Types of Kidney Stones

Kidney stones come in different shapes and sizes, depending on what type of minerals were crystallized. The most common types of kidney stones are:

Calcium oxalate

This is the most common kind of kidney stone. It usually forms when there’s an excess of oxalate in the urine. These can happen when you are chronically dehydrated, consume a diet high in protein, oxalate, or salt, and with certain medical conditions such as bowel disease.

Uric acid stones

Uric acid is produced as a byproduct of protein metabolism. Uric acid requires alkaline urine to stay dissolved. If urine is too acidic, uric acid crystals form and deposit in the kidneys. People who inherit problems in processing uric acid (eg gout in the family), are overweight, have Type 2 diabetes, or eat high animal protein diets are at greater risk of this type of stone.

Struvite stones

These stones are made from magnesium ammonium phosphate deposits.  They are formed when urine is highly alkaline due to the activities of some bacteria in chronic urinary tract infections. Struvite stones aren’t common, but they are large, have branches, and grow fast when they form.

Cystine stones

These stones form in the presence of cystinuria. In this rare inherited condition, the kidneys cannot reabsorb cystine from urine. Cystine crystallizes into stones.

Symptoms of Kidney Stones

Small kidney stones are often asymptomatic and may pass out on their own without hassle. The larger ones, however, often get stuck in the urinary tract (most often the ureters) or cause irritation as they are moving through. This can be accompanied by the following symptoms:

• Renal Colic – sharp pain on your back, lower abdomen and sides
• Bloody urine
• Nausea and vomiting
• Frequent need to urinate
• Pain while urinating
• Fever – this indicates a possibly infected stone and requires urgent surgery

Causes of Kidney Stones

Kidney stones form as a result of different factors and are usually not limited to a single cause.  However, because kidney stones are formed from the crystallization of excess minerals and hard salts in the urine, anything that leads to an excess of these minerals vs the amount of water in your urine can increase your risk of developing kidney stones.

Some common causes of kidney stones are:

Low Volume of Urine

One of the most common reasons you may form kidney stones is not producing enough urine in a day. Your kidneys are responsible for filtering waste out of your body through urine. Many of this waste is dissolved in the urine and passed out. When you produce too little urine volume,  there isn’t enough water to dissolve the minerals which then crystallize to form stones.

Dehydration

is the primary reason your body may not be producing enough urine. You are dehydrated if your body loses more fluid than you take in. If you are not taking enough liquid,  you may become susceptible to forming kidney stones. On average, a healthy person with no underlying conditions should produce up to 2.5 litres of urine per day. To produce this amount, you would need to consume about 3 litres of fluid, which can come from sources other than water. A person who has never formed stones can aim to drink 2L of water a day, while a stone-former should try to drink closer to 3L a day. Other ways you can get dehydrated include:

• Losing a lot of sweat when you exercise over a long period
• An illness that causes frequent vomiting and diarrhea
• Health conditions such as diabetes and alcoholism

Medical Conditions

Living with certain medical conditions like hyperparathyroidism can increase your risk of forming kidney stones. This is because the parathyroid glands are responsible for calcium metabolism in your body. When there is an abnormality, it can lead to high levels of calcium in your blood and urine, which may lead to the formation of kidney stones.

Distal renal tubular acidosis, a condition where there is an acid build-up in the body, can also increase your risk of kidney stones. Other medical conditions that can predispose a person to kidney stones include cystinuria and hyperoxaluria.

Genetics

You may be more likely to get kidney stones if your family members have a history of kidney stones.

Diet

Your diet can increase your risk of developing kidney stones. Food rich in animal protein such as fish and beef can raise your body’s acid levels, making it easier for stones to form in your kidneys. When you eat food rich in oxalate, you can also increase your risk of forming calcium oxalate kidney stones. Other causes of kidney stones include Crohn’s disease, polycystic kidney disease, gastric bypass surgery, obesity, and certain medications such as calcium-based antacids.

How to Prevent Kidney Stones

Stay Hydrated

Hydration is the best way to prevent the formation of kidney stones. It is advisable to drink at least 2-3 litres of fluid every day.

Diet

You can switch up your diet to reduce animal protein while adding more fruits and vegetables. Lowering your calcium intake may not have a significant effect on lowering your risk of forming kidney stones. Instead, your doctor may recommend reducing your sodium (salt)  intake as an excess may encourage the formation of calcium stones.

How to Treat Kidney Stones

After your doctor makes a kidney stone diagnosis through necessary tests such as urine tests,  blood tests, x-rays and CT scans, they would recommend treatment options based on the type,  size, and location of stones you have. If the stones are small, your doctor may ask you to drink a lot of water and wait until the stone passes by itself. They may also recommend medications like pain relievers, anti-nausea medication, and Tamsulosin to relax your ureters to allow easier passing of the stone.

Surgery

For larger stones, possible surgical procedures include :

Lithotripsy

This procedure involves using shock waves to break kidney stones into small pieces after which these fragments will pass out of your body in your urine. This procedure is usually carried out under general anesthesia.

Ureteroscopy

In this procedure, your urologist will insert a long tube-shaped instrument into your urethra then up to your bladder and finally your ureter, search for the stone, and either remove or break it then remove the pieces. No cuts are made, instead, the surgeon uses the natural channels in your body to travel with the narrow flexible scope. This procedure is usually used when stones cause a blockage.

Percutaneous nephrolithotomy

Rarely, this surgical procedure may be required to remove a  large kidney stone. An instrument is passed through a small cut in your back directly to the kidney to remove the stone. This happens when the stone is too large to pass and causes obstruction, pain, or threatens to harm the kidney function.

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