An unusual case of a giant vesico–urethral calculus in a Developing country: A case report

Case report

A 63-year-old man from a rural area in the stone belt of Northwest India presented with urine leakage surrounding his suprapubic catheter (SPC) (in situ for the last eight years). He also had soreness of the surrounding skin (for the last quarter) and chronic multi-species urinary tract infections (Pseudomonas, Klebsiella, Staphylococcus), which were not responding to oral antibiotics. His past history included repeated interventions for bulbomembranous urethral strictures and bladder neck obstruction which resulted in urinary incontinence. Patient opted for permanent SPC drainage.

On examination, the catheter was draining slightly turbid urine with leakage and skin excoriation as previously described. Suprapubilc dullness and mild tenderness were elicited on percussion. Routine investigations including renal function tests were normal. Urine analysis revealed a pH of >7 with a few leucocytes. The culture grew Klebsiella (a urea-splitting organism). A plain abdominal radiograph showed a large radio-opaque shadow in the pelvis extending behind the pubic symphysis along with a displaced Foley's catheter [Fig. 1(a)]. On ultrasonography, both upper urinary tracts were normal. Computed tomography 3-D reconstruction confirmed a giant vesical calculus (900 Hounsefield units’ density) with posterior urethral extension [Fig. 1(b)]. Suprapubic vesico-lithotomy under cover of parentral antibiotics was performed. The stone was gently extracted en bloc with the help of a sponge holding forceps from above and simultaneous digital rectal manipulation from below. Post-operative cystopanendoscopy revealed complete stone clearance with a normal urethra, prostate and an open irregular bladder neck. 16 Fr foleys catheter kept indwelling. The stone measured 140 × 76 × 47mm, weighed 250g and its cut section showed multiple layers of mineral deposit [Fig. 2(a),(b)]. Fourier transform infrared spectroscopy of the stone reported a composition of Magnesium Ammonium Phosphate (MgNH4PO4) Hexahydrate 80% and Carbonate Apatite 20%. On follow-up after 2 weeks, patient was catheter-free and voiding satisfactorily with urine culture showing no growth of organisms. Our patient was administered antibiotic prophylaxis, abundant oral fluids (to have urine output of 2 liters/day), and a limited protein (65g), sodium (2g) and phosphorus diet. To help acidification of urine, NH₄Cl (pH5–6) and Ascorbic acid (pH < 3) was prescribed.

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Figure 1.

(a) KUB Xray showing vesico-urethral stone and suprapubic catheter (↑ ). (b) CT scan (Sagittal Section) 3D reconstruction of stone. KUB: kidney, ureter, and bladder; CT: computed tomography.

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Figure 2.

(a) Post-op stone specimen on weighing scale. (b) Cut section showing layers of mineral deposit.

Discussion

Iatrogenic bladder neck incompetence, long-term suprapubic catheterization and its complications contribute to formation of vesico-urethral calculi Giant struvite calculi (>100 g by weight ¹ ) are rare in modern urological practice. Major risk factors in this patient were dehydration, working in hot (43°C) and semi-arid weather with lack of water facility in the fields. Struvite stone is crystalline mineral which grows rapidly in multiple layers in the presence of urea-splitting organisms. Antibiotics alone are not effective. Open surgery is the recommended modality of treatment. Other risk factors are illiteracy, ignorance, lack of adequate health care facility ² leading to infrequent catheter change. Hence counselling of the patient in this regard is very important.