Case Studies
A Boy, a Bug, and a Bite
A Toddler with an Inflamed Lesion
By Julie K. Anderson, M.D.
A 26-month-old boy was brought to our clinic last summer with a 3-day history of high fever, vomiting, and anorexia. Before that, he had been very healthy with no medical problems and no prior surgeries. He had been seen a few weeks before in clinic with what appeared to be deer fly or mosquito bites. The family lives near the Mississippi River and spends a lot of time outdoors.
The parents noticed no upper respiratory symptoms associated with the boy’s fever. His last bowel movement was 2 days prior, but he had not eaten much. The parents had noticed some swelling in his groin that seemed painful. On examination, the boy appeared ill and dehydrated; his temperature was 103.1 degrees F. His head, ears, eyes, nose, and throat and neurological exams were normal. The boy’s abdomen was extremely tender and difficult to assess, except for a significantly tender mass in his left groin. Testicles were descended and were not tender. His left leg had a small, pustular lesion that was inflamed; other red papules on the legs were consistent with insect bites. The pustule was cultured; no tick or stinger was visible.
The results of lab tests are as follows: WBC 14.7, CRP 4.24, UA negative. Abdominal X-ray showed an ileus pattern. A CT scan of the abdomen and pelvis was significant for lymphadenopathy in the left groin. The child was admitted to the hospital for hydration and placed on Rocephin for what was presumed to be a reactive lymphadenopathy from an infected bug bite. His fever subsided after day 2 of antibiotics. He was discharged from the hospital on day 5 on Augmentin and was doing well except for persistent lymphadenopathy in the groin. The blood cultures that were taken on admission were negative; however, the wound culture initially showed possible Haemophilus influenzae, so it was sent on for further evaluation. Also negative were Lyme titer, urine culture, and herpes culture. The following week, the boy’s wound culture was positive for Francisella tularensis. He was subsequently readmitted for treatment with a 1-week course of gentamycin and is now doing well with no adverse sequelae.
Tularemia is quite rare in Minnesota but is believed to be underdiagnosed. Unfortunately, few epidemiologic studies have been done. Since 1994, just 6 cases, including this one, have been reported in the state. Most cases are caused by a bite from an infected animal, handling dead animals, or a bite from a vector such as a deer fly or tick. Four of the 6 cases have been in older persons (ages 48 to 72). The other was in a 4-year-old, who is the only other patient whose disease has been attributed to a tick or deer fly bite.1 Nationally, about 200 cases are reported each year in the United States. Most occur in the rural areas of south-central and western states.2
Francisella tularensis is highly infectious and at one time was fatal in 33% of cases. A small number of organisms (10 to 50) can cause the disease. Symptoms usually appear 3 to 5 days after exposure to the bacteria but can take as long as 14 days to manifest. It is considered a reportable disease as well as a potential bioterrorism agent by the CDC. If it were used as a weapon, the bacteria would likely be made airborne for exposure by inhalation.2
Tularemia may be rare in Minnesota, but cases such as this one underscore the need for us to consider it when an ill patient presents with an insect bite.
Julie Anderson is a family physician at the St. Cloud Medical Group.
References
1. Minnesota Department of Health, Infectious Disease Epidemiology, Prevention and Control Division.
2. Dennis DT, Inglesby TV, Henderson DA, et al. Tularemia as a biological weapon: medical and public health management. JAMA. 2002:285(21);2763-73.