The formation of stones in the kidneys or urinary tract is a fairly common disorder. The stones are formed from the chemicals usually found in the urine such as uric acid, phosphorus, calcium and oxalic acid. They may vary in consistency from grit, sand and gravel-like obstructions to the size of bird’s eggs.
Stones may form and grow because the concentration of a particular substance in the urine exceeds its solubility. This disorder occurs more frequently in middle age, with men being afflicted more often than women.
The kidneys are two bean-shaped organs, lying below the waist of either side of the spinal column on the back wall of the abdomen. They are soft, reddish brown in colour, and, on an average, measures 10 cm. in length,’6 cm. in width and is 2.5 cm. thick at its centre. They are each composed of approximately one million similar functional units called nepthrons.
Kidneys are the filtering plant for purifying the blood, removing water and salts from it which are passed into the bladder as urine. The kidneys are connected to the urinary bladder by two tubes called ureters in which the urine is stored. From here the urine is periodically emptied through another tube known as the urethra.
Symptoms
Kidney stones usually cause sevece pain in their attempt to pass down the ureter on their way to the bladder. The pain is first felt in the side and thereafter in the groin and thighs. Other symptoms of kidney stones are a frequent desire to urinate, painful urination, scanty urination, nausea, vomiting, sweating, chills and shock. The patient may also pass blood with the urine. Sometimes large stones may remain in the kidneys without causing any trouble and these are known as ‘silent’ stones.
Causes
The formation of stones in the kidneys is the result of defects in the general metabolism. They usually occur when the urine becomes highly concentrated due to heavy perspiration or insufficient intake of fluids. They are aggravated by a sedentary life style. The other causes are wrong diet, excess intake of acid-forming foods, white flour and sugar products, meat, tea, coffee, condiments and spices, rich foods and overeating. Lack of vitamin A and an excessive intake of vitamin D may also lead to formation of stones.
Types of Stones
Chemically, urinary stone.s are of two categories, namely, primary stones and secondary stones. Primary stones are ordinarily not due to infection and are formed in acidic, urine. They usually result from alcoholism, sedentary life, constipation and excessive intake of nitrogenous or purine-rich foods. Secondary stones are due to local infection and are formed in alkaline urine.
Most kidney stones are composed either of calcium oxalate or phosphate, the latter being most common in the presence of infection. About ninety per cent of all stones contain clacium as the chief constituent. More than half of these are mixtures of calcium, ammonium and magnesium, phosphates and carbonates, while the remainder contain oxalate. Uric acid and cystine stones represent about four per cent and one per cent, respectively, of the total incidence of stones.