Kidney stones (aka nephrolithiasis) are solid mineral deposits that form inside your kidneys. They can be found anywhere along the urinary tract -starting from the kidneys to the bladder-. Although kidney stones can cause excruciating pain, they usually don’t leave any long-term damage.
According to one study, nephrolithiasis affects 12% of the population in a lifetime; that’s 1.2 billion people in today’s population!
Moreover, kidney stones cause a budget toll of over $5 billion dollars annually; the calculation of this number is quite complicated, taking into consideration direct and indirect costs.
As you can see, kidney stones are a real public health issue. In this article, we’ll see the symptoms nephrolithiasis presents with, the most common types of stones, how to diagnose kidney stones, and the treatment options available for us.
This is the most common cause for patients to visit their doctor; it is caused by the distension of the renal capsule or the collecting ducts which are part of the renal system.
The severity of the pain varies greatly; it depends on how fast (the rate) the distension happens rather than its degree. So, the faster the obstruction occurs, the more excruciating the pain is.
The pain is usually located at the flanks (side or back under the ribs), and it radiates to the lower abdomen and the groin region.
Additionally, you may experience pain in an episodic fashion; in other words, you may have severe pain on one day, and on the next day, no pain is felt at all.
This is the typical description of the pain caused by nephrolithiasis. In fact, a good history and physical exam of the patient along with this description can be sufficient to make the diagnosis of a kidney stone.
It is the medical term used to describe pain when urinating.
Blood in urine:
This is caused by the irritation of the inner layer of the urethra; usually, it presents as pink, red, or brown urine.
In most cases, this shouldn’t be alarming and the amount of blood loss in the urine is too insignificant to cause any problems.
It is described as a sudden urge to urinate that can’t be stopped. This is caused by the abrupt contractions of the bladder muscles. The pathophysiology of this phenomenon isn’t fully understood, but it is thought to be caused by the irritation of the muscles by the kidney stone.
Pollakiuria is defined as excessive daytime urination frequency. The volume of urine in 24 hours does not necessarily exceed normal limits; it’s just that you pee too many times.
Unlike pollakiuria, polyuria can have a normal urinary frequency; however, the volume of urine in 24 hours will be superior to 2.5/3 liters.
Nausea and vomiting:
Along with the typical pain description and a good history, nausea and vomiting are part of the stereotypical presentation of nephrolithiasis.
Fever and chills:
This is typically not present when dealing with a kidney stone; however, when the stone blocks the flow of urine, bacteria will scroll up the urinary tract system and cause infection.
That’s right. One of the many functions of urine is to flush out bacteria.
When bacteria invade the bladder and cause an infection, it rarely presents with fever and chills; however, if the infection reaches the kidneys and causes what’s known as “pyelonephritis”, you can expect all the typical symptoms of an infection.
The diagnosis of kidney stones is mostly clinical; we can diagnose nephrolithiasis with a good, detailed history of the patient, and a focused clinical exam. Nonetheless, some other tests might be required to determine the etiology of the stone, as well as the potential and/or present complications.
Some of these tests may include:
- An electrolyte panel to measure the concentrations of calcium, phosphorus, uric acid, and other electrolytes.
- Blood Urea Nitrogen (BUN) and creatinine to evaluate renal (kidney) function.
- Urinalysis to check for crystals, pathogens, red blood cells, and white blood cells in the urine.
Other imaging tests might be ordered to take a closer look at the affected kidney. You can tell the level and site of obstruction, the damage caused by the stone, and in some cases, the nature of the stone.
The preferred imaging test for kidney stones is ultrasound. However, other tests such as MRIs, CT scans, and abdominal X-rays can be used as well.
Even though your doctor will try to figure out the nature of the stone that’s obstructing your urinary tract, oftentimes, a final conclusion can’t be reached.
What is sure; however, is that most kidney stones form because of a multitude of factors.
In general, kidney stones form when your urine is too concentrated and contains many crystal-forming substances such as calcium, phosphorus, and uric acid.
Usually, the water in your urine, as well as other substances, will prevent these chemicals from aggregating into a stone. Nevertheless, sometimes the body is just not capable to keep up and the stone will form and cause obstruction.
Hence, the importance of figuring out the type of kidney stone that formed. This way, we’ll know exactly what caused it and how to prevent it.
Types of kidney stones:
This is the most common form of kidney stone; usually, the calcium atoms aggregate with oxalate (a natural substance found in most foods) to form calcium oxalate.
Any condition that increases the concentration of calcium or oxalate can cause kidney stones.
High doses of vitamin D: taking high doses of vitamin D supplements will increase the absorption of calcium in your gut as well as decrease its excretion in the urine. This in return will cause hypercalcemia and as a result, a higher risk of stone formation.
Chronic renal failure: when your kidneys are not working anymore, electrolytes are not excreted properly; high electrolyte concentration in the blood can cause the aggregation of crystal-forming substances, especially in the absence of good hydration.
Small bowel resection: undergoing a surgery where a part of your bowel is resected will decrease the surface area of the gut. As a result, the absorption of substances such as calcium and oxalate is no longer strictly regulated.
