Annals of Tropical Paediatrics International Child Health
ISSN: 0272-4936 (Print) 1465-3281 (Online) Journal homepage: http://www.tandfonline.com/loi/ypch19
Evaluation of urinary tract infection in malnourished black children Udai K. Kala & David W. C. Jacobs To cite this article: Udai K. Kala & David W. C. Jacobs (1992) Evaluation of urinary tract infection in malnourished black children, Annals of Tropical Paediatrics, 12:1, 75-81, DOI: 10.1080/02724936.1992.11747549 To link to this article: http://dx.doi.org/10.1080/02724936.1992.11747549
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Date: 17 August 2017, At: 22:14
Annals of Tropz"cal Paediatrics (1992) 12,75-81
Evaluation ofurinary tract infection in malnourished black children UDAI K. KALA & DAVID W.C. JACOBS
Downloaded by [Australian Catholic University] at 22:14 17 August 2017
Department of Paediatrics, University of the Witwatersrand and Baragwanath Hospital, Johannesburg, South Africa (Received3June 1991)
Summary Urinary tract infection (UTI) is a weil recognized complication in malnourished children. The need to investigate these patients for underlying renal pathology has not been clearly defined. Seventy-five children with malnutrition were evaluated for UTI by culture of urine obtained suprapubically prior to antibiotic therapy. Ali patients with UTI were investigated with renal ultrasonography, intravenous pyelography (IVP) and voiding cystourethrography (VCU). Haemoglobin, white cell count, serum urea, creatinine and electrolytes were determined in ali the children. The mean age of the children was 15.5 months (range 3-60 months). UTI was diagnosed in 26 (34.7~ 0 ), of whom 21 (81 °0 ) were boys. The overall prevalence ofUTI in those with kwashiorkor/marasmic kwashiorkor was 42° 0 • Escherichia coli was the organism most commonly cultured (84.6° 0 ). Renal sonography, IVP and VCU were normal in ali infected cases and vesicoureteric reflux was not detected in any. This study confirms the high prevalence of UTI in malnourished children. As no anatomical abnormalities were demonstrated in the patients with UTI, imaging of the renal tract other than real sonography does not appear to be indicated in the malnourished child in a first episode of UTI with normal renal function.
Introduction Urinary tract infection (UTI) is a weil recognized complication in malnourished children. 1-9 The need to search for underlying renal abnormalities in these patients, however, has never been established. Postmortem studies previously have demonstrated pyelonephritis and renal abscesses in children dying of malnutrition. 1'2The routine use of newer broad-spectrum antibiotics has improved the mortality from infection. 10 •11 Isolated reports in which intravenous pyelography (IVP) and vesicourethrography (VCU) were performed have documented Reprint requests to: Dr U. K. Ka1a, Depanment of Paediatrics, Baragwanath Hospital, P.O. Bensham, 2013, Republic of South Africa.
vesicoureteric reflux and obstruction in sorne ofthese selected, infected malnourished children.4•5•9 With the limited financial and technical resources available in those areas in which malnutrition is most prevalent, i.e. developing countries, extensive and expensive radiological investigations may be inappropriate in the average case. The purpose of this study was to determine prospectively the need for radiological investigation in the black malnourished child with UTI because of the low prevalence of primary vesicoureteric reflux (VUR) reported in South African 12 and American black children. 13 •14 In our local experience, only four patients with primary VUR out of a total of 392 patients admitted with proven UTI have been documented in the past 8 years (unpublished data).
76
U. K. Kala & D. W. C.Jacobs TABLE 1. Sex and age distribution of malnourished infants with and without UTI
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Total of patients Male Female Male/female ratio Age (months) (Mean [SD]) Males Females
U rinary tract infection
Nourinary tract infection
pvalue
26 21 5 4.2:1
49 23 26 0.88:1
0.005*
17.2 (17.3) 14.1 (10.3) 19.1 (7.7)
15.5 (9.8) 18.3 (9.6) 13.5 (10.6)
ns 0.02 0.14
Statistics calculated using unpaired Student's t-test. *Statistics calculated using X2 test. ns: Not significant.
