Case 1:
A 6-year-old male was referred to the emergency department of Mofid children's Hospital with complaints of abdominal pain and vomiting in the 2020 late spring.
The case was under follow-up due to congenital hydronephrosis in our nephrology clinic. On neonatal ultrasonography, the APD of the renal pelvis was 13mm on the right and 12mm on the left. The blood pressure, renal function tests, urinalysis, and voiding cystourethrography (VCUG) were normal. The APD had gradually decreased to 6mm on the right and 5 mm on the left at 5 years of age (6 months before the last admission) in our serial follow-ups together with a normal bladder appearance and post-voiding residual volume.
On admission, the weight was 22 kg (65% percentile) and blood pressure was 100/60 mmHg.. On physical examination, there was mild generalized abdominal and right costovertebral angle tenderness and there was no fever or evidence of a respiratory or another gastrointestinal problem.
The hemoglobin level was 12.8 g/dl and C-reactive protein (CRP) was in the normal range and urinalysis showed 3–4 RBCs with no WBC or protein.
Abdominal ultrasonography was performed on the first day of admission which showed the size of the kidneys to be 108 mm on the right and 80 mm on the left and a severe hydronephrosis on the right with APD of 35mm. The APD of the left kidney and the echogenicity of both kidneys were normal. The ultrasonography of the urinary tract was repeated after 2 days and on the last imaging, the APD increased to 45 mm while clinically abdominal pain persisted without any localized tenderness during this time.
Spiral abdominopelvic computerized tomography (CT) scan showed the same findings on ultrasonography without detection of urolithiasis. TC-99m Diethylenetriamine pentaacetate (DTPA) scan showed obstructive hydronephrosis on the right kidney.
The patient underwent surgery due to symptomatic obstruction and the findings during surgery were moderate obstruction and marked inflammation at the ureteropelvic junction (UPJ) without complete obstruction. He became febrile the day following the surgery and the evaluations showed a positive CRP and also a positive polymerase chain reaction (PCR) test for the COVID-19 virus.
The chest CT scan showed the characteristic pulmonary involvement in favor of COVID-19 infection. The patient was transferred to the COVID-19 ward and was discharged after one week with a good general condition.
On the day of discharge, the ultrasonography showed mild hydronephrosis with an RPD of 8 mm and also normal laboratory tests and blood pressure.
The patient was followed quarterly for one year and showed no abnormal clinical or laboratory findings.
Case 2:
A 13-month-old female was referred to the outpatient clinic of our hospital with complaints of mild fever and abdominal pain in February 2020. Urinalysis and urine culture were done due to a prior history of prenatal mild hydronephrosis with stable clinical course. Urine analysis showed pyuria and oral cefixime was prescribed with a presumed urinary tract infection diagnosis. The patient became afebrile within two days and began to develop diarrhea and vomiting. Further evaluations showed a positive PCR test for COVID-19. The patient underwent abdominal ultrasonography which reported a severe degree of hydronephrosis.
The patient underwent pyeloplasty due to the uptake defect on DMSA (Dimercaptosuccinic acid) scan, signs of obstruction in DTPA scan, and exacerbation of hydronephrosis after the recovery period of COVID-infection.
Case 3:
A 3-year-old female was followed up due to a history of mild hydronephrosis and anti-reflux surgery at one year of age. She had no history of UTI and was quite stable clinically with only mild unilateral hydronephrosis on renal ultrasonography two months before referral in July 2020.
She was referred due to fever for a few days and was admitted with a presumed diagnosis of UTI due to pyuria and proteinuria in urinalysis. On repeat ultrasonography, severe hydronephrosis was detected in the ipsilateral kidney and on the DMSA scan a severe uptake defect of the hydronephrotic kidney was detected. In recent history the child had exposure to a case of COVID-19 one week before admission.
Case 4:
The patient was a 6-year-old female who was under follow-up due to prenatal hydronephrosis and one episode of UTI. There was no evidence of vesicoureteral reflux in her infantile evaluation.
Pyeloplasty was done at one year of age due to the obstructive pattern on the DTPA scan. At her postsurgical follow-up, the APD in renal ultrasonography was normal and the clinical course was stable.
Three months after the last visit (in November 2020) she was referred to our outpatient clinic due to occasional complaints of abdominal pain and anorexia. In the first evaluation urinalysis was normal and on ultrasonography, a severe degree of hydronephrosis was reported. The past medical history revealed infection with COVID-19 a week before referral.
DTPA scan showed a non-obstructive pattern despite the severe hydronephrosis.
The patient is now under follow-up with decreasing APD in serial ultrasonography and normal clinical and laboratory data.
Case 5:
The case was a 5-year-old male who was under follow-up due to bilateral hydronephrosis from birth. There was no history of UTI and no evidence of vesicoureteral reflux in the neonatal evaluation. Her evaluation in infancy showed a non-obstructive pattern on DTPA scan and serial follow-up revealed improving course bilaterally.
Six months before the last visit, renal function tests, urinalysis, and blood pressure were normal and the renal ultrasonography showed an improving trend of hydronephrosis.
On the last visit in May 2021, kidney ultrasonography showed a marked bilateral increase in APD despite stable clinical course and the history revealed infection with COVID-19 virus one month before referral. A DTPA scan was ordered and is being awaited.