Sciences, Instituto Tecnológico y de Estudios Superiores de Monterrey, Monterrey, Mexico; and Division of Comparative Medicine, Office of Research Infrastructure Programs, National Institutes of Health, Bethesda, Maryland.

Accepted for publication July 24, 2014.

The authors have no funding or conflicts of interest to disclose.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (

Address for correspondence: Gerardo Alvarez-Hernandez, MD, PhD, Department of Medicine and Health Sciences, Universidad de Sonora, Blvd. Luis D. Colosio SN, col. Centro. Hermosillo, Sonora, CP 83000, Mexico. E-mail:

Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.