Patients and methods The study group comprised 75 malnourished children who were admitted consecutively to an acute paediatric ward. Their nutritional status was assessed according to the Weilcome Trust International Working Party classification 15 using the National Center for Health Statistics (NCHS) charts. 16 In the clinical examination, special note was made if boys had been circumcized. Urine specimens were obtained on admission by suprapubic aspiration 17 from ali the children prior to any antibiotic therapy. UTI was definedas any growth oforganisms in the urine plated immediately on a dipslide (Uricult (R)-Boehringer Mannheim) and incubated at 37°C. The dipslide was read at 24 and 48 hours for evidence ofbacterial growth. Ali positive dipslide cultures were read for colony count by reference to the manufacturer's chart 18 and bacterial identification was confirmed by standard microbiological methods. A full blood count, serum urea, electrolytes and creatinine, and blood cultures were done on ali the children. Those with UTI were treated with appropriate antibiotics and the dipslide test was repeated 3 days after commencement of antibiotic therapy.
Abdominal sonography was done on ali infected patients to evaluate renal size, morphology and position of the kidneys. 19 The presence of renal scarring and VUR were evaluated by IVP and VCU, respectively, 4-6 weeks after the UTI had been treated. Informed consent was obtained from ali the parents of the children and the study was approved by the Committee for Research on Human Subjects of the University of the Witwatersrand.
Statistical methods The anthropometrie and biochemical parameters in those with and those without UTI were compared using the unpaired Student's t-test. The male:female ratio was compared using the x2 test (see Table I).
Results The mean age of the 75 children was 15.4 months with a range of 3-60 months. UTI was found in 26 (35%), ali of whom had a growth of greater than or equal to 100 000 bacteria per ml of urine. The nutritional status and the number of those with and without UTI in both boys and girlsareshowninFig.l. Therewasnostatistical difference in the prevalence of UTI
UT! in malnourished black children
77
20 18 16 14
ë"'
12
0Q.
10
.~
0 ci
z
8
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6 4
M
2 0
Underweight
Morosmic kwashiorkor
FIG. l. Distribution of the nutritional status, sex and presence or absence ofUTI (M, Male; F, Female; D, UTI; IZI NoUTI).
between those with oedema, i.e. kwashiorkor and marasmic kwashiorkor, and the nonoedematous. In the overali group, there was no age difference between the children with UTI and those without, but there was a significant male predominance in those who were infected (4.1:1; p=0.005), and the mean age of the infected boys was significantly less than that of the non-infected boys (p=0.02). The difference in the mean weights between the infected and non-infected children was statisticaliy significant (p = 0.04), those who were infected being lighter and having a lower mean percentage expected weight-for-age ( p = 0.005). A similar difference in urea ( p = 0.005) and creatinine (p = 0.02) was noted between the infectedandnoninfected, and probably reflects the difference in dietary intake of protein and muscle bulk, respectively (Table Il). Patients with UTI had higher white celi counts (p=0.01) despite being more malnourished. There was no statisticaliy significant difference in the haemoglobin, serum sodium, potassium or chloride concentration between the groups with or without UTI (Table Il).
The infecting organisms in the urine revealed a pattern similiar to that which would be expected to occur in weli nourished children/0'21 with E. coli in 22 (84.6%), Proteus mirabilis in two, Klebsiella pneumoniae in one and Pseudomonas aeruginosa in one case. Blood cultures on admission were negative in ali the children. There were three deaths, ali occurring in the uninfected group. This gave an overali mortality of 4%. No post-mortem studies were performed. Abdominal sonography in the children with infection showed normal appearances and the IVP and VCU did not detect any scarring or VUR, respectively. Discussion
There have been many studies ofUTI in malnourished patients 1-9 ' 22 in which the prevalencehasvariedfrom600 to31 ~'o· Thewide range noted in these studies may reflect varying degrees of protein-energy malnutrition or differences in study design. The infants in this study had a high prevalence of UTI possibly caused by an acute metabolic derangement, especially of protein, electrolyte, trace elements, multiple vitamin deficiencies and
78
U. K. Kala & D. W. C.Jacobs TABLE II. Comparison of anthropometrie, haematological and biochemical parameters ofmalnourished infants with and without UTI
Downloaded by [Australian Catholic University] at 22:14 17 August 2017
U rinary tract infection Mean(SD) Weight(kg) Percentage expected weight-for-age Height(cm) Haemoglobin (g/dl) White cell count (109 /l) Sodium (mmol/1) Potassium (mmol/1) Chloride (mmol/1) Urea (mmol/1) Creatinine (.umol/1)
No urinary tract infection Mean(SD)
5.4 (2.3)
6.4 (2.3)
49.3 (7.3) 65.4 (8.0) 9.2 (1.5) 14.3 (9.8) (3) 137 3.4 (1.2) (5) 99 2.9 (1.3) 45 (19)
62.4 (18.5) 66.0 (16.5 9.4 (2.5) 12.1 (4.8) 125 (29) 3.6 (1.2) 98 (23) 5.5 (4.8) 61 (33)
pvalue 0.04 0.005 ns ns 0.01 ns ns ns 0.005 0.02
Statistics calculated using unpaired Student's t-test. ns: Not significant.
