The Tick-Borne Infections in Children Study Group reviewed 92 patients from six hospitals in the southeastern and south-central US treated from 1990 to 2002 for Rocky Mountain spotted fever (RMSF) in order to identify clinical findings associated with death or neurologic deficits at the time of hospital discharge. Patients in the study met established criteria for confirmed or probable RMSF.1,2 Children (median age 5.8 years; range 3.7–9.1) presented to the hospitals a median of six days after the onset of symptoms, most commonly fever (98%), rash (97% [62% petechial]), nausea or vomiting (73%), and headache (61%). Less common symptoms included altered mental status (33%), photophobia (18%), seizures (17%), and coma (10%). Ninety percent of cases occurred between the months of April through August.
Only 49% of children with RMSF reported history of a tick bite. Onset of rash occurred on the first day of symptoms for 83 (90%) children, and 91 (99%) children sought medical care by day 2 of illness. The classic symptoms and physical findings associated with RMSF were frequently absent at the time of hospital presentation: 58% of children had fever, rash, and headache, but only 45% had fever, rash, and a history of a tick attachment. Initial hospital laboratory tests showed that 59% of patients had a platelet count <15 x 100,000/mm3 and 52% had a depressed serum sodium (<135 meq/dl). Among 38 children who underwent a lumbar puncture, the median leukocyte count in the cerebrospinal fluid (CSF) was 25 with a range of 3–38 cells/mm3, and no child had low CSF glucose.
Although 86% of hospitalized patients had previously sought medical care, only four received anti-rickettsial therapy prior to hospital admission. Three children died and 13 had neurologic impairment at the time of hospital discharge. Two patients experienced digital necrosis. All patients who died or had neurologic impairment were critically ill. Coma, need for vasoactive medications, and fluid resuscitation were independently and significantly associated with increased risk of death or neurologic disability. The authors concluded that RMSF is difficult to diagnose based on laboratory and clinical symptoms and that clinical suspicion must remain high during the spring and summer months.
Dr. Bratton has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of a commercial product/device. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.
Despite the availability of low-cost and effective antibiotic therapy, preferably doxycycline, RMSF continues to cause severe illness and death in otherwise healthy children. The greatest challenge is diagnosing this infection early when antibiotic therapy is most effective.3,4 The majority of patients with RMSF in this series sought medical care within two days of symptoms. However, early signs and symptoms of RMSF are nonspecific, making diagnosis difficult....