Humankind has been afflicted with urinary stones since 4000 BC. Kidney Stones Symptoms are basically is increasing urological disorder of human health and are one of the most common diseases of the urinary tract. It has also been associated with an increased risk of end-stage renal failure, chronic kidney disease, and cardiovascular diseases. According to a study conducted by the National Institute of Health (NIH), the United States affects almost 12% of the world population and its recurrence is of major concern in human health. The etiology of kidney stones is multifactorial and before we can discuss it in further details it’s important to know about its mechanisms.
What are Kidney stones?
Kidney stones are small particles that are found along the inner lining of our kidney as a result of precipitation of certain particles from the urine. They are mostly calcium oxalate stones though occasionally they might also be uric acid stones, struvite stones, and cystinuria stones. This process of formation of stones is called nephrolithiasis (nephros- kidney, lithos- stone) and the stones themselves are called renal calculi (calculi- pebble).
How many types of kidney stones are there?
These are the most common type of kidney stones. They occur either due to the presence of calcium and oxalate or calcium and phosphate (rare).
Uric Acid Stones-
They occur when our urine is too acidic (the pH level below 5.5) on a regular basis. They occur in people having less fluid content in their bodies. Uric acid can result either from genetic problems resulting in faulty processing of the uric acid in the body leading to the deposition of uric acid in the body or due to consuming a diet high on purines (pork, poultry, and eggs). The uric acid can settle down by itself and form a stone or can form it in combination with calcium.
They occur as a result of any infection in the urinary tract. Struvite is actually a mineral that’s produced by bacteria in our urinary tract by breaking down the waste product urea into ammonia. These types of stones are produced by any bacterial infection that hydrolyzes urea into ammonia thus raising the urine pH to alkaline values. Thus our urine needs to be alkaline for Struvite to be produced and any type of urinary tract infection causes our urine to turn alkaline thus increasing the chances of these types of stones.
These stones are formed due to a rare autosomal recessive disorder called cystinuria. This disorder causes the leakage of amino acid, Cystine into the urine. When there is too much of Cystine secretion, they crystallize and solidify to form Cystine stones. Most people with this type of stone have recurring stones.
How are kidney stones formed?
Our kidneys filter our blood, secrete waste products and allow their reabsorption into the bloodstream thus maintaining the electrolyte and fluid balance of our bodies. Once the blood has been filtered and sent into the body through the efferent arteriole (arteriole carrying filtered blood into the body), the filtrate travels along the nephron (structural and functional unit of kidneys) passing through the PCT(Proximal Convoluted Tubule)to the Loop of Henle and finally through to the DCT(Distal Convoluted Tubule) to the collecting duct.
When the filtrate travels through the nephron tubule the electrolytes present in them start accumulating in the tubule and form crystals. These crystals are formed in everybody, even in people who never have kidney stones symptoms. These crystals are actually urinary stones which might eventually pass out with urine if they are small ones but if they don’t pass out they will gradually start accumulating in the kidney and will solidify into kidney stones.
Why do these crystals solidify into kidney stones?
Our urine naturally consists of substances that promote the growth of crystals. Their substances come into our urine from our bloodstream as our kidneys are bestowed with the responsibility of determining the constituents of our urine (It determines whether and how much of the urinary constituents will be reabsorbed). These substances are Calcium, Oxalate, and Uric Acid.
Along with stone-promoting substances, our urine also consists of stone-inhibiting substances. These substances are collectively called as urinary macromolecules. They include citrate, magnesium, pyrophosphate, and proteins derived from normal metabolism. These inhibitors aid in the elimination of crystals before they solidify into stones.
In order for the tiny crystals to solidify into stones, the urine must be supersaturated due to any one of the following reasons or a combination of these-
- Low urine volume.
- Abnormally high concentration of stone promoters.
- Abnormally low concentration of stone inhibitors.
Under normal circumstances, the balance between the urinary stone promoters and urinary stone inhibitors helps to eliminate the tiny crystals formed in our kidney. If there is any kind of imbalance in these constituents either due to genetics, lifestyle, or other factors the crystals form into kidney stones.
What are the major Kidney Stones Symptoms contributing to the growth of kidney stones?
Low Urine Volume
When urine volume is less, it becomes concentrated. Concentrated urine indicates fewer amounts of fluids to keep the salts dissolved. A low volume of urine is often a major factor in Kidney Stones Symptoms contributing to the formation of kidney stones.
The food we put into our mouth directly affects the formation of kidney stones. One of the major Kidney Stones Symptoms’ is the presence of high levels of calcium in our urine.
