At the first meeting with a child with fever without local symptoms, the doctor does not yet have, of course, the results of blood culture for sterility. Therefore, the doctor can choose one of three tactical options: to treat all such patients; do not treat any of them; selectively treat some of them. What are the consequences of each of these decisions?
1. Suppose a doctor decided not to treat patients with fever without local symptoms. What can this lead to? As already noted, approximately 4–5% of these children have bacteremia, of which 5–10% (depending on age and the magnitude of fever) will develop bacterial meningitis. In the same or even a higher percentage of cases, other serious bacterial infections will occur. In addition, in 50% of patients, bacteremia will still be detected by repeated blood seeding after 1–3 days. Thus, out of 300 untreated patients with a fever of unknown etiology, bacterial meningitis may develop in one child (300×0.05×0.07), and another two may experience other serious infectious diseases. If we assume that on average every 15 days a pediatrician meets one child with a fever without local symptoms, then in a year he will meet approximately 25 patients and the frequency of meningitis will be one case in 10 years! This explains the fact that practical doctors underestimate the importance of this problem. The fate of 7–8 children (300х0.05х0.5), in whom bacteremia will remain with the re-examination, is still unclear. This will be discussed below.
2. Suppose that the doctor decided to treat all patients with fever with no local symptoms with antibiotics. In this case, the frequency of meningitis and other serious bacterial infections is likely to halve. But since bacteremia is noted less than 5% of patients with fever, then 25-30 children will receive antibacterial treatment for each child with bacteremia without sufficient grounds.
3. Neither of these two solutions can be considered completely satisfactory. The third solution is to selectively treat patients selected for certain parameters, which allows treatment of a much smaller group, while at the same time not losing patients with bacteremia. To isolate a group of children (high risk, it is necessary to take into account 3 main risk factors: early age, high body temperature and an increase in the number of blood leukocytes.
With regard to age, as most authors believe, children of the first 6-24 months of life are at high risk of developing latent bacteremia. However, this is only a relative relationship. It is known that the development of pneumococcal bacteremia is characteristic for this age group. But in many works, data are given only for children in the first two years of life and exclude children between the ages of 1 and 3 months. So, Teele, McCarthy and Baron focused on patients between the ages of 3-6 and 24 months, while in other works it was clearly shown that the prevalence of latent bacteremia is not limited to only these narrow age intervals.
For example, in one McCarthy study, when observing patients with a temperature of 40 ° C and higher, the incidence of latent bacteremia was actually higher (15%) in patients aged from 36 to 48 months than in age from 3 to 18 months (12%).
We have constantly noted that the higher the body temperature, the greater the risk of developing bacteremia. Acceptable, although not indisputable, the boundary point is the body temperature of 40 ° C. For the risk of bacteremia increases sharply when the temperature rises above this level. From the above data it is obvious that as a high risk factor for the development of leukocyte bacteremia, 15×109 / l is the most suitable borderline level, both in terms of sensitivity and specificity.