Features of thermography in schoolchildren with arterial hypertension

Abstract

Arterial hypertension occurs as a result of violations of the mechanisms of neurohumoral regulation of the cardiovascular system. Children of pubertal age are most prone to the development of arterial hypertension; it is determined by the vegetative dysfunctions and microcirculatory disorders inherent in these childhood periods. It is proved that microcirculatory disorders are also the basis of disorders of the cardiovascular system, in particular in the regulation of blood pressure. The state of microcirculation can be assessed using infrared thermography.The purpose of the work: to study the features and diagnostic value of thermography of the distal upper limbs in schoolchildren with arterial hypertension.Material and methods. A total of 61 school‑age children were examined. Children were divided into three groups: the first main group (21 people) included children with hypertension, the second main group (20 people) included children with hypertension, the control group (20 people) consisted of children with normal blood pressure. Anamnestic survey and general clinical examination were performed in children. Blood pressure measurement was performed by certified automatic blood pressure monitors (OMRON 705IT, OMRON, Japan) in the morning, in both arms, three times with an interval of 2 minutes. Average pressure values were estimated from percentile tables for age, gender, and height. Infrared thermography in children was performed remotely using a certified Flir One Pro thermal imager with thermal matrix resolution 160x120 pixels. Children were thermographed on their hands, on the back surface, with special attention paid to the distal part of the fingers (projections of the nail plates). The permissible error when measuring the temperature was ± 0.15º C.Results. The following data were obtained by tonometry: in 20 children (32.8%), the level of blood pressure was within the range of 90‑95%, which is estimated as arterial hypertension (2nd main group) in 21 children (34.4%) ‑ exceeded 95%, which is regarded as arterial hypertension (1st main group) in 20 children (32.8%) ‑ was within 25‑75 percentile corridor, corresponds to the normal level (control group). According to thermography, the average highest temperature of the back surface of the distal phalanges in these children was 29.7 ± 0.8 ° C, and ranged from 25.7 ° C to 32.1 ° C. In children from the control group, the average highest temperature was 30, 7 ± 0, 7º s and ranged from 28.9º s to 32.1º C. The highest temperature was recorded on the phalanx of the 3rd finger in 17 (85.0%) children, on the phalanx of the 2nd finger ‑ in 2 children (10 0%) and one child (5.0%) ‑ on the phalanx of the 4th finger, the lowest ‑ on the phalanx of the 5th finger. In children with hypertension, a decrease in the maximum fusion temperature on the dorsal surface of the hand was observed, and a shift in the area of the highest fusion on the index finger compared to children in the control group, who had this area mostly on the middle finger. Children with hypertension also exhibited a change in the thermographic pattern of the hand with a decrease in heat radiation in the 4th and 5th fingers, unlike children in the control group.Conclusions. 1. Children with arterial hypertension have features of a thermal picture, which are manifested by a decrease in the maximum temperature of thermionic emission, which, obviously, is associated with an increase in peripheral resistance of blood flow and a slowdown of blood flow in capillaries. The expansion of the maximum zone and the dominance of thermal radiation on the index finger, unlike children with normal levels of blood pressure, can be regarded as a diagnostic sign of arterial hypertension. 2. Children with hypertension according to the results of thermography should be assigned to the risk group for the development of arterial hypertension. 3. Risk factors that worsen heat radiation include microcirculation disorders (a decrease in the linear density of capillaries), as well as overweight and lack of exercise in schoolchildren. 4. Infrared thermography can be recommended as one of the methods for the early diagnosis of arterial hypertension in children.