immune status, al one or in combination. W e did not demonstrate any plasma electrolyte disturbance and were unable to study the other factors. No specifie factors relating to the increased susceptibility to UTI in malnutrition have been defined. The increased susceptibility of these children to infection in general may be due to the breakdown of anatomical barriers, depressed cell-mediated immunity, depression of opsonic activity, decreased phagocytosis or decreased components of complement with the exception of the fourth component. I t has been noted that the uncircumcized boy is more susceptible to UTI, owing to colonization of the periurethral and preputial areas by organisms such as B. Coli23 •24 and this may have been a contributing factor in our children. None of the 44 boys had been circumcized and 21 (48%) were infected. However, circumcision is exceptional at this age in this population and no firm conclusion can be drawn from these findings. The other factors which may be involved in the pathogenesis of UTI in the malnourished infant which need further study may include those listed in Table III.
TABLE III. Possible factors in the pathogenesis ofUTI in severe malnutrition 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Protein deficiency. Vitamin A deficiency. Decreased mucin production in the bladder. Deficiency of secretory immunoglobulin A in the urine. Lymphatic spread. Electrolyte disturbances, especially hypokalaemia. Virulence of the organism. Periurethral bacterial flora. Breakdown of anatomical barriers. Combination of above factors.
Vitamin A is known to be important in maintaining the integrity of ali epithelial surfaces, including the transitional epithelium of the bladder, ureter and renal pelvis. 25- 27 Deficiency of vitamin A may predispose to UTI by a number of mechanisms. Firstly, the heaping of epithelium that may occur especially in the urethra and the bladder neck owing to squamous stratification of mucosa might result in functional obstruction and stasis, predisposing to infection. This may be more important in a boy with a longerurethra. Secondly, there may be decreased mucin
UTI in malnourished black children
79
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1+----·various pothogenetic mechonisms
No obnormolities detected
Observe and follow up
FIG. 2. Evaluation of urinary tract infection in malnourished children.
production as a consequence of loss of the secretory epithelial surface, which may further enhance adherence of organisms to the mucosa and thus predispose to infection. No evidence was found in our study to support this. The concentration of immunoglobulin A (lgA) in the serum is often elevated in malnourished patients but there is a mild but significant decrease in secretory !gA, 28•29 which might play a role in UTI by permitting bacterial adherence to periurethral and uroepithelium. 30 Secretory !gA has been evaluated in malnourished children with UTI by Buchanan et al. 3 and no difference in secretory lgA in the urine was found compared with that in weil nourished controls. As the number of patients included in that
study was small, the conclusion might not be valid. Many malnourished patients have gastroenteritis, the aetiology of which is multifactorial.10'21'31 Gastro-enteritis, itself, is probably not the cause of the UTI but may contribute to the colonization of the periurethral and uroepithelium owing to poor perineal toilet and possible lymphatic spread of the organism. Hypokalaemia has been described as producing temporary atonie ureters and pelves resulting in functional obstruction causing UTI. 32 Malnourished children have marked depletion of total body and serum potassium which may possibly contribute to the pathogenesis of UTI in these patients by causing atony, functional obstruction and infection.
