Kidney Stone

Kidney stones, also known as renal calculi or nephrolithiasis, are solid, small masses that are formed when salts or minerals, which occur normally in urine, crystallize within the kidney. Usually, these crystallized kidney stones are very tiny and go unnoticed, passing out harmlessly from the body. However, when they start building up they become larger, and can create problems.

In case the kidney stone does become large enough, it can start moving out of the kidney, progressing down via the ureters, which tubes through which urine flows from the kidney to the bladder. In case the stone gets lodged in the ureter, it can lead to infection, which in turn can result in permanent damage to the kidney.

Why do Kidney Stones Form?

In case the levels of uric acid, also referred to as hyperuricosuria, oxalate, known as hyperoxaluria, calcium, known as hypercalciuria, sodium, known as hypernatremia, or cystine, known as cystinuria, which is because of a genetic disorder, are high in urine; or there is a deficiency of citrate in urine; or there is not enough water to dissolve the waste products in the kidneys, it can result in the formation of kidney stones.

A certain amount of water has to be maintained in the body by the kidneys in order to remove the waste products. In case there is dehydration, it results in the accumulation of high levels of matter such as uric acid, oxalate, calcium and so on, which do not fully dissolve, which then crystallize, slowly building up to form kidney stones.

Normally, urine has certain chemicals such as pyrophosphate, magnesium, and citrate, which help in preventing the crystallization that results in kidney stones. Therefore, there are higher chances of kidney stones forming when there are low amounts of these inhibitors. Amongst these, citrate is considered to be the most vital, and leads to condition known as hypocitraturia.

High concentrations of oxalate in urine due to vitamin C being taken in high doses, above 500 mg per day, which causes hyperoxaluria, also increases the chances of kidney stones forming. Foods like nuts, vegetables such as tomatoes, squash, spinach, beets, green beans, tea and chocolate are high in oxalates, while there is a moderate amount in cranberries.

Diet also is an important factor in the formation of kidney stones, particularly in people who are susceptible to it. For example, if a person’s diet comprises of high levels of sugar, sodium, meat and fats, and the fiber content is low, there are higher chances of renal calculi forming.

The medical conditions given below can also lead to the formation of kidney stones:

• Infections of the urinary tract, which affects the functioning of the kidneys.
• Disorders of the intestinal tract that results in chronic diarrhea, which leads to dehydration, and therefore low levels of citrate, e.g. Crohn’s disease.
• Painful inflammation of the joints, such as in arthritis.
• Genetic disorder wherein the kidneys lose their ability to excrete acid, such as renal tubular acidosis.
• Inflammatory condition of the colon which results in chronic diarrhea, leading to dehydration, which causes chemical imbalances, e.g. colitis.
• Hypertension, wherein the blood pressure remains abnormally high.
• Gout, caused by defects in the metabolism of uric acid, resulting in high levels of uric acid and its salts in the blood.
• High levels of parathyroid hormone, which results in the loss of calcium, or hyperparathyroidism.
• Congenital defect of the kidneys that can lead to an increase in the loss of calcium via the urine and the formation of kidney stones, such as in medullary sponge kidney.

What are the Symptoms or Signs of Kidney Stones

Small sized kidney stones that are smooth can be present in the kidney or even be passed without causing any pain, which are known as ‘silent’ stones. However, when stones travel into the ureter and get stuck there, they result in the spasm of the urinary system, resulting in pain. The size of the stone does not determine the pain, which usually is felt radiating from the lower back to the groin or the side. Usually, stones measuring around 8 mm in diameter or more need medical attention, whereas those that are about 4 mm or less in size are usually passed out spontaneously.

Some of the other signs of kidney stones are:

• Abdominal tenderness, particularly in the area of the kidneys.
• Hematuria, or blood present in the urine.
• Painful urination, or a burning or stinging sensation.
• Nausea and even vomiting.
• An increase in the frequency of passing urine.