Urinary Stones Urolithiasis Kidney stones nephrolithiasis

1. Urinary StonesUrolithiasisKidney stones nephrolithiasis Dr. Ahmed EL tahir

2. Kidney stones Also known as nephrolithiasis, urolithiasis or renal calculi. Solid concretions ( crystal aggregations) of dissolved minerals in urine found inside the kidneys or ureters. They vary in size from as small as a grain of sand to as large as a grapefruit

3. Kidney stones (calculi) are hardened mineral deposits that form in the kidney. They originate as microscopic particles and develop into stones over time. The medical term for this condition is nephrolithiasis, or renal stone disease.

5. A vast majority of stones will contain elements of calcium within them and therefore are easily seen on x-ray having the same density as bone. Depending on the size, number, and the location of the stone(s) as well as it's composition guides initial and then further management can be implemented.

7. Kidney stones occur in 1 in 20 people at some time in their life. Urolithiasis is rare in children. When present, it is often associated with specific metabolic disorders or anatomic abnormalities. For precipitation of crystals in urine to occur, the urine must be "supersaturated" for the precipitating crystal.

8. Stone formation secondary to infection and/or obstruction related to a congenital malformation of the urinary tract often present before the age of 5. Cystinuria, idiopathic calcium oxalate urolithiasis and primary hyperparathyroidism more often begin around puberty or in the mid-teens.

9. Stone Formation Kidney stones form when there is a high level of mineral (s) ; i.e. calcium (hypercalciuria), oxalate (hyperoxaluria), or uric acid (hyperuricosuria) in the urine; a lack of citrate in the urine; or insufficient water in the kidneys to dissolve waste products. Urine normally contains chemicals—citrate, magnesium, pyrophosphate—that prevent the formation of crystals.

10. Low levels of these inhibitors can contribute to the formation of kidney stones. Citrate is thought to be the most important The chemical composition of stones depends on the chemical imbalance in the urine. The four most common types of stones are comprised of calcium, uric acid, struvite, and cystine.

11. Calcium Stones: Approximately 85% of stones are composed predominantly of calcium compounds. The most common cause of calcium stone production is excess calcium in the urine (hypercalciuria). In hypercalciuria, excess calcium builds up in the kidneys and urine, where it combines with other waste products to form stones. Low levels of citrate, high levels of oxalate and uric acid, and inadequate urinary volume may also cause calcium stone formation.

12. Calcium stones are composed of oxalate (calcium oxalate) or phosphate (calcium phosphate). Calcium phosphate stones typically occur in patients with metabolic or hormonal disorders such as hyperparathyroidism and renal tubular acidosis. These stones come in 2 different types - monohydrate and dihydrate. Calcium oxalate dihydrate stones usually break easily with lithotripsy. Monohydrate stones are among the most difficult stones to fragment.

13. Cause of hypercalciuria. Increased intestinal absorption of calcium (absorptive hypercalciuria), excessive hormone levels (hyperparathyroidism), and renal calcium leak (kidney defect that causes excessive calcium to enter the urine) Prolonged inactivity also increases urinary calcium and may cause stones. Renal tubular acidosis (inherited condition in which the kidneys are unable to excrete acid) significantly reduces urinary citrate and total acid levels and can lead to stone formation.

14. Calcium oxalate monohydrates

16. Uric Acid Stones Digestion produces uric acid. If the acid level in the urine is high or too much acid is excreted, the uric acid may not dissolve and uric acid stones may form. They are not visible on X-rays. Patients with gout often develop these stones. Uric acid stones form in acidic urine and often dissolve when the urine is alkalinized.

17. Cont. Genetics may play a role in the development of uric acid stones, which are more common in men. Approximately 10% of patients with kidney stone disease develop this type of stone.

18. Uric acid

19. Struvite Stones Also called an infection stone, develops when a urinary tract infection (e.g., bladder infection) affects the chemical balance of the urine. Bacteria in the urinary tract release chemicals that neutralize acid in the urine, which enables bacteria to grow more quickly and promotes struvite stone development. They are capable of splitting urea into ammonia, decreasing the acidity of the urine and resulting in favorable conditions for the formation of struvite stones.

20. Cont. Organisms which alkalinize the urine can cause struvite stones to form. Struvite stones are more common in women. The stones usually develop as jagged structures called "staghorns" and can grow to be quite large.

21. Struvite

22. Cystine Stones Cystine is an amino acid. Some people inherit a rare, congenital condition that results in large amounts of cystine in the urine. This condition (called cystinuria) causes cystine stones that are difficult to treat and requires life-long therapy.

23. Cystine

24. Family history, Age of onset, Fluid intake pattern, Diet, medications, History of infections. Certain stone formation has a genetic predisposition Some an autosomal recessive pattern, including cystinuria and primary hyperoxaluria, Some have an autosomal dominant pattern such as renal tubular acidosis (RTA) or the syndrome of idiopathic calcium oxalate urolithiasis.

25. Causes and Risk Factors A low level of citrate is a risk factor for hypocitraturia. Congenital kidney defect that may increase urinary calcium loss and stone formation (medullary sponge kidney) Excessive parathyroid hormone, which causes calcium loss (hyperparathyroidism) Gout (caused by excessive uric acid in the blood) High blood pressure ( hypertension) Inflammation of the colon that causes chronic diarrhea, dehydration, and chemical imbalances (colitis) Sodium (hypernatremia)

26. Inherited condition in which the kidneys are unable to excrete acid (renal tubular acidosis) Painful joint inflammation (arthritis) Urinary tract infectious (affect kidney function) Diet plays an important role in the development of kidney stones. A diet high in sodium, fats, meat, and sugar, and low in fiber, vegetable protein, and unrefined carbohydrates increases the risk for renal stone disease.

27. High doses of vitamin C (i.e., more than 500 mg per day) can result in high levels of oxalate in the urine (hyperoxaluria) and increase the risk for kidney stones. Oxalate is found in berries, vegetables (e.g., green beans, beets, spinach, squash, tomatoes), nuts, chocolate, and tea. Stone formers should limit their intake of cranberries, which contain a moderate amount of oxalate.