Urolithiasis

Urolithiasis is the presence of stones in the urinary tract - in the renal pelvis (nephro-), ureter (uretero-), bladder (cysto-) or urethra (urethrolithiasis) or stone-forming substances in the renal parenchyma (nephrocalcinosis), in our country is the most common calcium oxalate.

Crystallization and aggregation
The causes include:


 * supersaturation of urine with stone-forming substances (Ca2 +, urates, oxalate), supported by reduced diuresis,
 * urinary incontinence (obstructive uropathy),
 * changes in urine pH (incl. urea-degrading bacteria - Proteus, Pseudomonas, Klebsiella - struvite lithia),
 * lack of inhibitors of crystallization and aggregation (citrates, pyrophosphates, Mg2 +, glycoproteins),
 * some drugs (sulfonamides, antacids).

Cystolithiasis occurs in chronic residual subvesical obstruction or neurogenic bladder.

Concretions are divided into:


 * Contrast X-ray - Ca-oxalate, Ca-phosphate, struvite (MgNH4PO3), cystine,
 * Non-contrasting X-ray - urate, xanthine.

Clinical symptoms
Urolithiasis can occur asymptomatically (immobile stones).

Manifesting urolithiasis can be divided according to location into:


 * nephrolithiasis - dull kidney pain (palpation, positive tapottement), ev. how many when blocking the drain,
 * ureterolithiasis - renal colic with vegetative accompaniment, spread according to location (back, inner thigh),
 * cystolithiasis - pain behind the buckle, polakisuria, urgency.

It is often manifested by hematuria and other complications - inflammation (pyelonephritis, cystitis).

Complications
Complications include obstruction - renal colic, hydronephrosis, infection to urosepsis, bleeding and renal insufficiency in bilateral disability.

Diagnostics

 * Urine: sediment, chemically (incl. Cystine), pH, density, culture (negative with complete blockade).
 * Biochemistry: Ca2 +, phosphates, uricaemia, Astrup (exclusion of RTA - renal acidosis).
 * Examination of concretion:
 * chemical,
 * mineralography - polarizing microscope, X-ray distraction,
 * imaging methods:
 * Ultrasound - identification of stones and dilatation of the urinary tract, so-called acoustic shadows can be seen
 * X-ray (native nephrogram, excretory urography), cystolithiasis cystography, cystoscopy,
 * spiral CT,
 * static renal function study (DMSA).


 * Hypercalcaemia, hypercalciuria, hyperphosphaturia - suspected hyperparathyroidism.
 * Urolithiasis with hypokalemia - suspected RTA - renal acidosis.
 * Hypercalciuria - absorption type (↑ resorption of Ca2 + from the intestine) and renal (↓ reverse resorption in the tubules).
 * Hyperoxaluria - a disorder of intestinal fat resorption (chronic pancreatitis, obstructive jaundice).
 * Hyperuricosuria - myeloproliferative diseases, disorders of purine metabolism, chemotherapy.
 * Hypercystinuria - a congenital disorder of renal cystine transport.
 * Hypocitration - chronic diarrhea, administration of thiazide diuretics.

Metabolic examination in urolithiasis

 * Serum: urea, creatinine, uric acid, Na +, K +, Ca2 +, Mg2 +, Cl−, phosphorus, glycemia, total protein, liver tests, cholesterol (LDL, HDL), triglycerides.
 * Urine in 24 hours: volume, urine pH. Wastes in 24 hours: phosphorus, uric acid, creatinine, Na +, K +, Ca2 +, Mg2 +, Cl−, oxalates, citrates, sulphates.
 * Calculations: creatinine clearance, uric acid clearance, Ca2 + / creatinine ratios, Ca2 + / Mg2 +.
 * Proteinuria.
 * Calcium-free diet followed by oral administration of 1000 mg eferv. calcium tablets

Differential diagnostics

 * Pain - sudden abdominal event, biliary colic, gynecological disease.
 * Hematuria - tumor, urinary tract infection, coagulopathy (warfarinization).
 * Defect in the filling of the hollow system - urothelial tumor.

Treatment

 * Acute renal colic:
 * analgesics, antispasmodics, non-steroidal anti-inflammatory drugs (indomethacin National Office for Drug Control: indomethacin),
 * sufficient hydration,
 * supravesical urine derivation with signs of urinary tract infection or urosepsis.


 * Chronic urolithiasis:


 * 1) endoscopic methods,
 * 2) instrumentation - nephrostomy, ureteral probing with extraction or crushing of the stone, cystoscopy with extraction or crushing of the stone - extracorporeal shock wave lithotripsy,
 * 3) open surgery (in about 1%) - lithotomy (pyelo-, uretero-, cysto-), nephrotomy, nephrectomy,
 * 4) conservative treatment - symptomatic treatment of colic, metaphylaxis (prevention of recurrences).


 * Concretion extraction - forceps, Zeiss loop, Dormia basket.
 * Concret crushing - mechanically, ultrasound, electrohydraulic, laser, grinding.
 * Indication:


 * 1) X-ray contrast up to 2 cm made of soft material (weddellite), good anatomical conditions and outflow,
 * 2) stone over 2 cm, hard (whewellite, struvite, Ca-oxalate, urate), unfavorable anatomy and outflow (stenoses),
 * 3) Non-contrast X-ray (cannot be targeted by lithotripter), in the lower 2/3 of the ureter,
 * 4) minor asymptomatic nephrolithiasis, ureterolithiasis up to 4 mm - conservative treatment.


 * Urine pH change:
 * urate stones - alkalization of urine (sodium citrate, potassium citrate),
 * struvite stones - acidification of urine.


 * Metaphylaxis:


 * 1) non-specific - drinking and diet regime (↑ fluid intake, ↓ Ca2 + and salt intake, meat,…),
 * 2) specific - according to the composition of stones - most often citrates, in hyperuricaemia and urate lithiasis allopurinol.