Kidney Stones are also known as Renal Calculus. They are hard substances, made up of a combination of some minerals and chemicals such as calcium, phosphate, urate, oxalate, etc.
Stones occur in the kidneys, ureters, bladder, or urethra. Some kidney stones pass out of the body on their own but some stones which got stuck and cause kidney problems required surgery.
Structure & Function of the Kidney
Our body consists of a pair of brown, bean-like organs called Kidneys. Kidneys are located just below the rib cage and behind the peritoneum (a membrane lining the abdominal cavity that covers and protects most of the organs in the abdomen). The position of the left kidney is slightly higher than the right. This is because the liver (the second largest organ of the human body) is also present on the right side. A kidney consists of an outer shell called the Renal Cortex, a central part called the Renal Medulla, and an inner part called the Renal Pelvic. The kidney filters the blood from the renal artery, from where the blood moves into the functional units of the kidney called the nephrons. There are millions of nephrons in one kidney. The nephrons start from the renal cortex and dip into the pyramids present in the renal medulla. The nephrons filter the blood and remove the waste products from the blood. The waste (urine) is then collected by the renal calyces which are present in the renal pelvis from where the urine passes into the ureter. After completing the process and removing the waste the blood is reabsorbed by the renal vein. The area from where the renal artery, renal vein, and ureter come out of the kidney is called the hilum.
How Kidney Stones are Formed?
When the urine is formed if the concentration of waste products such as calcium, oxalate, and phosphate is high then these substances start to join together and form crystals. There are two reasons for crystal formation. Number one is Supersaturation (it occurs when a solute is above its concentration of solubility in the solvent) in the urine due to which the chemicals and minerals accumulate. The second reason is that inhibitors are insufficient. Inhibitors are the substances that avoid the minerals from joining together. For example, citrate is an inhibitor. It means that the urine of a healthy person is undersaturated and there are enough inhibitors present to prevent crystal formation. Other factors due to which the stones formed include drinking very little water, family history, and some medical conditions.
Which size of Kidney Stones require Surgery?
The kidney stones differ in size. For example, they are as small as a grain or as large as a golf ball. Most of the time the small stones that are five millimeters or less may pass out of the body without surgery and the stones that are more than five millimeters in size may require surgery. But it is not necessary because in some cases large stones of 1cm in size or more tend to pass out of the body without any surgery and in other cases, small stones which are two or three millimeters in size need surgical treatments because of causing infections or damages to the kidney.
Types of Kidney Stones
1. Calcium Oxalate Stones
The most common types of kidney stones are calcium oxalate stones. When there is a high concentration of oxalate and calcium in the urine, both of these elements combine to form kidney stones. Other causes are not drinking enough water, intake of food high in oxalate, hyperparathyroidism, dent disease (genetic kidney disease), obesity, etc. Food that could cause calcium oxalate stones are peanuts, nuts, rhubarb, spinach, etc.
2. Uric Acid Stone
Uric acid is a waste product present in the blood that is formed after the breakdown of purine substances. When there is a high amount of uric acid in the blood it starts to form uric acid stones. Food that could cause uric acid stones is beef, chicken, fish, shellfish, etc.
3. Struvite Stones
When the urine is alkaline (basic) means that the PH is more than 7 or when there is an infection in the urinary tract, there are chances of getting struvite stones (infected stones). The PH is the measurement that shows how acidic or basic the fluid is. The logarithmic scale ranges from 0 to 14. So, if the PH of fluid is less than 7 then it is acidic. If the PH is 7 then it is neutral, if more than 7 then basic. The urine becomes more alkaline when the bacterial infection breaks down the urea into ammonium increasing the PH of urine. The bacteria that cause the breakdown of urea are Staphylococcus, Mycoplasma, Klebsiella, Pseudomonas, etc. The struvite stones are also known as Ammonium magnesium phosphate stones.
Symptoms of Kidney Stones
Uric acid is a waste product present in the blood that is formed after the breakdown of purine substances. When there is a high amount of uric acid in the blood it starts to form uric acid stones. Food that could cause uric acid stones is beef, chicken, fish, shellfish, etc.
Diagnosis & Treatment
Diagnosis of kidney stones includes X-rays, CT scans, urine tests, ultrasounds, etc. Treatments for kidney stones include shockwave lithotripsy, ureteroscopy, percutaneous lithotripsy, and some medications.