Information of Kidney Stones

 kidney stones :- medicaly its callNephrolithiasis 


Kidney stones are one of the most common urological problems. In the world, APPROXIMATELY 13% of men and 7% of women will develop a kidney stone during their lifetime, and the prevalence is increasing throughout the industrialized world.

Types of Stones

Calcium salts, uric acid, cystine, and struvite (MgNH4PO4) are the basic constituents of most kidney stones in the western hemisphere . Calcium oxalate and calcium phosphate stones make up 75–85% of the total (Table 1) and may be admixed in the same stone. Calcium phosphate in stones is usually hydroxyapatite [Ca5(PO4)3OH] or, less commonly, brushite (CaHPO4H2O).

Table 1 Major Causes of Renal Stones

Stone Type and Causes Percent of all Stonesa
Percent Occurrence of Specific Causesa
Ratio of Males to Females Etiology Diagnosis Treatment
Calcium stones 75–85   2:1 to 3:1      
  Idiopathic hypercalciuria   50–55 2:1 Hereditary (?) Normocalcemia, unexplained hypercalciuriab
Low-sodium, low-protein diet; thiazide diuretics
  Hyperuricosuria   20 4:1 Diet Urine uric acid >750 mg per 24 h (women), >800 mg per 24 h (men) Allopurinol or diet
  Primary hyperparathyroidism   3–5 3:10 Neoplasia Unexplained hypercalcemia Surgery
  Distal renal tubular acidosis   Rare 1:1 Hereditary Hyperchloremic acidosis, minimum urine pH >5.5 Alkali replacement
  Dietary hyperoxaluria   10–30 1:1 High oxalate diet or low calcium diet Urine oxalate >50 mg per 24 h Low oxalate diet
  Enteric hyperoxaluria   1–2 1:1 Bowel surgery Urine oxalate >75 mg per 24 h Cholestyramine or oral calcium loading
  Primary hyperoxaluria   Rare 1:1 Hereditary Urine oxalate and glycolic or l-glyceric acid increased Fluids and pyridoxine
  Hypocitraturia   20–40 1:1 to 2:1 Hereditary (?), diet Urine citrate <320 mg per 24 h Alkali supplements
  Idiopathic stone disease   20 2:1 Unknown None of the above present Oral phosphate, fluids
Uric acid stones 5–10          
   Gout   50 3:1 to 4:1 Hereditary Clinical diagnosis Alkali and allopurinol
  Idiopathic   50 1:1 Hereditary (?) Uric acid stones, no gout Alkali and allopurinol if daily urine uric acid above 1000 mg
  Dehydration   ? 1:1 Intestinal, habit History, intestinal fluid loss Alkali, fluids, reversal of cause
  Lesch-Nyhan syndrome   Rare Males only Hereditary Reduced hypoxanthine-guanine phosphoribosyltransferase level Allopurinol
  Malignant tumors   Rare 1:1 Neoplasia Clinical diagnosis Allopurinol
Cystine stones 1   1:1 Hereditary Stone type; elevated cystine excretion Massive fluids, alkali, D-penicillamine if needed
Struvite stones 5–10   1:3 Infection Stone type Antimicrobial agents and judicious surgery

aValues are percent of patients who form a particular type of stone and who display each specific cause of stones.

bUrine calcium above 300 mg/24 h (men), 250 mg/24 h (women), or 4 mg/kg per 24 h either sex. Hyperthyroidism, Cushing syndrome, sarcoidosis, malignant tumors, immobilization, vitamin D intoxication, rapidly progressive bone disease, and Paget's disease all cause hypercalciuria and must be excluded in diagnosis of idiopathic hypercalciuria.

Calcium stones are more common in men; the average age of onset is the third to fourth decade. Approximately 50% of people who form a single calcium stone eventually form another within the next 10 years. The average rate of new stone formation in recurrent stone formers is about one stone every 2 or 3 years. Uric acid stones account for 5–10% of kidney stones and are also more common in men. Half of patients with uric acid stones have gout; uric acid lithiasis is usually familial whether or not gout is present. Cystine stones are uncommon, comprising ~1% of cases in most series of nephrolithiasis. Struvite stones are common and potentially dangerous. These stones occur mainly in women or patients who require chronic bladder catheterization and result from urinary tract infection with urease-producing bacteria, usually Proteus species. The stones can grow to a large size and fill the renal pelvis and calyces to produce a "staghorn" appearance.

Manifestations of Stones

As stones grow on the surfaces of the renal papillae or within the collecting system, they need not produce symptoms. Asymptomatic stones may be discovered during the course of radiographic studies undertaken for unrelated reasons. Stones rank, along with benign and malignant neoplasms and renal cysts, among the common causes of isolated hematuria. Stones become symptomatic when they enter the ureter or occlude the ureteropelvic junction, causing pain and obstruction.

Stone Passage

A stone can traverse the ureter without symptoms, but passage usually produces pain and bleeding. The pain begins gradually, usually in the flank, but increases over the next 20–60 min to become so severe that narcotic drugs may be needed for its control. The pain may remain in the flank or spread downward and anteriorly toward the ipsilateral loin, testis, or vulva. A stone in the portion of the ureter within the bladder wall causes frequency, urgency, and dysuria that may be confused with urinary tract infection. The vast majority of ureteral stones <0.5 cm in diameter will pass spontaneously.

It has been standard practice to diagnose acute renal colic by intravenous pyelography; however, helical CT scan without radiocontrast enhancement is now the preferred procedure. The advantages of CT include detection of uric acid stones in addition to the traditional radiopaque stones, no exposure to the risk of radiocontrast agents, and possible diagnosis of other causes of abdominal pain in a patient suspected of having renal colic from stones. Ultrasound is not as sensitive as CT in detecting renal or ureteral stones. Standard abdominal x-rays may be used to monitor patients for formation and growth of kidney stones, as they are less expensive and provide less radiation exposure than CT scans. Calcium, cystine, and struvite stones are all radiopaque on standard x-rays, whereas uric acid stones are radiolucent.

When the stone size is small, our medicine is likely to help in the passage of stone as well as in relieving the agonizing pain caused by the same.