Antibiotic treatment of urinary tract infections.Urine microscopy: rectangular prisms (coffin lid-appearance) indicate struvite stones.Use of indwelling catheter increases risk.Can form very large stones that fill the entire renal pelvis and calyces ( staghorn calculi).These bacteria convert urea to ammonia → elevated ammonia causing alkaline urine → precipitation of the ammonium magnesium phosphate salt → crystal and stone formation.Upper UTI with urease-producing bacteria such as Proteus mirabilis, Klebsiella, Staphylococcus saprophyticus, and/or Pseudomonas.Struvite stones ( magnesium ammonium phosphate stones) U ric acid stones are radiol Ucent ( x-ray negative). Uricosuric agents (e.g., probenecid) increase the excretion of uric acid, which can accelerate the formation of stones. Oral chemolitholysis (e.g., potassium citrate ) via urine alkalinization.US and/or intravenous pyelogram may also be helpful in diagnosis.CT: can be visible but are usually only minimally visible (not as visible as calcium stones).Urine microscopy: rhomboid/ needle-shaped crystals.↓ Urine volume, e.g., due to dehydration ( often seen in desert climates ).High cell turnover (e.g., tumor lysis syndrome, myelodysplastic syndrome).Urine alkalinization (e.g., with potassium citrate)Ĭrohn disease leads to increased oxalate absorption via malabsorption of fatty acids, which can ultimately cause nephrolithiasis.Thiazide diuretics for recurrent calcium -containing stones with idiopathic hypercalciuria (i.e., no hypercalcemia ).Calcium intake should not be restricted (restriction increases risk of hyperoxaluria, and thereby, the risk for osteoporosis).Reduced intake of oxalate-rich foods and supplemental vitamin C.Reduced intake of salt (mainly sodium) and animal protein.Urine microscopy: dumbbell-shaped or octahedron-shaped crystals.Hyperuricosuria: increased urinary excretion of uric acid.Hypocitraturia : decreased level of citrate in the urine.In conditions associated with fatty acid malabsorption due to impaired bile acid reabsorption, calcium preferentially binds free fatty acids, leading to excess free oxalate and, therefore, to increased oxalate absorption.Calcium normally binds oxalate to form calcium oxalate, which is excreted via feces.Increased intestinal absorption of oxalate, e.g., due to fatty acid malabsorption (e.g., Crohn disease, ulcerative colitis, short bowel syndrome).Hyperoxaluria : presence of elevated oxalate levels in the urine.Hypercalciuria : presence of elevated calcium levels in the urine.Calcium oxalate dihydrate (weddellite): light yellow calculi.Calcium oxalate monohydrate (whewellite): brown or black calculi.Rectangular prisms ( coffin lid-appearance ).UTI with urease-producing bacteria (e.g., Proteus mirabilis, S.Rounded rhomboids, rosettes, or needle-shaped.↓ Urine pH (acidic) and volume (often seen in desert climates).High cell turnover (e.g., leukemia, chemotherapy).Gout, hyperuricemia, and hyperuricosuria.Biconcave dumbbells or bipyramidal envelopes.Associated with inflammatory bowel disease, i.e., ulcerative colitis and Crohn disease due to malabsorption.In addition, the analysis of passed stones may provide information to guide dietary changes and/or medical therapy (e.g., thiazide diuretics, urine alkalinization) that can prevent future stone formation. The most important preventive measure is adequate hydration. If spontaneous passage appears unlikely or fails because of the size or location of the stone, first-line urological interventions include shock wave lithotripsy, ureterorenoscopy, and, in patients with large kidney stones, percutaneous nephrolithotomy. Small stones that do not require urgent urological intervention can be managed with symptomatic treatment and a trial of medical expulsive therapy to promote spontaneous passage. Diagnostics include spiral CT without contrast and/or ultrasound of the abdomen and pelvis to detect the stone, as well as urinalysis to assess for concomitant urinary tract infection ( UTI) and serum BUN and creatinine to evaluate kidney function. Nephrolithiasis manifests as sudden-onset colicky flank pain that may radiate to the groin, testes, or labia, commonly called renal or ureteric colic, and it is usually associated with hematuria. Less common stones are composed of uric acid, struvite (due to infection with urease-producing bacteria), calcium phosphate, or cystine. Urinary stones are most commonly composed of calcium oxalate. Risk factors include low fluid intake and high- sodium, high- purine, low- potassium diets, which can raise the calcium, uric acid, and oxalate levels in the urine and thereby promote stone formation. Nephrolithiasis encompasses the formation of all types of urinary calculi in the kidney, which may be deposited along the entire urogenital tract, from the renal pelvis to the urethra.
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