Urolithiasis-related ureteric intussusception: A rare case report

Ureteral intussusception is a rare condition that historically occurs as a complication of ureteral neoplasms or iatrogenic endoscopic procedures. Although the exact mechanism of ureteral intussusception is unclear, most reported cases are due to leading points as malignant or benign masses. Urolithiasis related is rarely reported and can be challenging in stone management as it might decrease the spontaneous stone passage rate. In addition, it will increase the complexity of the endoscopic stone management. We present the second reported case of urolithiasis-related ureteric intussusception presented with urosepsis due to obstructive uropathy, successfully managed by an endourological approach.


Introduction
Ureteral intussusception is a rarely reported condition; the majority of reported cases are related to different variants of urological benign and malignant tumors, with the least of the cases being secondary to iatrogenic surgical complications.][4] We present a case of an infected and obstructed kidney that was eventually found to be associated with ureteral intussusception related to urolithiasis.

Case presentation
69 years old lady known hypertensive and diabetic, controlled on medications, with a past medical history of small bilateral renal calculi on conservative treatment presented to our emergency department complaining of severe right flank pain and vomiting that was associated with fever, chills alongside dysuria, and urgency for four days.She was febrile initially, with a temperature of 38.1 c.Workup revealed elevated inflammatory markers with positive nitrates and leukocytes in the urine dipstick.Initial US scan was inconclusive; A non-contrast CT scan confirmed the presence of a 10 × 8 mm calculus in the proximal ureter at the level of L4 (Fig. 1).
The patient was admitted and started on intravenous antibiotics, followed by urgent drainage of the right kidney through an emergency percutaneous nephrostomy tube.The urine culture revealed the growth of E. coli ESBL.
After clearing the infection and consulting with the interventional radiology team, the decision was made to intervene retrogradely due to anatomical challenges for antegrade stenting because of abnormal anatomy.
A ureteroscopy was performed.During the procedure, a small stone was seen protruding from the right ureteric orifice, which was removed with forceps, subsequently, a guide wire was advanced up to the right kidney.At that time, a retrograde pyelogram showed a suspicious tortuous upper ureter (Fig. 2).
Upon advancing the ureteroscope, an upper ureteric intussusception was identified in the ureteric tortuosity below the stone (Fig. 3) (video 1) and was reduced using hydrostatic pressure.A second guide wire was fixed.However, as the stone retropulsed higher, a ureteric access sheath was introduced, followed by a flexible ureteroscope.The stone was fragmented, a stent was left in situ, and the patient was discharged in stable condition.
After one week, the stent was removed during the clinic follow-up, and her subsequent contrasted CT abdomen, after six weeks, revealed only a tiny small renal stone; however, there was no recurrence of the intussusception and no hydronephrosis was observed.During her regular follow-ups, the last US scan showed total clearance of all renal stones and the absence of hydronephrosis.

Discussion
Ureteral intussusception is a rare condition, as the ureter anatomy * Corresponding author.
Contents prevents ureteric invagination due to multiple variables resulting from the small ratio between ureteral wall thickness, limited range of mobility, and lumen caliber. 5][4] The proposed mechanism of urolithiasis-related intussusception is that a non-obstructive ureteric calculus remains in the ureter for an extended period, causing ureteric inflammation.The calculus adheres to the wall of the ureter, and the combination of the antegrade flow of urine, ureteric peristalsis, and gravity pulls the stone in an antegrade direction.As the calculus moves antegrade, it draws on the adherent inflamed ureter, causing intussusception of the ureter, with the intussusceptum containing the calculus and inflamed ureter. 1 In our case, infection added to the inflammation contributed to intussusception development.
Patients typically present with complaints of hematuria and flank pain.However, it's not universal, as malignant tumors related to ureteric intussusception are often asymptomatic. 5Radiological studies helped in diagnosing especially intravenous urography and Contrast CT scan, they demonstrate the primary lesion for intussusception as a filling defect in an enlarged ureteral segment with or without hydronephrosis presenting as a "Stalk -of -corn ". 5 Management of ureteral intussusception as a complication of chronic ureterolithiasis differs from treatment in the presence of a tumor.As previously reported, cases have been treated with various surgical options, including nephroureterectomy, primary resection and reanastomosis, boari flap, [1][2][3][4][5] and, in a unique case, by ileal interposition. 3 On the other hand, when suspecting a urolithiasis-related intussusception, the ureteroscope is a powerful option for diagnostic and definitive management at the same time, as in our case, the retrograde pyelogram showed suspicious tortuous upper ureter that was confirmed under direct vision, to be a ureteral intussusception, as there was no endoscopic signs of urothelial malignancy, constant hydrostatic pressure and placing two guide wire succeed to straightening the ureter.Additionally, placing a ureteral sheath to clear the stone and avoid using of basket followed by placing double J stent helped in preventing the recurrence of the intussusception.

Financial disclosure
All the authors declare that they do not have any conflict of interest with the subject of this article.

Fig. 3 .
Fig. 3. Ureteroscopy showed an intussuscepted ureter with a wire passing into the lumen of the intussusceptum, To the renal pelvis in the ureteric lumen.