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80
U. K. Ka/a & D. W. C.Jacobs
Our observation of normal ultrasonography and serum potassium levels does not support this. The combination of protein and vitamin A deficiency, electrolyte and immunological disturbances, poor perineal toilet with high prevalence of diarrhoea, the virulence of the organism, the infecting dose, the presence of p-fimbrae, 33' 34 and genetic and sexual predilections may account for different pathogenetic mechanisms for UTI in malnourished black children, as outlined in Table III.
Conclusion Previous studies in severe malnutrition have shown that bacteraemia, pneumonia and gastro-enteritis are common infections but also that UTI is as common, which we have confirmed in our study. Therefore it should be actively sought by suprapubic aspiration and if present should be treated appropria tel y. The pathogens are likely to be similiar to those found in weil nourished children but the pathogenetic mechanisms are probably different. Owing to the very low prevalence of VUR in black children, we wish to recommend that malnourished children with UTI should have only an abdominal sonar done as part of their routine investigation and that IVP and VCU should be reserved for patients with abnormalities detected on abdominal sonography or those having recurrent UTI or persistently abnormal biochemistry, as outlined in Fig. 2.
Acknowledgements W e wish to thank Professors P. D. Thomson and J. M. Pettifor for reviewing the paper and the latter for his invaluable assistance with the statistical analysis; Boehringer Mannheim for supply of Uricult Dipslides; Mr B. R. K. Kala for technical assistance in doing the figure and tables; the paediatric staff at Baragwanath Hospital for their encouragement; and Mrs V. N. Sehlako for typing this manuscript.
References
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7
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9
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13 14 15
16
17
18
19
Campbell JAH. The morbid anatomy of infantile malnutrition in Cape Town. Arch Dis Child 1956; 31:310-14. Stirling GA. Renal pathology in malnourished infants. Arch Dis Child 1962; 37:378-80. Buchanan N, Fairburn JA, Schmaman A, Vis GH. Urinary tract infection and secretory urinary IgA in malnutrition. S Mr Med J 1973; 47:1179-81. Brooke OG, Kerr DS. The importance of routine urine culture in malnourished children. J Trop Pediatr 1973; 19:348-9. Bodaghi E, Sadre M, Ziai M. Bacteriuria in malnourished Iranian children. J Trop Pediatr 1979; 24: 77-9. Schrimshaw NS. Interaction of malnutrition and infection; advances in understanding. In: Olsen RE, ed. Protein-Calorie Malnutrition. The Nutrition Foundation. A monograph series. New York: Academie Press, 1975; 353-67. Berkowitz FE. Infections in children with severe protein-energy malnutrition. Ann Trop Pediatr 1983; 2:79-83. Phillips I, Wharton B. Acute bacterial infection in kwashiorkor and marasmus. Br Med J 1968; 1: 407-9. Morton RE, Lawande R. Frequency and clinical features of urinary tract infection in paediatric outpatients in Nigeria. J Trop Paediatr 1982; 2:113-17. Smythe PM. Changes in intestinal bacterial flora and role of infection in kwashiorkor. Lan cet 1959; 2:724. Morehead CD, Morehead M, Allen DM, Olsen RE. Bacterial infections in malnourished children. J Trop Pediatr 1974; 20:141-7. Cremin BJ. Observations on vesico-ureteric reflux and intrarenal reflux: a review and survey of material. Clin Radiol1979; 30:607-21. King LR, Surian MA, Wendel RM, Burden JJ. Vesicoureteral reflux. JAMA 1968; 203:103-8. Askari A, Belman B. Vesicoureteral reflux in black girls. J Urol1982; 127:747-8. Wellcome Trust International Working Party. Classification of infantile malnutrition. Lancet 1970; 2:302-3. National Center for Health Statistics. NCHS Growth charts, 1976. Monthly Vital Statistics Report, vol. 25, no. 3, Suppl (HRA) 7fr-1120. Rockville, MA: Health Resources Administration, 1976. Pryles CV. Percutaneous bladder aspiration and other methods of urine collection for bacteriologie study. Pediatries 1965; 36:128-31. Buchanan N. A dip-slide test for bacteriuria in protein-calorie malnutrition. S Mr Med J 1971; 45: 320-1. Johnson CE, De Baz B, Shurin PA, DeBartolomo R. Renal ultrasound and evalution of urinary tract infection in children. Pediatries 1986; 78:871-9.
