Xanthogranulomatous pyelonephritis in children: diagnostic and therapeutic aspects

A pediatric case of xanthogranulomatous pyelonephritis in the setting of Covid-19 and multi-system inflammatory syndrome (MIS-C)

Xanthogranulmatous pyelonephritis is a rare, chronic inflammatory pathology of the kidney. It most commonly arises in middle-aged females, but there are case reports and series described in the pediatric population. Here, we discuss the case of a 14 year old male who presented with xanthogranulomatous pyelonephritis in the setting of Covid-19 and multi-system inflammatory syndrome (MIS-C). As xanthogranulomatous pyelonephritis often mimics other diseases that are more prevalent in the pediatric population, our case was only definitively diagnosed with histopathology after surgical resection. This report is novel in that, to our knowledge, it is the first to describe xanthogranulomatous pyelonephritis in the setting of MIS-C.

Xanthogranulomatous pyelonephritis in a pediatric patient

Introduction:

Xanthogranulomatous pyelonephritis consists of a chronic infectious and inflammatory process of the renal parenchyma, a variant of chronic obstructive pyelonephritis. It is more prevalent in middle-aged adults, rare in pediatric patients, with less than 300 cases reported in children worldwide.

Report:

Preschooler, aged 2 years and 11 months, male, with 2 months of abdominal distention, increased temperature and intense pallor, associated with microcytic anemia refractory to the use of ferrous sulfate. 1 week before, he had a bulging in his left flank and a hard palpable mass there. Imaging exams (ultrasound and tomography) revealed an overall enlargement of the left kidney, destruction of the renal parenchyma and intense calyceal dilation, forming the "bear's paw" sign, with a staghorn calculus in the pelvis. He underwent treatment with antibiotic therapy and total nephrectomy, with a specimen sent for pathological examination.

Discussion:

a disease of uncertain incidence in the pediatric age group, xanthogranulomatous pyelonephritis is more prevalent in male children and affects mainly the left kidney, being frequently associated with the presence of stones. Clinically, it has nonspecific symptoms, the most common being abdominal distension and asthenia. Laboratory exams shows microcytic, leukocytosis, thrombocytosis and increased inflammation, pyuria, hematuria and proteinuria, in addition to bacterial growth in urine culture. The diagnosis is anatomopathological, but it can be hinted by contrasted CT scan, with the classical sign of the "bear's paw". Treatment may include nephrectomy and broad-spectrum antibiotic therapy.

Xanthogranulomatous pyelonephritis in a paediatric cohort (1963-2016): Outcomes from a large single-center series

BACKGROUND

Xanthogranulomatous pyelonephritis (XGP) is an uncommon chronic destructive granulomatous inflammation of the kidney. It was first described in 1916, and is thought to affect 6/1000 cases of pyelonephritis. Its manifestations are varied, and with a limited number of cases in the literature, the optimal diagnosis and management of XGP in the paediatric cohort is still unknown.

MATERIAL AND METHODS

The medical records of children who were diagnosed and treated for XGP at the current unit during the period 1963-2016, inclusive, were retrospectively reviewed. Information pertaining to each patient was recorded, including: demographic data, past medical history, clinical and biochemical characteristics, diagnostic procedures, treatment methods, histopathologic diagnosis of the removed specimen, and outcome.

RESULTS

A total of 66 children with a median age of 4.84 years (range 1.1-14.81), with an M:F ratio 1.35:1 underwent nephrectomy for XGP and had a median follow-up of 7.19 years (range 0.11-17.45). The most common presentations were systemic illness (62.1%), pain (60.6%), urinary tract infections (54.5%) and an abdominal mass (39.4%); pyrexia was present in 53%. Biochemical abnormalities included anaemia (86.3%), thrombocytosis (80.3%) and hypomagnesemia (65.1%). There was an 83.3% concordance between intraoperative cultures and positive mid-stream urines. Index kidneys were significantly larger than the contralateral side (mean 1.32 cm; P = 0.002). Staging of XGP demonstrated extension beyond the kidney in 79% of kidneys. Computed tomography (CT) was performed in 11 cases (Summary figure). Dimercaptosuccinic acid (DMSA) scan showed 0-10% function in 90.47% of cases. Surgical procedures included nephrectomy (n = 63) and partial nephrectomy (n = 3). Perioperative complications included colonic resections (n = 5) and abscess formation in 18%.

CONCLUSIONS

This is the largest series to date of XGP in a paediatric cohort. XGP should be included in the differential diagnosis of all children presenting with perirenal or psoas abscesses, renal masses and/or non-functioning kidneys with/or without associated urolithiasis. Clinical awareness and a high index of suspicion is required to achieve the correct pre-operative diagnosis and appropriate management.

Girl with xanthogranulomatous pyelonephritis and bronchiectasis: case report

Xanthogranulomatous pyelonephritis (XGP) is a rare chronic inflammatory disorder of the kidney. Infiltration to lung and liver can occur. We present a rare complication of locally invasive XGP extending beyond the diaphragm to the lung to cause bronchiectasis in an adolescent girl with chronic productive cough, weight loss and no urinary symptoms. The patient underwent open left radical nephrectomy, where it was noted that the left kidney lay very high with significant perinephric inflammation and was densely adherent to the diaphragm and partially adherent to the spleen. XGP was confirmed on histology.

Xanthogranulomatous pyelonephritis presenting with thrombocytopenia and renal mass

Xanthogranulomatous pyelonephritis (XGP) is a rare event in children without any predisposing factor like calculi, obstruction or vesicoureteral reflux. In this case we report a four-year-old girl who presented with a renal mass, hematuria, flank pain, anemia and thrombocytopenia—these signs and symptoms misled us to Wilms tumor. Thrombocytopenia which is a strange event in XGP resolved after nephrectomy. Normal contra lateral kidney was infected four months after right nephrectomy. This suggests that these patients should be under strict surveillance and antibiotic prophylaxis as they are a high-risk group for urinary tract infection, and thrombocytopenia should be considered as a laboratory test finding in XGP.