Having excessive levels of salt in our diet contributes to Kidney Stones Symptoms because when the urine eliminates the excessive salt through urine it eliminates Calcium along with it too. Thus there is an excessive amount of calcium in the urine which leads to the formation of crystals finally solidifying into stones. Thus reducing our sodium intake can decrease the level of calcium present in our urine thus reducing the chances of kidney stones.
Some bowel conditions like diarrhea or surgery in our intestinal region can be another Kidney Stones Symptoms leading to the formation of kidney stones.
If we have diarrhea there is an excessive fluid loss from our body leading to the decrease in the urine volume increasing the chances of formation of kidney stones.
Obesity plays a very significant role in the formation of kidney stones. Obesity is related to insulin resistance and compensatory hyperinsulinemia (excessive levels of insulin in the blood as compared to glucose). Hyperinsulinemia increases the secretion of calcium in urine thus contributing to the formation of calcium stones. It may also lead to excessive secretion of uric acid and oxalate thus increasing the chances of calcium oxalate kidney stones. A new study from John Hopkins University concluded that obesity increased the incidence of kidney stones by almost 2%.
Certain medical conditions like Distal Renal Tubular Acidosis (the kidneys don’t remove the acids from the blood in the urine) which leads to an acid build-up in our body increases the chances of Calcium Phosphate kidney stones.
Another condition involving the abnormal growth of one or more parathyroid glands (that control Calcium metabolism) can possibly contribute to the formation of kidney stones.
People with Type 2 diabetes are at increased risk of having kidney stones, particularly uric acid stones. A study conducted by researchers at the Mayo Clinic over 3,500 participants during a 20-year span showed subjects with diabetes had developed 40% more uric acid kidney stones than those without diabetes.
Individuals having a family history of kidney stones are at more risk of developing Kidney Stones Symptoms than people who don’t have it. In a research conducted in a cohort of 37,999 male participants by the National Institute of Health (NIH), the United States in the year 1986 the relation between family history and risk of kidney stones was studied. It was found out a family history of kidney stones was much common in men with a personal history of stones at baseline than in those without a history of stones. During the 8-year follow-up, 795 incident cases of stones were documented. However, a family history of kidney stones substantially increases the risk of stone formation. In addition, the data mentioned suggest that dietary calcium restriction may increase the risk of stone formation, even among individuals with a family history of kidney stones.
What are the possible Kidney Stones Symptoms?
Kidney stone symptoms may be asymptomatic till it passes into your ureter. At that point you might experience the following symptoms:-
- Severe pain in the back, belly, or side which radiates to the lower abdomen and groin.
- Pain during urination.
- Blood in the urine (hematuria).
- Nausea and vomiting.
- Urinating in very small amounts.
- Frequent urination.
- Excessive sweating.
What are your treatment options?
Medical Expulsive Therapy (MET)
According to evidence, stones less than 10 mm in diameter can pass through the urinary tract spontaneously. In this case, an alpha-blocker medication such as tamsulosin (Flomax) or calcium channel blocker medication such as nifedipine (Procardia) is administered. Both of these are classes of drugs that have been shown to relax the spasming ureter thus speeding up the passage of kidney stones.
Extracorporeal Shock Wave Lithotripsy (SWL)
A shock wave lithotripsy machine delivers shock waves through the skin to the stone in the kidney. The success rate of the treatment depends on the stone size and position-
- Stones less than 10 mm in size can be successfully treated.
- For stones of 10-20 mm size, factors like stone composition and stone location should be considered.
- Stones larger than 20 mm are usually not successfully treated with this.
- Stones in the lower third part of the kidney are problematic as they can’t be cleared out from the kidney as easily as the upper and the middle part as the fragments don’t pass out through the kidney easily due to gravity.
Percutaneous Nephrolithotomy (PCNL)
In this process, the surgeon can gain access to our kidney stones through a small incisor at the lower back. A power such as a laser is used to break down the stones into fragments which are then flushed out from the kidney through an external tube or internal stent. This type of treatment is carried out for larger kidney stones of 2cm or more, complex stones, or lower pole renal stones larger than 1cm.
During this process, a tube is placed through the urethra and bladder all the way through the ureter and finally into the kidney. It employs very flexible instruments (like a flexible telescope) through which the surgeon can have a clear view inside the urethra. Then a power source is used to crush the stones into pieces using the ureteroscope under direct visualization.
How to prevent kidney stones?
Though the reason behind the formation of kidney stones hasn’t been uncovered fully, one of the single biggest contributors to its formation was found out to be Our Diet
The DASH DIET
The DASH DIET stands for Dietary Approaches to Stop Hypertension. It was a diet created by experts from the National Institutes of Health (NIH), Unites States. It is known for its ability to decrease hypertension (high blood pressure). This diet consists of foods that are low in saturated fat, cholesterol and sodium and rich in protein and fibers.
