Kidney Stone

Kidney stone Classification and external resources A kidney stone, 8 millimeters (0.31 in) in diameter ICD- 10 N 20.0– N 20.9 ICD- 9 592.0, 592.1, 592.9 DiseasesDB 11346 MedlinePlus 000458 eMedicine med/1600 MeSH D007669 Akidney stone, also known as arenal calculus(from the Latinrēnēs, "kidneys," and calculus, "pebble"), is a solid concretionor crystalaggregation formed in the kidneys from dietary mineralsin the urine. Urinary stonesare typically classified by their location in the kidney(nephrolithiasis), ureter(ureterolithiasis), or bladder( cystolithiasis), or by their chemical composition( calcium-containing, struvite, uric acid, or other compounds). About 80% of those with kidney stones are men. Kidney stones typically leave the body by passage in the urine stream, and many stones are formed and passed without causing symptoms. If stones grow to sufficient size (usually at least 3 millimeters (0.12 in)) they can cause obstruction of the ureter. Ureteral obstruction causes postrenal azotemiaand hydronephrosis(distension and dilation of the renal pelvisand calyces), as well as spasmof the ureter. This leads to pain, most commonly felt in the flank(the area between the ribs and hip), lower abdomen, and groin(a condition called renal colic). Renal colic can be associated with nausea, vomiting, fever, blood in the urine, pusin the urine, and painful urination. Renal colic typically comes in waves lasting 20 to 60 minutes, beginning in the flank or lower back and often radiating to the groin or genitals. The diagnosisof kidney stones is made on the basis of information obtained from the history, physical examination, urinalysis, and radiographicstudies. Ultrasound examinationand blood testsmay also aid in the diagnosis. When a stone causes no symptoms, watchful waitingis a valid option. For symptomatic stones, pain controlis usually the first measure, using medications such as nonsteroidal anti-inflammatory drugsor opioids. More severe cases may require surgical intervention. For example, some stones can be shattered into smaller fragments using extracorporeal shock wave lithotripsy. Some cases require more invasiveforms of surgery. Examples of these are cystoscopicprocedures such as laser lithotripsyor percutaneoustechniques such as percutaneous nephrolithotomy. Sometimes, a tube ( ureteral stent) may be placed in the ureter to bypass the obstruction and alleviate the symptoms, as well as to prevent ureteral stricture after ureteroscopic stone removal. Signs and symptoms Diagram showing the typical location of renal colic, below the rib cage to just above the pelvis The hallmark of stones that obstruct the ureter or renal pelvis is excruciating, intermittent pain that radiates from the flank to the groin or to the inner thigh. [ 1 ]This particular type of pain, known as renal colic, is often described as one of the strongest pain sensations known. [ 2 ]Renal colic caused by kidney stones is commonly accompanied by urinary urgency, restlessness, hematuria, sweating, nausea, and vomiting. It typically comes in waves lasting 20 to 60 minutes caused by peristalticcontractions of the ureter as it attempts to expel the stone. [ 1 ]The embryologicallink between the urinary tract, the genital system, and the gastrointestinal tractis the basis of the radiation of pain to the gonads, as well as the nausea and vomiting that are also common in urolithiasis. [ 3 ] Postrenal azotemiaand hydronephrosis can be observed following the obstruction of urine flow through one or both ureters.