الفهرس 
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Abstract
Crystals in the urine is known as crystalluria. It is frequently found during routine examination of the urine. Sometimes crystals are found in healthy people and other times they are indicators of organ dysfunction, the presence of urinary tract stone, or an infection in the urinary tract. They come in many different shapes and sizes.
Some forms of crystals appear in the urine of healthy individuals and most crystals, except for cystine are not considered cilinically significant. Freshy voided urine specimens are often devoid of crystals, but alkalization and refrigeration may promote crystals formation. While crystals are found in kidney stones, the presence of crystals in the urine doesn’t necessarily relate to stone formation. Cystine crystals, however are found only in patients with cystinuria, agentic impairment of tubular reabsorption of basic amino acids lysine, arginine, ornithine, and cystine).
There are many types of crystals like uric acid crystals, oxalate crystals and cystine crystals.
There was no significant difference in the incidence of each crystalluria type between males and females also there were no significant differences among age groups for both types of crystalluria. There were only two types of crystalluria are most predominant, those are uricacid and calcium oxalate and the incidence of uric acid crystalluria was significantly greater than oxalate in both genders and age groups.
There are many risk factors for crystals and stone formation like climate and geography. It is believed that individuals living in hot climates have an increased lifetime prevalence of stone disease secondary to dehydration. Also Urolithiasis incidence increases during summer and decreases during winter. It is generally attributed to the effect of seasonal variations in temperature on urinary volume.
Also BMI and weight are one of these risk factors, The prevalence and incident risk of stone disease were directly correlated with weight and body mass index in both sexes.
The risk of urolithiaisis is greater in individuals with a family history of stone disease. It is estimated to be more than 2.5 times greater in those individuals.
The most important risk factors is diet and water, low fluid intake and high dietary intake of animal protein, sodium, refined sugars, fructose and high fructose corn syrup, oxalate, grape fruit juice, apple juice, and cola drinks .
There are many causes for crystals and stone formation . the most important cause is metabolic causes like Hypercalciuria, Hyperoxaluria, Cystinuria, Hyperuricosuria and Hypocittaturia.
Also other causes include infection, structural abnormalities of the urinary tract and use of drugs like loop diuretics, laxatives, ciprofloxacin, sulfa medications and indinavir.
For diagnosis you must take full history from patient , examine him and then do investigations like metabolic evaluation and diagnostic imaging.
The metabolic evaluation for urolithiasis helps us to identify children those at increased risk for recurrent stone disease and also to diagnose specific treatable metabolic derangements.
Metabolic screening include Stone analysis, Blood test ( Bone Mineral Chemistry, that is serum calcium, phosphorus, alkaline phosphatase, albumin and parathyroid hormone- Renal tubular functions that is electrolytes such as sodium, potassium and chloride- Blood gas analysis) and Urine test ( Urine pH, Urine sediment for graveluria, pus cells, RBC, Urine culture and sensitivity test where indicated and 24-hour urine for calcium, phosphate, uric acid, sodium, citrate, oxalate and cystine (if cystinuria is suspected) .
Diagnostic Imaging of urolithiasis include Plain Radiography, Intravenous Urography, Ultrasound, Computed Tomography, Magnetic Resonance Imaging (MRI) and Retrograde Pyelography.
Dietary modifications may decrease stone formation in children dramatically. increasing fluid intake reduces the risk of stone formation. The volume of fluid intake should be adjusted to maintain urine volume greater than750mL/d in infants, greater than1000mL/d in children younger than 5 years, greater than 1500 mL/d in children between 5 and 10 years, and more than 2000 mL/d in children older than 10 years. Almost all beverages, including coffee, tea, wine, beer, and fruit juices, are acceptable. Water is the best beverage for stone formers. It is non-caloric, non-caffeinated, and contains insignificant amounts of solutes.
There is a common misconception that decreasing calcium intake will reduce the risk of calcium stone formation. In fact, studies have shown that low dietary calcium actually increases the risk of developing symptomatic kidney stones. Decreasing or limiting calcium intake is not recommended. Sufficient calcium intake is required for the growth and maintenance of the skeleton in children and adults.
Calcium intake for children should be according to the RDA for age. 500 mg/day for children one to three years - 800 mg/day for children four to eight years -1300 mg/day for children nine years and older. Dietary calcium is preferred to calcium supplementation because supplements may be associated with an increased risk of stone formation. The reason has not been fully elucidated but is thought to be secondary to timing of supplement intake or excessive total calcium . If patients require calcium supplements, calcium citrate should be utilized instead of calcium carbonate.
Oxalate restriction decreases the risk of recurrent stone formation in adults and the absence of any observation studies or clinical trials in children, restriction of dietary oxalate is not generally recommended for children.
Foods are classified according to the amount of oxalate in to Very high Oxalate foods which contain very large amounts of oxalate in the range of 50 – 520mg oxalate per serving size like Beetroot , Spinach and Sweet potatoes . All patients with calcium oxalate stones are advised to avoid these foods .
High Oxalate foods which contain large amounts of oxalate in the range of 10 – 50mg oxalate per serving like Olives , Potatoes and Blackberries. All patients with calcium oxalate stones are advised to avoid these foods .
Moderete Oxalate foods which contain moderate levels of oxalate in the range of 2 – 10mg per serving like Cabbage, Carrots and Egg plant . All patients with calcium oxalate stones are advised to limit these foods.
Low Oxalate foods which contain little or no oxalate from 0 – 2mg per serving like Apples, Apricots, Grapes, Broccoli and Watercress. All patients with calcium oxalate stones can enjoy these foods.
As there is a competition between sodium and calcium at nephrons and high sodium intake increases calcium levels in urine. The ideal daily intake of sodium varies according to age: 1.2 g for 4-8 years old children, 1.5 g for those aged 9-18 years. The corresponding upper limits are 1.9 g and 2.3 g, above which health risk may be attributable.
Potassium is mostly provided as dairy products, vegetables and fruits. Its optimal recommendations also vary according to age: 3.8 for 4-8 years old children and 4.5 g for those between 9 and 18 years. This is roughly equivalent to 3 units a day.
Also there are some studies in favor of decreased stone formation with low protein diets in adults, but protein limitation cannot be recommend to children who are still growing.
The Child take daily recommended intakes of protein. for Infant from 0-6 month take 9.1 gm per day, Infant from 7-12 month take 13.5 gm per day, child from 1-3 years take 13 gm per day, child from 4-8 years take 19 gm per day , male child from 9-13 years take 34 gm per day, male child from 14-18 years take 52 gm per day, female child from 9-13 years take 34gm per day and female child from 14-18 years 46 gm per day.