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UT/ in malnourished black children 20 Kunin CM. Epidemiology and natural history of urinry tract infection in school age children. Pediatr Clin North Am 1971; 18:509-28. 21 Ginsberg CM, McCracken GH. Urinary tract infections in young infants. Pediatries 1982; 69:409-12. 22 FreyreEA,RondonO,BedoyaJ,etal. The incidence of bacteriuria and pyuria in Peruvian children with malnutrition. J Pediatr 1973; 83:57--61. 23 Wisell TE, Smith FR, Bass JW. Decreased incidence of urinary tract infections in circurncised male infants. Pediatries 1985; 75:901-3. 24 Bollgren I, Winberg J. The periurethral aerobic bacterial flora in healthy boys and girls. Acta Paediatr Scand 1976; 65:74-80. 25 McLaren DS. The fat-soluble vitamins and Protein Calorie (Energy) Malnutrition FoWldation. A monograph series. New York: Academie Press, 1975; 181-200. 26 Behrman RE, Vaughan VC, Nelson WE, eds. Nelson Textbook of Pediatries, 13th edn. New York: WB Saunders, 1987; 142-4. 27 Neumann CG. Non specifie host factors and infection in malnutrition. In: Suskind RM, ed. Mal-
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nutrition and The Immune Response. New York: Raven Press, 1977; 355-71. Sirisinha S, Suskind RM, Edelman R, Asvapaka C, Olsen RE. Secretory and serum IgA in children with protein-calorie malnutrition. Pediatries 1975; 55: 166-70. Raghuramulu N, Bhaskaram C. Secretory IgA in protein-calorie malnutrition. Arch Dis Child 1976; 51:871-4. Matthias F, Mehls 0, Rauterberg E, Ritz E. Urinary IgA in children with urinary tract infection. J Pediatr 1986; 109:416-21. Fitzgerald JF, Clark JH. Chronic diarrhea. Pediatr Clin North Am 1982; 29:221-31. Ghose RR, }ivan HR. Transient urinary tract dilatation associated with hypokalaemia. Br Med J 1985; 209:1319-20. Winberg J. P-fimbriae, bacterial adhesion and pyelonephritis. Arch Dis Child 1984; 59:180-4. Marild S, Wenergren B, Hellstrôm M, et al. Bacterial virulence and infiammatory response in infants with febrile urinary tract infection or screening bacteriuria. J Pediatr 1988; 112:348-54
ISSN: 0272-4936 (Print) 1465-3281 (Online) Journal homepage: http://www.tandfonline.com/loi/ypch19
Evaluation of urinary tract infection in malnourished black children Udai K. Kala & David W. C. Jacobs To cite this article: Udai K. Kala & David W. C. Jacobs (1992) Evaluation of urinary tract infection in malnourished black children, Annals of Tropical Paediatrics, 12:1, 75-81, DOI: 10.1080/02724936.1992.11747549 To link to this article: http://dx.doi.org/10.1080/02724936.1992.11747549
Published online: 13 Jul 2016.
Submit your article to this journal
View related articles
Citing articles: 11 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ypch19 Download by: [Australian Catholic University]
Date: 17 August 2017, At: 22:14
Annals of Tropz"cal Paediatrics (1992) 12,75-81
Evaluation ofurinary tract infection in malnourished black children UDAI K. KALA & DAVID W.C. JACOBS
Downloaded by [Australian Catholic University] at 22:14 17 August 2017
Department of Paediatrics, University of the Witwatersrand and Baragwanath Hospital, Johannesburg, South Africa (Received3June 1991)
Summary Urinary tract infection (UTI) is a weil recognized complication in malnourished children. The need to investigate these patients for underlying renal pathology has not been clearly defined. Seventy-five children with malnutrition were evaluated for UTI by culture of urine obtained suprapubically prior to antibiotic therapy. Ali patients with UTI were investigated with renal ultrasonography, intravenous pyelography (IVP) and voiding cystourethrography (VCU). Haemoglobin, white cell count, serum urea, creatinine and electrolytes were determined in ali the children. The mean age of the children was 15.5 months (range 3-60 months). UTI was diagnosed in 26 (34.7~ 0 ), of whom 21 (81 °0 ) were boys. The overall prevalence ofUTI in those with kwashiorkor/marasmic kwashiorkor was 42° 0 • Escherichia coli was the organism most commonly cultured (84.6° 0 ). Renal sonography, IVP and VCU were normal in ali infected cases and vesicoureteric reflux was not detected in any. This study confirms the high prevalence of UTI in malnourished children. As no anatomical abnormalities were demonstrated in the patients with UTI, imaging of the renal tract other than real sonography does not appear to be indicated in the malnourished child in a first episode of UTI with normal renal function.
