Xanthogranulomatous pyelonephritis is associated with higher tissue expression of monocyte chemotactic protein-1

Biomarkers in urinary tract infections - which ones are suitable for diagnostics and follow-up?

Introduction: Urinary tract infections (UTIs) are one of the most common infections worldwide. Under special circumstances, clinicians must rely on laboratory findings, which might have a weak predicting value, misguiding the practitioners and leading to incorrect diagnosis and overuse of antibiotics. Therefore, there is an urgent need for reliable biomarkers in UTIs. Methods: We performed a literature search for biomarkers used in UTIs from January 1999 until May 2020. We used "urinary tract infection" and "biomarker" as the main key words in the PubMed, Medline and Cochrane databases. After peer review, we excluded the duplicates and identified the suitable articles, from which we collected the data and divided the available biomarkers into 5 groups: i) conventional markers; ii) promising, thoroughly studied biomarkers; iii) promising biomarkers that need further studies; iv) biomarkers of unknown significance; v) controversial, not useful markers. Results: We found 131 articles, mostly from the paediatric population. Neutrophil gelatinase-associated lipocalin (NGAL) and interleukins (IL) have a leading role in diagnosing and differentiating UTIs based on a lot of observational, comparative trials. Heparin Binding Protein (HBP), Lactoferrin (LF), Heat-Shock Protein-70 (HSP-70), Human Defensin-5 (HD-5), Lipopolysaccharide Binding Protein (LBP) and mass spectrometry studies are promising, but confirming data are lacking. The measurable components of the innate immune system and local host cell response could be appropriate biomarkers, but their significance is currently unknown. Conclusions: Conventional biomarkers for UTIs have low specificity. The use of urinary NGAL and interleukins could improve the sensitivity and specificity of laboratory diagnosis of UTIs.

Thyroglossal Duct Cyst Associated with Xanthogranulomatous Inflammation

Xanthogranulomatous inflammation (XGI) is an uncommon destructive chronic inflammatory process mainly occurring in the kidney and gallbladder, characterized by the accumulation of foamy histiocytes, multinucleated giant cells (Touton type), cholesterol clefts and chronic inflammatory cells. The head and neck region is an uncommon site for XGI. This type of inflammatory reaction has been defined in branchial cleft cyst, salivary gland tumors following fine-needle aspiration biopsies, Rathke's cleft cyst in the pituitary gland, and colloid cyst in the 3rd ventricle. We present herein a unique case of ruptured thyroglossal duct cyst leading to XGI, characterized by an infiltrative subcutaneous central neck lesion, clinically mimicking a thyroid carcinoma. In addition, we also summarize current insights into the pathogenesis of XGI in the head and neck region.

[Diffuse xanthogranulomatous pyelonephritis in infant]

We report a case of a renal mass in a 4-month boy, which occured during the assessment of a pelvi-calyceal dilatation diagnosed at 23 weeks of gestational age. There was no history of urinary infection, fever or weight loss. Physical examination revealed a mass of the left flank with significant flank tenderness. Laboratory test showed a biological inflammatory syndrome and urine culture was negative. Investigations including ultrasound and computed tomography scan were suggestive of diffuse xanthogranulomatous pyelonephritis with a non-functioning left kidney. Left total nephrectomy was performed through a lumbar incision with an extraperitoneal approach. The kidney was enlarged with a dilated pelvis containing pus upstream of a proximal ureteral atretic segment. Pathological examination of the kidney confirmed the diagnosis of diffuse xanthogranulomatous pyelonephritis. The boy remains well at 1 year follow-up. Xanthogranulomatous pyelonephritis is very rare in infants. It is an uncommon severe progressive renal infection resulting in destruction of renal parenchyma, histologically replaced by xanthomatous cells and granulomatous reaction. Pathogenesis of xanthogranulomatous pyelonephritis remains unclear. But it is well known that urinary tract obstruction and renal lithiasis are determining factors. It can occur in variant clinical forms but its symptoms remain non-specific. Curative treatment consists in nephrectomy and definitive diagnosis is made on histological examination of the kidney. This diagnosis should be discussed when a renal mass occurs in a context of malformative uropathy and xanthogranulomatous pyelonephritis have to be included in the differential diagnosis of renal mass in infants and children.