Human Monocytic Ehrlichiosis in Children
Human Monocytic Ehrlichiosis in Children
Background: Human monocytic ehrlichiosis (HME) is a tick-borne illness caused by Ehrlichia chaffeensis. Data about disease in children have been largely derived from case reports or small case series.
Methods: A retrospective review of all medical and laboratory records from 6 sites located in the tick belt of the Southeastern United States was carried out. Demographic, history and laboratory data were abstracted from the identified medical records of patients. Bivariate statistical comparisons were performed using Fisher exact test or Wilcoxon rank sum tests.
Results: Common clinical signs and symptoms of patients with HME (n = 32) included fever (100%), headache (69%), myalgia (69%), rash (66%), nausea/vomiting (56%), altered mental status (50%) and lymphadenopathy (47%). Only 48% had a complaint of fever, headache and rash. Common laboratory abnormalities included thrombocytopenia (94%), elevated aspartate aminotransferase (90%), elevated alanine aminotransferase (74%), hypoalbuminemia (65%), lymphopenia (57%), leukopenia (56%) and hyponatremia (55%). The median number of days of illness before the initiation of antirickettsial therapy was 6. Patients who received sulfonamides before starting doxycycline therapy developed a rash, were admitted to the hospital, and started doxycycline at a later date. Twenty-two percent of patients were admitted to the intensive care unit with 12.5% of patients requiring ventilatory and blood pressure support.
Conclusions: Although HME has been recognized among children for almost 20 years, there is only a limited knowledge about its clinical course. Even among physicians practicing in endemic regions, few cases are diagnosed each year. More work is needed to understand the true burden of disease and the natural history among asymptomatically and symptomatically infected children.
Human monocytic ehrlichiosis (HME) is a tick-borne illness caused by Ehrlichia chaffeensis. The distribution of this rickettsial disease parallels that of its major tick vectors, the Lone Star tick (Amblyomma americanum) and the American dog tick (Dermacentor variabilis). HME became a reportable disease in the United States in 1999. During the past 6 years, a mean of 196 cases per year (range 99-321 cases) have been reported to the Centers for Disease Control and Prevention. Of these, 53% occurred in Missouri, Kentucky, Tennessee, North Carolina and Arkansas. Most human disease is reported in the spring and summer (April-September), which correlates with the time of highest tick activity.
HME in children caused by E. chaffeensis was first reported by Edwards et al. Although there have been several review articles describing HME in children, these data have been largely derived from case reports or small case series. Infection with ehrlichia in children, however, may be more common than what is recognized through disease reporting. A recent cross-sectional serosurvey of 1999 children (ages 1-17 years) from the Southeast and South-Central regions of the United States by the TICS Group demonstrated that 3.1% of children had E. chaffeensis antibody titers of 160 or higher. This suggests that many ehrlichia infections are asymptomatic or unrecognized and/or perhaps misdiagnosed as a viral illness.
The objective of the current study was to better describe the clinical spectrum of symptomatic HME encountered at medical centers treating children in endemic areas.
Background: Human monocytic ehrlichiosis (HME) is a tick-borne illness caused by Ehrlichia chaffeensis. Data about disease in children have been largely derived from case reports or small case series.
Methods: A retrospective review of all medical and laboratory records from 6 sites located in the tick belt of the Southeastern United States was carried out. Demographic, history and laboratory data were abstracted from the identified medical records of patients. Bivariate statistical comparisons were performed using Fisher exact test or Wilcoxon rank sum tests.
Results: Common clinical signs and symptoms of patients with HME (n = 32) included fever (100%), headache (69%), myalgia (69%), rash (66%), nausea/vomiting (56%), altered mental status (50%) and lymphadenopathy (47%). Only 48% had a complaint of fever, headache and rash. Common laboratory abnormalities included thrombocytopenia (94%), elevated aspartate aminotransferase (90%), elevated alanine aminotransferase (74%), hypoalbuminemia (65%), lymphopenia (57%), leukopenia (56%) and hyponatremia (55%). The median number of days of illness before the initiation of antirickettsial therapy was 6. Patients who received sulfonamides before starting doxycycline therapy developed a rash, were admitted to the hospital, and started doxycycline at a later date. Twenty-two percent of patients were admitted to the intensive care unit with 12.5% of patients requiring ventilatory and blood pressure support.
Conclusions: Although HME has been recognized among children for almost 20 years, there is only a limited knowledge about its clinical course. Even among physicians practicing in endemic regions, few cases are diagnosed each year. More work is needed to understand the true burden of disease and the natural history among asymptomatically and symptomatically infected children.
Human monocytic ehrlichiosis (HME) is a tick-borne illness caused by Ehrlichia chaffeensis. The distribution of this rickettsial disease parallels that of its major tick vectors, the Lone Star tick (Amblyomma americanum) and the American dog tick (Dermacentor variabilis). HME became a reportable disease in the United States in 1999. During the past 6 years, a mean of 196 cases per year (range 99-321 cases) have been reported to the Centers for Disease Control and Prevention. Of these, 53% occurred in Missouri, Kentucky, Tennessee, North Carolina and Arkansas. Most human disease is reported in the spring and summer (April-September), which correlates with the time of highest tick activity.
HME in children caused by E. chaffeensis was first reported by Edwards et al. Although there have been several review articles describing HME in children, these data have been largely derived from case reports or small case series. Infection with ehrlichia in children, however, may be more common than what is recognized through disease reporting. A recent cross-sectional serosurvey of 1999 children (ages 1-17 years) from the Southeast and South-Central regions of the United States by the TICS Group demonstrated that 3.1% of children had E. chaffeensis antibody titers of 160 or higher. This suggests that many ehrlichia infections are asymptomatic or unrecognized and/or perhaps misdiagnosed as a viral illness.
The objective of the current study was to better describe the clinical spectrum of symptomatic HME encountered at medical centers treating children in endemic areas.
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