Introduction Urinary tract infection (UTI) is a weil recognized complication in malnourished children. 1-9 The need to search for underlying renal abnormalities in these patients, however, has never been established. Postmortem studies previously have demonstrated pyelonephritis and renal abscesses in children dying of malnutrition. 1'2The routine use of newer broad-spectrum antibiotics has improved the mortality from infection. 10 •11 Isolated reports in which intravenous pyelography (IVP) and vesicourethrography (VCU) were performed have documented Reprint requests to: Dr U. K. Ka1a, Depanment of Paediatrics, Baragwanath Hospital, P.O. Bensham, 2013, Republic of South Africa.
vesicoureteric reflux and obstruction in sorne ofthese selected, infected malnourished children.4•5•9 With the limited financial and technical resources available in those areas in which malnutrition is most prevalent, i.e. developing countries, extensive and expensive radiological investigations may be inappropriate in the average case. The purpose of this study was to determine prospectively the need for radiological investigation in the black malnourished child with UTI because of the low prevalence of primary vesicoureteric reflux (VUR) reported in South African 12 and American black children. 13 •14 In our local experience, only four patients with primary VUR out of a total of 392 patients admitted with proven UTI have been documented in the past 8 years (unpublished data).
76
U. K. Kala & D. W. C.Jacobs TABLE 1. Sex and age distribution of malnourished infants with and without UTI
Downloaded by [Australian Catholic University] at 22:14 17 August 2017
Total of patients Male Female Male/female ratio Age (months) (Mean [SD]) Males Females
U rinary tract infection
Nourinary tract infection
pvalue
26 21 5 4.2:1
49 23 26 0.88:1
0.005*
17.2 (17.3) 14.1 (10.3) 19.1 (7.7)
15.5 (9.8) 18.3 (9.6) 13.5 (10.6)
ns 0.02 0.14
Statistics calculated using unpaired Student's t-test. *Statistics calculated using X2 test. ns: Not significant.
Patients and methods The study group comprised 75 malnourished children who were admitted consecutively to an acute paediatric ward. Their nutritional status was assessed according to the Weilcome Trust International Working Party classification 15 using the National Center for Health Statistics (NCHS) charts. 16 In the clinical examination, special note was made if boys had been circumcized. Urine specimens were obtained on admission by suprapubic aspiration 17 from ali the children prior to any antibiotic therapy. UTI was definedas any growth oforganisms in the urine plated immediately on a dipslide (Uricult (R)-Boehringer Mannheim) and incubated at 37°C. The dipslide was read at 24 and 48 hours for evidence ofbacterial growth. Ali positive dipslide cultures were read for colony count by reference to the manufacturer's chart 18 and bacterial identification was confirmed by standard microbiological methods. A full blood count, serum urea, electrolytes and creatinine, and blood cultures were done on ali the children. Those with UTI were treated with appropriate antibiotics and the dipslide test was repeated 3 days after commencement of antibiotic therapy.
Abdominal sonography was done on ali infected patients to evaluate renal size, morphology and position of the kidneys. 19 The presence of renal scarring and VUR were evaluated by IVP and VCU, respectively, 4-6 weeks after the UTI had been treated. Informed consent was obtained from ali the parents of the children and the study was approved by the Committee for Research on Human Subjects of the University of the Witwatersrand.
Statistical methods The anthropometrie and biochemical parameters in those with and those without UTI were compared using the unpaired Student's t-test. The male:female ratio was compared using the x2 test (see Table I).
