Nephrolithiasis in medullary sponge kidney: evaluation of clinical and metabolic features.

OBJECTIVE: Medullary sponge kidney (MSK) is a disorder characterized by tubular dilation of renal collecting ducts and cystic dilation of medullary pyramids that has been associated with stone disease. The significance of nephrolithiasis and the mechanisms by which it occurs are incompletely understood. We describe clinical and metabolic features of nephrolithiasis in a cohort of patients with MSK. METHODS: Records were reviewed of 56 patients, all with radiographic diagnosis of medullary sponge kidney and data collected pertaining to presentation, stone events and recurrences, stone composition, and metabolic profile to perform a descriptive study with median 3.7 years follow-up. RESULTS: Nephrolithiasis was confirmed radiographically in 39/56 patients (69.6%). No patient without evidence of nephrolithiasis developed a stone event, whereas 13/39 (33%) of those with nephrolithiasis developed a recurrent stone event. Stones were composed of calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate apatite, and uric acid. Metabolic profile was obtained for 26 of 39 (67%) stone-forming patients demonstrating abnormalities in 22/26 (84.6%). These included hypercalciuria, 58% (15/26); low urine volume, 35% (9/26); hyperuricosuria, 27% (7/26); hypocitraturia, 19% (5/26); elevated urine sodium, 15% (4/26); and hyperoxaluria, 12% (3/26). CONCLUSION: Many patients with MSK have no evidence of nephrolithiasis. Among those who do, recurrence is common, and metabolic profile and composition are varied as in the general stone-forming population.

MRI and its role in the evaluation and surgical decision making in patients with challenging IPP presentations: descriptions of MRI findings and algorithm for patient management.

UNLABELLED: Study Type - Diagnostic (case series) Level of Evidence 4 What's known on the subject? and What does the study add? It is known that magnetic resonance imaging (MRI) is safe and effective for imaging patients with inflatable penile prostheses (IPPs). Previous series have reported results of MRI for imaging series of patients with IPPs. The impact on management in particular with regard to salvage procedures is not well defined. This study represents the largest known experience with MRI evaluation of IPPs. This also provides an algorithm that assists with decisions regarding utilization of MRI and treatment planning based on results. OBJECTIVE: • In some patients who undergo placement of an inflatable penile prosthesis (IPP) the device may function inadequately. We describe the use of magnetic resonance imaging (MRI) for anatomical localization and detection of prosthesis malrotation, angulation, displacement and erosion in IPPs with equivocal clinical examination. PATIENTS AND METHODS: • We prospectively performed MRI by a defined protocol including T1-weighted imaging, and transaxial, sagittal and coronal fat-saturated fast spin-echo T2-weighted imaging in both deflated and inflated states to evaluate patients seen at our referral centre for IPP-related complaints. • We retrospectively reviewed 32 such MRI studies performed as a supplement to clinical examination between 2000 and 2008. RESULTS: • Of 32 cases, 75% (24/32) underwent surgical intervention. Of these, 45% (11/24) underwent device salvage procedures including cylinder revision in 33% (8/24), cylinder replacement in 8% (2/24) and pump replacement in 4% (1/24). • MRI was most useful for determination of surgical approach in those with abnormal physical examination, and for justification of either surgical or expectant management in those with indeterminate physical examination. CONCLUSIONS: • MRI is safe and effective for imaging genitourinary prostheses. • We found MRI to be a valuable adjunct for evaluation of IPP-related complaints when clinical examination is equivocal as it detected a variety of prosthetic and corporal abnormalities and impacted management decisions regarding observation, replacement or device salvage procedures. • We provide technique, results and an algorithm that can be beneficial in this complex subset of patients.