Infections of the urinary tract in children

Urinary tract infection in children - a microbial-inflammatory disease of the urinary system without indicating specific location. The term "infection of the urinary system" is used until the localization of the inflammatory process and the etiology of inflammation are clarified. The term is competent at the first stage of the disease, when there is no data for kidney damage in the examination of the patient, but there are signs of microbial involvement of the urinary tract. The diagnosis of "urinary tract infection" is especially valid in infants and young children due to the anatomical and physiological characteristics of the ureter (long and with a wide lumen, prone to bends) and with features of the immunological reactivity of the organism, the consequence of which is the ease of spreading the infection.

ICD-10 codes

• N10. Acute tubulointerstitial nephritis.
• N11. Chronic tubulointerstitial nephritis.
• N11.0. Non-structured chronic pyelonephritis associated with reflux.
• N11.1. Chronic obstructive pyelonephritis.
• N13.7. Uropathy due to vesicoureteral reflux.
• N30. Cystitis.
• N30.0. Acute cystitis.
• N30.1. Interstitial cystitis (chronic).
• N30.9. Cystitis, unspecified.
• N31.1. Reflex bladder, not elsewhere classified.
• N34. Urethritis and urethral syndrome.
• N39.0. Urinary tract infection without established localization.

Epidemiology of urinary tract infections

The prevalence of urinary tract infections varies from 5.6 to 27.5%. On average, it is 18 cases per 1000 children's population.

An analysis of the world statistics shows that in the developed countries of Western Europe the problem of urinary tract infections becomes urgent already from the first days of the child's life.

The prevalence of infections of the urinary system in Western Europe

A country	Year	Authors	Prevalence of IMS,%	Object of study
England	2000	Christian MT et al.	8.40	Girls up to 7 years old
			1.70	Boys under 7 years old
Sweden	2000	Jakobsson V. Et.	1.70	Girls
			1.50	Boys (multicentre study, data from 26 Swedish pediatric centers)
England	1999	Poole C.	5.00	Girls
			1.00	Boys
Sweden	1999	Hansson S, et al.	1.60	Multicentre study of the child population
Finland	1994	Nuutinen M. Et al.	1.62	Girls up to 15 years old
			0.88	Boys under 15 years old

Among full-term newborns, the incidence of urinary tract infections reaches 1%, preterm infants - 4-25%. Newborns with extremely low body weight (<1000 g) have a risk of developing urinary tract infections during the first year of life. Manifestation of urinary tract infection in children of the first year of life is usually associated with the development of the microbial inflammatory process in the kidney parenchyma (pyelonephritis). If at this age the correct diagnosis is not made and the appropriate treatment is not carried out, then the probability of a recurrent course of pyelonephritis with the subsequent formation of foci of nephrosclerosis (wrinkling of the kidney) is very high.

It has been repeatedly shown that the overwhelming number of patients with urinary tract infections are girls, with the exception of children of the first year of life: among infants, 4 times more often than urinary tract infections are diagnosed in boys. From the 2nd to the 12th month of life, urinary tract infections are equally common in boys and girls, after a year - more often in girls. At 7 years of age, 7-9% of girls and 1.6-2% of boys have at least one episode of urinary tract infection, confirmed bacteriologically.

The most likely diagnosis of infections of the urinary tract in children of the first 2 years of life who have a fever, the cause of which is unclear when collecting anamnesis and examining the child.

Frequency of detection of infections of the urinary system in children with fever

A country	Year	Authors	Prevalence of IMS,%	Object of study
USA	2002	Reddy PP, Redman JF	3-10	Children of the first 2-3 months of life with fever
USA	2000	Baraff LJ.	3-4	Boys younger than 2 years with fever
			8-9	Girls younger than 2 years with fever
USA	2000	Kaplan RL et ai.	7.5	Girls younger than 2 years with fever
Australia	1999	Haddon RA et at.	5	Children from 3 months to 3 years with fever
USA	1999	Shaw KN, Gorelik MH	3-5	Children of the first 4 years of life with a fever
USA	1999	American Academy of Pediatrics	5	Children of the first 2 years of life with fever

[1], [2], [3], [4], [5], [6], [7],

Causes of Urinary Tract Infections

Bacteriological studies have shown that the spectrum of microflora depends on many factors:

• the child's age;
• sex;
• the gestational age at the time of the birth of the child;
• period of the disease (debut or relapse);
• conditions of infection (community-based or hospital).

What causes urinary tract infections?

[8], [9], [10], [11]

Pathogenesis of urinary tract infections

Discuss 3 ways of infection with urinary tract infection: ascending (or urinogenic), hematogenous and lymphogenic.

The urinogenic (or ascending) path of infection is most common in children. The upstream pathway of infection is facilitated by colonization with uropathogenic microorganisms of the vestibule vestibule, periurethral area, preputial sac and distal sections of the urethra. In normal colonization, the uropathogenic flora in girls is prevented by normal vaginal microflora, represented mainly by lactobacilli producing lactic acid (lowering the vaginal pH), and hydrogen peroxide, which creates an unfavorable environment for the growth of uropathogenic microbes.

Pathogenesis of urinary tract infections

Symptoms of urinary tract infections

Clinical signs of cystitis in children:

• Frequent painful urination in small portions (dysuria);
• pain in the bladder, soreness in palpation in the suprapubic region;
• incomplete momentary emptying of the bladder, urinary incontinence;
• low-grade or normal temperature;
• leukocyturia;
• bacteriuria.

Symptoms of urinary tract infections

Classification of urinary tract infections

In accordance with the localization of the inflammatory process, infections of the upper parts of the urinary system (pyelonephritis, pyelitis, ureteritis) and lower (cystitis, urethritis) are isolated:

• pyelonephritis - a microbial-inflammatory disease of the kidney parenchyma;
• pyelitis - a microbial-inflammatory disease of the collecting system of the kidney (pelvis and calyces), which is rarely seen in isolation;
• ureteritis is a microbial-inflammatory disease of the ureters;
• cystitis - a microbial-inflammatory disease of the bladder;
• urethritis is a microbial-inflammatory disease of the urethra.

The most common variants of urinary tract infections in children are pyelonephritis and cystitis.

[12], [13], [14], [15]

Diagnosis of urinary tract infections

When examining children with a suspected urinary tract infection, minimally invasive methods with high sensitivity are preferred. The complexity of diagnosing a urinary tract infection is noted first of all in infants (newborns and the first 2 years of life).

Diagnosis of urinary tract infections

[16], [17], [18], [19], [20], [21], [22], [23]

Treatment of urinary tract infections

Later, the onset of adequate antimicrobial therapy in children with a urinary tract infection leads to serious consequences: damage to the kidney parenchyma (with possible formation of wrinkles) and sepsis. An analysis of the results of scintigraphy carried out within 120 hours from the start of treatment showed that antimicrobial therapy prescribed for children with fever and suspected urinary tract infection in the first 24 hours of the disease completely eliminates focal defects in the kidney parenchyma. The beginning of treatment at a later date (2-5 days) leads to the appearance of parenchyma defects in 30-40% of children.

How are urinary tract infections treated?