Results The mean age of the 75 children was 15.4 months with a range of 3-60 months. UTI was found in 26 (35%), ali of whom had a growth of greater than or equal to 100 000 bacteria per ml of urine. The nutritional status and the number of those with and without UTI in both boys and girlsareshowninFig.l. Therewasnostatistical difference in the prevalence of UTI
UT! in malnourished black children
77
20 18 16 14
ë"'
12
0Q.
10
.~
0 ci
z
8
Downloaded by [Australian Catholic University] at 22:14 17 August 2017
6 4
M
2 0
Underweight
Morosmic kwashiorkor
FIG. l. Distribution of the nutritional status, sex and presence or absence ofUTI (M, Male; F, Female; D, UTI; IZI NoUTI).
between those with oedema, i.e. kwashiorkor and marasmic kwashiorkor, and the nonoedematous. In the overali group, there was no age difference between the children with UTI and those without, but there was a significant male predominance in those who were infected (4.1:1; p=0.005), and the mean age of the infected boys was significantly less than that of the non-infected boys (p=0.02). The difference in the mean weights between the infected and non-infected children was statisticaliy significant (p = 0.04), those who were infected being lighter and having a lower mean percentage expected weight-for-age ( p = 0.005). A similar difference in urea ( p = 0.005) and creatinine (p = 0.02) was noted between the infectedandnoninfected, and probably reflects the difference in dietary intake of protein and muscle bulk, respectively (Table Il). Patients with UTI had higher white celi counts (p=0.01) despite being more malnourished. There was no statisticaliy significant difference in the haemoglobin, serum sodium, potassium or chloride concentration between the groups with or without UTI (Table Il).
The infecting organisms in the urine revealed a pattern similiar to that which would be expected to occur in weli nourished children/0'21 with E. coli in 22 (84.6%), Proteus mirabilis in two, Klebsiella pneumoniae in one and Pseudomonas aeruginosa in one case. Blood cultures on admission were negative in ali the children. There were three deaths, ali occurring in the uninfected group. This gave an overali mortality of 4%. No post-mortem studies were performed. Abdominal sonography in the children with infection showed normal appearances and the IVP and VCU did not detect any scarring or VUR, respectively. Discussion
There have been many studies ofUTI in malnourished patients 1-9 ' 22 in which the prevalencehasvariedfrom600 to31 ~'o· Thewide range noted in these studies may reflect varying degrees of protein-energy malnutrition or differences in study design. The infants in this study had a high prevalence of UTI possibly caused by an acute metabolic derangement, especially of protein, electrolyte, trace elements, multiple vitamin deficiencies and
78
U. K. Kala & D. W. C.Jacobs TABLE II. Comparison of anthropometrie, haematological and biochemical parameters ofmalnourished infants with and without UTI
Downloaded by [Australian Catholic University] at 22:14 17 August 2017
U rinary tract infection Mean(SD) Weight(kg) Percentage expected weight-for-age Height(cm) Haemoglobin (g/dl) White cell count (109 /l) Sodium (mmol/1) Potassium (mmol/1) Chloride (mmol/1) Urea (mmol/1) Creatinine (.umol/1)
No urinary tract infection Mean(SD)
5.4 (2.3)
6.4 (2.3)
49.3 (7.3) 65.4 (8.0) 9.2 (1.5) 14.3 (9.8) (3) 137 3.4 (1.2) (5) 99 2.9 (1.3) 45 (19)
62.4 (18.5) 66.0 (16.5 9.4 (2.5) 12.1 (4.8) 125 (29) 3.6 (1.2) 98 (23) 5.5 (4.8) 61 (33)
pvalue 0.04 0.005 ns ns 0.01 ns ns ns 0.005 0.02
Statistics calculated using unpaired Student's t-test. ns: Not significant.
immune status, al one or in combination. W e did not demonstrate any plasma electrolyte disturbance and were unable to study the other factors. No specifie factors relating to the increased susceptibility to UTI in malnutrition have been defined. The increased susceptibility of these children to infection in general may be due to the breakdown of anatomical barriers, depressed cell-mediated immunity, depression of opsonic activity, decreased phagocytosis or decreased components of complement with the exception of the fourth component. I t has been noted that the uncircumcized boy is more susceptible to UTI, owing to colonization of the periurethral and preputial areas by organisms such as B. Coli23 •24 and this may have been a contributing factor in our children. None of the 44 boys had been circumcized and 21 (48%) were infected. However, circumcision is exceptional at this age in this population and no firm conclusion can be drawn from these findings. The other factors which may be involved in the pathogenesis of UTI in the malnourished infant which need further study may include those listed in Table III.
