Primary Vaginal Stones in an 11-Year-Old Girl

Primary vaginal stones are very rare and typically arise from the stasis of urine in the vagina or as a result of an anatomical defect (e.g. fistula). In children without anatomical defects, vaginal stones are usually formed following crystallization around a foreign body [1]. In our case, even though no fistula was seen on examination, the stone was considered to be primary because analysis of the stone helped eliminate the possibility of a foreign body. In young girls, diagnosis and removal of such stones are challenging, but utilization of vaginoscopy for diagnosis and, with the aid of a nephroscope, disintegration using a lithotripsy device are effective [2]. We describe an 11-year-old girl with vaginal stone who presented with recurrent urinary tract infections and continuous urinary incontinence.


Introduction
Primary vaginal stones are very rare and typically arise from the stasis of urine in the vagina or as a result of an anatomical defect (e.g.fistula).In children without anatomical defects, vaginal stones are usually formed following crystallization around a foreign body [1].In our case, even though no fistula was seen on examination, the stone was considered to be primary because analysis of the stone helped eliminate the possibility of a foreign body.In young girls, diagnosis and removal of such stones are challenging, but utilization of vaginoscopy for diagnosis and, with the aid of a nephroscope, disintegration using a lithotripsy device are effective [2].We describe an 11-year-old girl with vaginal stone who presented with recurrent urinary tract infections and continuous urinary incontinence.
• Ultrasonography of abdomen demonstrated no dilatation of the kidneys and a bladder void of urine.
• No sign of reflux was detected on a voiding cystogram and renal function appeared normal.
• Ultrasound of the pelvis was limited because of an inability to fill the bladder.
• A computed tomography scan revealed a highly calcified mass behind the urinary bladder measuring 5 × 6 cm, but was otherwise normal.
• A cystometrogram showed normal bladder capacity and contractility.Thus, laparotomy was offered with the intent of incising the bladder and removing the mass.However, no bladder stones were identified during the procedure, but the urethra appeared to be short and wide, and pulled backward and upward by a mass-like structure behind the bladder trigone.A methylene blue dye test was performed and excluded a fistula (the dye did not appear in the vagina when instilled in the bladder).
During an examination of the rectum, two apparently mobile stones were palpated in the vagina.No structural anomalies of the vulva or hymen were detected.Vaginoscopy identified a large stone, which precluded removal due to its size and hardness.A second intervention was scheduled after intra operative consultation with a urologist, who inserted a double J catheter for retrograde pyelography the following day; the results of this study were normal (Figure 3).The patient's parents were informed, and a different approach was suggested for the second procedure.After general anesthesia, a small nasal speculum was used to examine the vaginal stones.The stones were then successfully disintegrated using pneumatic lithoclast, and the fragments were extracted completely and sent for analysis.No mass was palpable after repeated digital examination.Successive examinations demonstrated an intact vaginal wall and the absence of stones in the vagina.Stone analysis revealed a calcium oxalate composition.The patient's pressure symptoms completely disappeared,

Discussion
This report describes a case of primary vaginal stones diagnosed in an 11-year-old girl.Primary vaginal stones are caused by several factors, including anatomical defects, neurogenic diseases affecting bladder and urethral function, vaginal obstructive lesions (e.g.stricture, septum), prolapse of anterior vaginal wall (e.g.cystocele), urethral diverticulum and genitourinary system anomalies (e.g.ectopic vaginal ureter); primary stones may also be seen in association with obstructive uterine anomalies [3][4][5][6].
No genitourinary tract abnormalities were detected on initial examination of the patient, but the definitive diagnosis was based on examination under anesthesia and endoscopic examination.A vesicovaginal fistula was excluded by urethrocystoscopy and instillation of methylene blue into the bladder.Because the patient's hymen was intact, it was unlikely that her symptoms were due to the presence of a foreign body in the vagina.
Neurological disease was excluded since the patient had normal intellectual development and was continent for gas and stool.In general, the pooling of urine in the vagina is due to incontinence, whereas vaginal stones can be formed as a result of infection following contamination of the urine with stool.Urease-producing bacteria appear to be a major factor of stone formation in the vagina [7].These bacteria change the normally acidic pH of the vagina to an alkaline pH, consequently increasing the risk of stone formation (specifically triple phosphate calculi).However, in this case, analysis showed a different stone composition.The comparatively low levels of estrogen in prepubertal girls and postmenopausal women can also cause an alkaline vaginal pH due to the absence of lactic acid, which may increase an individual's risk of developing infections due to urease-producing bacteria [8][9][10].Young patients might also benefit from nephroscopy when vaginoscopy is recommended.Moreover, in cases where instrumentation is needed, nephroscopy can provide further benefits.In prepubertal girls, a better panoramic view of the vagina can be obtained by using a vaginoscope with an irrigating endoscope (such as a nephroscope) compared to a nasal speculum.
Shock wave lithotripsy has been demonstrated to be beneficial in stone breakage.However, it is thought that therapeutic ultrasound can cause soft tissue damage through driving bubble activity [11].One area that has been extensively studied is the role of cavitation in both natural and artificial kidney stones.In fact, it is thought that cavitation bubble activity helps in the stone breaking process, and findings from previous studies suggest that these bubble interactions contribute to the tissue injury that occurs during shock wave treatment [12][13][14].In one report [15], investigators used high-speed photography to demonstrate that cavitation helped in stone fragmentation through erosion and pitting.Further, they suggested a possible link between cavitation bubble cluster activity and the formation of fractures in kidney stones in shock wave treatment.
Overall, primary vaginal stone is a rare finding in prepubertal girls, and it is probably caused by the interaction of several factors, including urinary stasis, contamination with stool, and chronic infection.A nephroscope and vaginoscopy might be beneficial in visualizing the vagina in prepubertal patients.As demonstrated in our case, vaginal stones can be disintegrated and safely removed using a pneumatic lithoclast.

Figure 1 :Figure 2 :
Figure 1: Pelvic ultrasound imaging: Normal size and shape of uterus with pressure effect from highly calcified mass at the level of vagina of unknown origin