Teaching Case

A 53-year-old female patient was referred for evaluation of lower abdominal pain which was non-radiating. She gave history of difficulty in passing urine and burning micturition not associated with haematuria. She denied history of IUCD usage or foreign body insertion into urethra.

KUB radiograph revealed a radiodense rounded structure in the region of the bladder with laminations in the periphery. Further evaluation of the pelvis by ultrasound showed a curvilinear echogenic structure in the bladder lumen showing twinkling artefact on colour doppler. There was also left moderate hydroureteronephrosis with internal echoes in bladder lumen suggestive of cystitis.

Bladder calculi have been subclassified into 3 categories- Migrant, Primary endemic and Secondary. Migrant variety is the commonest, where it has formed in the kidney and then moved down through the ureter into the bladder. Primary endemic calculi are seen in children and young adults in developing and under-developed countries secondary to dietary constraints. Secondary calculi are seen in adults as a result of urinary stasis. In men, it’s mostly due to urinary obstruction from enlarged prostate and in women secondary to a cystocele. Patients with neurogenic bladder are also at risk for developing bladder calculi. An uncommon but well-documented cause of secondary bladder calculi includes encrustation of foreign bodies. [1, 2, 3]
Foreign bodies maybe introduced into the bladder either for medical purposes such as bladder catheter, ureter stent or by the patients themselves in cases of psychiatric illness or for sexual pleasure. Traumatic introduction of intravesical foreign body has been well documented such as bullets, Intra-Uterine Contraceptive Devices (IUCD), etc. The mechanism of uterine perforation by an IUCD is closely related to time & technique of insertion, type of IUCD, skill of the doctor and female genitourinary anatomy. Migration of a uterine IUCD into the bladder can also be caused by uterine or bladder contractions. [3, 4, 5]
Most patients with bladder calculi are asymptomatic, but they can present with urinary obstruction, abdominal pain or renal colic or recurrent urinary tract infection.[4, 5]
On plain KUB radiographs, bladder calculi may appear as radiodense structures. On excretion cystography or urography they cause filling defects, while ultrasound will show echogenic mobile structures with posterior acoustic shadowing and twinkling artifact on colour doppler. Irrespective of its composition bladder calculi are well appreciated on CT, except for drug related stones (e.g. Indinivir stones) which are lucent on all imaging modalities.[2, 3]
Bladder calculi range in size from a few mm to 4 cm. Our patient's calculus was approx. 7 cm. Though the exact aetiology is not known, we assume it was probably due to an earlier undetected calculus or due to chronic urinary stasis with concentrated urine leading to stone formation. Known complications associated with large bladder calculus include- haematuria, cystitis, acute renal failure, spontaneous bladder rupture and increased risk for bladder cancer. Our patient underwent open surgery (cystolithotomy) due to the large size of the calculus, and was discharged with stable vitals.[6-10]