European Journal of Biomedical and Pharmaceutical Sciences

FOLLOW-UP OF KIDNEY SCARRING AFTER URINARY TRACT INFECTIONS USING TECHNETIUM-99M DIMERCAPTOSUCCINIC ACID SCAN IN PAEDIATRIC JORDANIAN SUBJECTS WITH ACUTE PYELONEPHRITIS

Louai Alqatawna*, Dogan Atiyat, Hana Alsoudi, Baraa Khlaifat, Nizar Ghnmein, Amany Al-ja'afeh, Khaled Al-Khawaldeh and Ahmad Shaban

ABSTRACT

Background: A urinary tract infection is the main frequent bacterial infection in young paediatric subjects. If a urinary tract infection is not managed, acute pyelonephritis might lead to kidney insult, kidney scarring and chronic renal failure. Early confirmation and management of a urinary tract infection is crucial to avoid kidney scarring. The most frequent risk factor of kidney scarring in paediatric subjects following urinary tract infection is vesicoureteral reflux. Technetium-99m dimercaptosuccinic acid (Tc 99m DMSA) scan is the cornerstone to confirm kidney scarring after a urinary tract infection. Objective: The objective was to evaluate the frequency and risk factors of kidney scarring after urinary tract infection in paediatric Jordanian subjects and following management of acute pyelonephritis by Tc 99m DMSA scan. Methods: Our prospective, double-blind investigation included 110 paediatric subjects (< 10 years old, both sexes) with confirmed urinary tract infection and acute pyelonephritis of which kidney cortical lesions were ascertained by primary Tc 99m DMSA scans, at King Hussein Hospital, King Hussein Medical City, Amman, Jordan, during the period of 2010–2020. Subjects were classified into two groups based on kidney scars and risk factors of kidney scars, such as sex, age at confirmation, hydronephrosis, vesicoureteral reflux score and voiding cystourethrogram. The kidney-scarred group (GI, n = 43) and the non-kidney scarred group (GII, n = 67) were formed based on Tc 99m DMSA scans. For age at confirmation, subjects were placed into two groups: < 1 year and > 1 year. The Tc 99m DMSA scan was performed to evaluate the presence of kidney scars. The Tc 99m DMSA scan was pathological if there was one or more sites of reduced cortical uptake with or without cortical outline. Voiding cystourethrogram and Tc 99m DMSA scans were done within a 2–4-month follow-up. Vesicoureteral reflux was scored following voiding cystourethrogram (I–V). Kidney scars were scored as type I, no more than two scars; type II, more than two scars with some normal parenchyma between them; type III, generalised damage to the whole kidney; and type IV, end stage. The chi-square test was used to determine the significance of correlation between categorised parameters. Logistic regression was done to assess the risk factors for kidney scarring. Results: Overall, 43 of 110 subjects (39.1%) had kidney scars based on Tc 99m DMSA scan. There were no remarkable discrepancies in terms of sex and hydronephrosis between the kidney-scarred and non-scarred groups. Age at confirmation > 1 year had a 4.7 times greater frequency of kidney scarring. Vesicoureteral reflux influenced kidney scar production. A vesicoureteral reflux score of III or IV had a 13.6 times greater effect on kidney scar production than a vesicoureteral reflux score of I or II. Paediatric subjects with previous recurrent urinary tract infection experienced kidney scarring. First and recurrent episodes of urinary tract infections were remarkable when compared with increasing vesicoureteral reflux (P < 0.005) and kidney scar (P < 0.05). There was a genitourinary abnormal ultrasound in 31 of 110 (28.2%) subjects, of whom 9 (29.0%) experienced kidney scarring following the first episode of a urinary tract infection. Kidney scars were found in 43 of 110 (39.1%) subjects, of whom 9 (20.9%) were experiencing the first episode of a urinary tract infection. The Tc 99m DMSA scan was pathological in 11 of 43 subjects (25.6%) with normal ultrasound, of whom 8 subjects were experiencing a recurrent urinary tract infection and 3 subjects had pyelonephritis. Conclusion: Vesicoureteral reflux scores and age at confirmation are risk factors of kidney scarring when using Tc 99m DMSA scan following acute pyelonephritis. Increased hydroureteronephrosis and younger age were more correlated with recurrent episodes of urinary tract infection and kidney scarring. Non-invasive Tc 99m DMSA scan is preferred over invasive procedures for follow-up of paediatric subjects with recurrent urinary tract infection.

Keywords: Acute pyelonephritis; Kidney scar; Vesicoureteral reflux; technetium-99m dimercaptosuccinic acid; paediatric subjects; urinary tract infection.