A high concentration of oxalate in the blood will have the same effect as hypercalcemia -the formation of kidney stones-.
Crohn’s disease: similar to small bowel resection, Crohn’s disease will increase the absorption of oxalate from the gut, leading to a higher concentration of oxalate in the blood, and eventually kidney stones.
Metabolic disorders: multiple metabolic disorders are inherently known for their hypercalcemic effect, for example, hyperparathyroidism, diabetes, obesity, etc.
Calcium stones can also be formed from the association of calcium and phosphorus; although much less common, they are mostly seen in metabolic disorders such as acute tubular acidosis.
Uric acid stones:
As the name implies, uric acid stones are formed when you have too much uric acid in your blood. Any condition that increases the concentration of uric acid in the blood can potentially cause kidney stones. Here are a couple of situations where blood uric acid levels are high:
Diet: uric acid is the end product of protein metabolism; so, it would make sense that when you eat too many protein-rich foods, you have a higher chance of developing a uric acid kidney stone.
Dehydration: like any other stone type, dehydration is one of the leading factors for stone formation. If the substances that are responsible for kidney stones are not sufficiently diluted with water, the risk is higher.
Note that dehydration doesn’t have to be severe to cause nephrolithiasis; simply not getting the daily recommended amount of water can put you at a higher risk.
Gout: this is a medical condition where uric acid deposits inside articulations and causes severe pain, stiffness, and a decreased range of motion.
Gout occurs as a result of high levels of uric acid in the blood. The same uric acid can cause kidney stones.
This type of stone is also known as infection stone. It is formed after a urinary tract infection (UTI) caused by a urease-producing organism such as Proteus mirabilis or Klebsiella pneumoniae.
The enzyme urease will hydrolyze urea, leading to a spike in urine PH (above 8.5), where it becomes a favorable “milieu” for phosphorus atoms to aggregate together.
One particular characteristic of struvite stones is that they can grow very quickly and cause massive obstruction.
When the kidneys excrete excessive amounts of a substance called cystine which is formed by the association of two cysteine amino acids, kidney stones will form because of the aggregation of these substances.
This medical condition is referred to as cystinuria which is an inherited disorder; because of the genetic component of this disease, patients present with their first kidney stones at an early age compared to other stone types. In fact, even children can develop cystine stones.
When you first present to the ER with symptoms of nephrolithiasis, the doctor will primarily focus on symptom management. The reason is simple, the pain caused by kidney stones can be excruciating!
Your physician will ask you a few questions to get a better idea of your health history, he/she will then perform a physical exam, and the diagnosis of a kidney stone will be made.
Once a diagnosis has been established, you’ll get Intravenous (IV) fluids to dilute the stone and other stone-forming substances which in return will decrease the severity of your symptoms.
Your doctor will also prescribe Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) to manage the pain; however, in most cases, NSAIDs will not be enough to stop the pain, hence the need for narcotics administration, drugs such as morphine might be used.
If none of the above works, a special technique called shock wave therapy or lithotripsy might be performed by a trained urologist to break down the stone.
Lithotripsy uses a special ultrasound device to send shock waves at the location of the stone and break it down into smaller pieces that can be excreted via urine.
Depending on the size of the stone and the comorbidities of the patient, other surgical procedures may be indicated to remove the obstruction.
Another special surgical procedure performed to remove stones bigger than 2 cm (especially, cystine stones) is percutaneous nephrolithotomy (PCNL).
After anesthesia, your urologist will insert a small tube called a nephroscope through the skin into your kidney; a product will then be released at the site of the stone to break it down to be excreted in the urine.
This procedure is saved for complicated stones where other management plans can’t be of use.
Now that we’ve discussed the medical side of kidney stones, let’s finish this article by talking about some home remedies and diets that can help reduce the size or remove kidney stones altogether.
Hydration! Hydration! Hydration!
As we’ve mentioned earlier, drinking enough water is a cornerstone in the management of kidney stones; in fact, some patients reported getting rid of their stone simply by keeping themselves hydrated.
You can get a sense of your hydration status by looking at the color of your urine first thing in the morning; if it’s dark-yellow or brownish, it means you’re not drinking enough water.
Beverages with low PH will create an unfavorable environment for substance aggregation as well as bacterial infections.
You see, most stones form when the PH levels are high. This is also true for bacterial infections; most bacteria prefer an alkaline milieu to grow, so by decreasing the PH, you’ll stop any further substance aggregations and the complications associated with urinary tract infections.
Examples of acidic drinks include lemon juice, apple cider vinegar, and fruit juices in general.
Similar to drinks, some foods have been documented to promote renal (kidney) health and improve symptoms of kidney stones. Examples include:
- Vitamin B6
Due to the high prevalence of kidney stones as well as their severe morbidity, preventing stone formation is of the essence; eating a healthy diet as well as staying hydrated can save you from excruciating pain and some blunt surgical procedures.
However, this doesn’t mean that we can control kidney stones. In fact, sometimes they occur without any reasonable explanation and with no risk factors whatsoever.
In this case, it’s important to follow up with your primary care physician or your urologist to get the best possible care and plan your next step in the management of this condition.