According to a research conducted on a large-scale basis at the Brigham and Women’s hospital, it found out that people following the DASH diet had 40-45% fewer chances of developing kidney stones. The reports were similar irrespective of the age, gender, BMI, or diabetes of the participants. The participants following this diet also had a high urine volume mainly because of the high water content of this diet. According to researchers this decrease in kidney stones is also due to the high fruit and vegetable content of this diet which increases the amount of stone-inhibiting substance citrate thus decreasing the chances of formation of kidney stones. Additionally, this diet also contains low sodium and animal protein intake further contributing to the decrease of chances of kidney stones.
DASH Diet Guidelines
Daily calorie intake – 2,000 calories a day.
About 6 to 8 servings of grains are recommended every day. These include cereals, rice, and bread. Whole grains (brown rice, whole-wheat pasta, and whole-grain bread)must be included instead of refined ones (white rice, regular pasta, white bread) as they contain more fiber and nutrients. Butter, cheese, or cream must be avoided to retain their full nutritional value.
About 4 to 5 servings of vegetables are recommended every day. This includes green leafy vegetables like broccoli, sweet potatoes, and other vegetables containing fiber, vitamins, and essential minerals (potassium and magnesium).
About 4 to 5 servings of fruits are recommended every day. Fruits are naturally high on fiber, vitamins, and essential minerals. Make them a part of your daily regimen. Leave on the edible peel offs of the fruits as they contain healthy nutrients and fiber too.
About 2-3 servings of dairy are recommended every day. Low-fat or fat-free options must be preferred.
Animal Protein (Lean meat, poultry, and fish)
At least 6 one-ounce servings or fewer a day is recommended. Too much intake of animal protein like red meat, poultry, and eggs increases the level of uric acid and contributes to kidney stones. A diet high on protein also reduces the level of citrate in our urine which helps to prevent stone formation in the kidney. Meat can be a very rich source of protein, Vitamin B, iron, and zinc. Choose lean varieties of animal protein. Cutting back on the meat portion will also allow for more consumption of vegetables.
Nut, seeds, and legumes
About 4 to 5 servings of nuts, legumes, and seeds are recommended each week. They might include almonds, kidney beans, lentils, peas, and other foods of this family as they are very good sources of magnesium, potassium, and protein. They also consist of fiber and phytochemicals. Servings should, however, be restricted to small ones per week as they add calories to our diet. Nuts contain healthy types of fats – monosaturated fat and omega-3 fatty acids. So including them in your diet in moderation (it is rich in calories) will do wonders for your body in the long run. Soybean-based products like tofu and tempeh can also be used as a good alternative to meat.
Fats and Oils
About 2 to 3 servings of fats and oils are every day. Fats help our body to absorb essential vitamins and also aids in our body’s immunity though more of it increases the risk of heart disease, diabetes, and obesity. This diet ensures a healthy balance by limiting the total fat intake to less than 30% of our daily calories from mainly consuming healthier monosaturated fats.
About 5 servings of sweets are recommended every day. The focus should be on consuming fat-free or low-fat sweets like hard candy or low-fat cookies.
Decrease in calcium levels in our body can lead to an increase in oxalate levels which further leads to the formation of kidney stones. So, a diet containing food rich in calcium will help to fight against this but be cautious enough to avoid calcium supplements as studies have linked them with kidney stones. Ideally, men aged 50 and above should consume 1,000 mg of calcium per day along with 800 to 1000 IU (International Units) of Vitamin D to help the body absorb the calcium.
A high sodium diet can lead to kidney stones as it increases the amount of calcium in our urine beyond the permissible limit. So, a diet low in sodium is recommended to curb the formation of kidney stones. Current guidelines of The DASH Diet suggests limiting our daily total intake to 2,300 mg for a standard diet and about 1,500 mg of sodium in low sodium diet
Eat food with low oxalate levels
People with high amounts of oxalate in urine are recommended to eat food with low oxalate. Eating foods rich in Calcium regulates the oxalate amount of our body but even if eating calcium doesn’t lower the oxalate level in our body then food containing low oxalate is recommended. For stone prevention, a reasonable goal will be consuming less than 100 mg of oxalate every day.
Drinking plenty of fluids is recommended for kidney stone prevention. An increase in the fluid content of our body dilutes the volume of the stone-forming substances in urine decreasing the chances of formation of crystals. However, all fluids don’t have this same effect. E.g. Water, beverages like tea, coffee, beer, wine, etc. have been associated with a lower risk of kidney stones whereas consuming a lot of soda may contribute to kidney stones too.