TABLE III. Possible factors in the pathogenesis ofUTI in severe malnutrition 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Protein deficiency. Vitamin A deficiency. Decreased mucin production in the bladder. Deficiency of secretory immunoglobulin A in the urine. Lymphatic spread. Electrolyte disturbances, especially hypokalaemia. Virulence of the organism. Periurethral bacterial flora. Breakdown of anatomical barriers. Combination of above factors.
Vitamin A is known to be important in maintaining the integrity of ali epithelial surfaces, including the transitional epithelium of the bladder, ureter and renal pelvis. 25- 27 Deficiency of vitamin A may predispose to UTI by a number of mechanisms. Firstly, the heaping of epithelium that may occur especially in the urethra and the bladder neck owing to squamous stratification of mucosa might result in functional obstruction and stasis, predisposing to infection. This may be more important in a boy with a longerurethra. Secondly, there may be decreased mucin
UTI in malnourished black children
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1+----·various pothogenetic mechonisms
No obnormolities detected
Observe and follow up
FIG. 2. Evaluation of urinary tract infection in malnourished children.
production as a consequence of loss of the secretory epithelial surface, which may further enhance adherence of organisms to the mucosa and thus predispose to infection. No evidence was found in our study to support this. The concentration of immunoglobulin A (lgA) in the serum is often elevated in malnourished patients but there is a mild but significant decrease in secretory !gA, 28•29 which might play a role in UTI by permitting bacterial adherence to periurethral and uroepithelium. 30 Secretory !gA has been evaluated in malnourished children with UTI by Buchanan et al. 3 and no difference in secretory lgA in the urine was found compared with that in weil nourished controls. As the number of patients included in that
study was small, the conclusion might not be valid. Many malnourished patients have gastroenteritis, the aetiology of which is multifactorial.10'21'31 Gastro-enteritis, itself, is probably not the cause of the UTI but may contribute to the colonization of the periurethral and uroepithelium owing to poor perineal toilet and possible lymphatic spread of the organism. Hypokalaemia has been described as producing temporary atonie ureters and pelves resulting in functional obstruction causing UTI. 32 Malnourished children have marked depletion of total body and serum potassium which may possibly contribute to the pathogenesis of UTI in these patients by causing atony, functional obstruction and infection.
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U. K. Ka/a & D. W. C.Jacobs
Our observation of normal ultrasonography and serum potassium levels does not support this. The combination of protein and vitamin A deficiency, electrolyte and immunological disturbances, poor perineal toilet with high prevalence of diarrhoea, the virulence of the organism, the infecting dose, the presence of p-fimbrae, 33' 34 and genetic and sexual predilections may account for different pathogenetic mechanisms for UTI in malnourished black children, as outlined in Table III.
Conclusion Previous studies in severe malnutrition have shown that bacteraemia, pneumonia and gastro-enteritis are common infections but also that UTI is as common, which we have confirmed in our study. Therefore it should be actively sought by suprapubic aspiration and if present should be treated appropria tel y. The pathogens are likely to be similiar to those found in weil nourished children but the pathogenetic mechanisms are probably different. Owing to the very low prevalence of VUR in black children, we wish to recommend that malnourished children with UTI should have only an abdominal sonar done as part of their routine investigation and that IVP and VCU should be reserved for patients with abnormalities detected on abdominal sonography or those having recurrent UTI or persistently abnormal biochemistry, as outlined in Fig. 2.
Acknowledgements W e wish to thank Professors P. D. Thomson and J. M. Pettifor for reviewing the paper and the latter for his invaluable assistance with the statistical analysis; Boehringer Mannheim for supply of Uricult Dipslides; Mr B. R. K. Kala for technical assistance in doing the figure and tables; the paediatric staff at Baragwanath Hospital for their encouragement; and Mrs V. N. Sehlako for typing this manuscript.
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