J Pediatric Infect Dis Soc. 2023 Jul 19:piad051. doi: 10.1093/jpids/piad051. Online ahead of print.
ABSTRACT
BACKGROUND: Tick-borne diseases have grown in incidence over recent decades. As a result, diagnostic testing has become more common, often performed as broad antibody-based panels for multiple tick-transmitted pathogens. Rocky Mountain spotted fever (RMSF) is rare in our region yet may cause severe morbidity, leading to diagnostic screening in low-risk patients. We sought to describe trends in RMSF diagnostic testing, rate of IgG seropositivity, and clinical features of those tested.
METHODS: We performed a retrospective chart review of patients ≤ 21 years old undergoing testing for RMSF and/or with an ICD-9/10 code for RMSF. Patients were categorized by infection likelihood based on clinical and laboratory criteria adapted from CDC’s case definition of spotted fever rickettsioses. Clinical data were collected and analyzed with descriptive statistics.
RESULTS: 170 patients were included. 5.8% met CDC criteria for rickettsial infection, 6.5% had an elevated IgG titer but lacked suggestive symptoms, and 87.6% had a negative IgG titer. Many patients tested were unlikely to have RMSF, including 50% lacking fever, 20% lacking any RMSF ‘classic triad’ symptoms, 13% without acute illness, and 22% tested during months with low tick activity. Convalescent serology was performed in 7.6% of patients and none underwent R. rickettsii PCR testing.
CONCLUSIONS: Diagnostic testing was frequently performed in patients unlikely to have RMSF. We identified many opportunities for improving test utilization. Reserving testing for those with higher pre-test probability, performing convalescent serology, and utilizing PCR may improve accuracy of RMSF diagnosis and reduce clinical challenges stemming from inappropriate testing.
PMID:37467350 | DOI:10.1093/jpids/piad051
