© Borgis - New Medicine 3/1999, s. 24-25
Michał Grzegorowski, Jarosław Antyborzec, Jarosław Szydłowski
NBT test in children with subglottic laryngitis
Department of Pediatric Otolaryngology, Institute of Pediatrics, Medical Academy, Poznań
Head: Prof. Michał Grzegorowski, M.D.
In 1968 Park and co-workers introduced the NBT test which was used in recognition of bacterial infection. Subglottic laryngitis (SL) is caused by viruses, but in the second stage of this disease bacterial infection may occur.
The aim of this study is assesment of the value of the NBT test in children with SL before and after treatment.
Examination of the values given by the NBT test were performed twice in 60 children with SL and once in 26 children as the control group. We observed a statistical difference between the results of the test in children with SL by admission and after 57 days of treatment.
According to the results of the test in children under 3 years of age, especially in a severe case of SL, antibiotic treatment is recommended.
In 1968 Park and co-workers introduced a spontaneous test for reducing nitroblue tetrazolium, which was used for recognition of bacterial infections (7). The NBT test concept is based on the hypothesis that a metabolic change and an increased reduction of nitroblue tetrazolium dye would take place when leukocytes are involved in phagocytosis in vivo during a natural infection. A significant increase in test values was observed not only in bacterial diseases such as bacterial meningitis, bacterial endocarditis, osteomyelitis, peritonitis, pneumonia etc., but also in malaria, miliar tuberculosis, chronic granulomatous disease, and in the newborn (3, 8). Some authors reported that the level of this test is higher in neoplasms (6, 9).
The etiology of subglottic laryngitis (SL) is not homogenous (1, 2). It is thought that viruses are the direct cause. In the second stage of the illness bacterial infection may be found (4).
The aim of this work is the estimation of the values of the NBT test in children with subglottic laryngitis, before and after treatment, and comparison with the results obtained from children in a control group.
Material and method
In 60 children with SL aged 18 months to 10 years double examinations of the values of the NBT test were performed.
The first examination was performed at 8.00 a.m., on the day of admission to the clinic. The second was performed on the 5-7th day of treatment at the same time. Children with SL were divided into 2 groups. In the younger group there were 31 children up to 3 years of age, and in the older group 29 children. Twenty-six children of the control group never had SL and were healthy during the examination.
The NBT test was performed according to the Park and co-workers method. Blood for examination was placed in plastic test tubes. After staining the smears were examined under a light microscope and 100 neutrophiles were counted. Only those with a large black deposit were considered to be NBT positive. Statistical analysis was performed by the Willcoxon and Mann Whitney test.
The results of the NBT testing after admission, in examinations performed on children with SL in both older and younger groups did not differ from the value from the test in children from the control group (Table 1).
Table 1. Results of nbt-test depending on age (%).
|Group||Before treatment (A)||5-7 days after treatment (B)||Statistical difference (A/B)|
|Younger (n = 31)||12.9 ± 7.4||23.2 ± 13.2||p <0.05|
|Older (n = 29)||13.1 ± 5.6||20.7 ± 9.3||p <0.05 |
|Control (n = 26)||12.5 ± 3.0||-||-|
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