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Urinary System Lithiasis

Urinary system lithiasis is defined as the stones’ formation anywhere in the urinary tract.Urinary System Lithiasis

Thus, depending on stones’ localization, there is ‘nephrolithiasis’ – i.e. in cases that stones are identified in the kidneys – ‘ureter lithiasis’ when stones are detected in the ureter, and ‘gritty bladder end’ when they are located at the urethra.

Urinary system lithiasis is one of the most common diseases of the urinary system and occurs more often in men. Normally, urine contain substances and salts which are in the form of the solution and thus discharged without any problem. Sometimes, though, under certain conditions, these salts form crystals which are joined together and create the stones.
Factors favoring the formation of urinary stones are:

1. Excessive secretion of insoluble substances in urine

In cases that there is an increased urinary calcium excretion (hypercalciuria), the kidneys can not eliminate all the amount of dissolved calcium. This leads to crystal formation, who provide the springboard for stone formation.

In cases that there is an increased urinary calcium excretion (hypercalciuria), the kidneys can not eliminate all the amount of dissolved calcium. This leads to crystal formation, who provide the springboard for stone formation.
Such cases include:

-> Prolonged immobilization (after accidents or fractures)
-> Primary hyperparathyroidism
-> Bone diseases such as Paget, metastatic tumors and multiple myeloma
-> Hypervitaminosis D
-> Increased consumption of increased hardness water

2. Increased concentration of cystine in the urine (cystinuria)

3. Increased concentration of xanthine and uric acid in urine

4. Increased density of salts and organic compounds in urine or decreased water intake even after high water loss (fever, excessive sweating)

5. Changes in urine pH

6. Stone nucleation

7. Urinary tract infection by microbes that break down urea and create appropriate conditions of sedimentation and magnesium / ammonium phosphate stone formation (inflammatory stones).

8. Gene factors.

 

Types of Urinary Stones

Depending on their chemical composition, stones are discern into the following categories:

-> Mixed (oxalate and phosphate Ca) [35% -40%] – stones are soft or hard of a yellow or brown color.

-> Calcium oxalate stones [30% -35%] – single stones of small size and spiny

-> Magnesium ammonium phosphate (inflammatory) [10% -15%] – stones are usually yellow in color, soft and may reach a large size (coral).

-> Uric acid stones [8% -10%] – usually in large numbers, of small size and not distinguishable in radiography.

-> Cystine stones [2% -3%] – usually in large numbers, homogeneous and smooth usually appear in both kidneys.

The clinical presentation of urinary stones’ varies from asymptomatic until symptoms like renal colic, hematuria, fever, frequent urination, dysuria and hydronephrosis appear.