Let's talk about Kidney Stones

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Let's talk about Kidney Stones

Infamous for the reports of extreme and sometimes disabling pain they can cause, sometimes even considered more aggressive than birth pains or burns, kidney stones are a very common pathology of the urinary tract. The actual name of the condition is Renal Lithiasis.

The kidneys are part of our blood filtration system, retaining water, salts and minerals that are expelled in the form of urine. When there is a large amount of minerals and a small amount of water to dissolve them, these salts and minerals become saturated and crystallize, forming small aggregates that can clog the urinary system. These stones, as they are commonly known, are called Renal Calculi.

Although it is in the kidneys where these stones are mostly formed and lodged, they are not limited to these organs, and may sometimes move and become lodged in the ureters and bladder. This displacement through the ureter, which is a very narrow channel that allows the passage of urine from the kidney to the bladder, sometimes does not happen and the stone becomes blocked, which can lead to episodes of intense pain.

Kidney stones vary greatly in size and grow over time, if not properly treated, ranging from a few millimeters to more than 10 cm, filling the entire kidney. The biochemical composition of the stones can also vary, thus influencing the type of treatment and response required for their removal.

According to the Prostate Institute, “it is estimated that this pathology affects between 2 to 3% of the world population, predominantly Caucasian men” and that “the probability of having an episode of renal colic, in patients with stones, up to 45 years of age, is around 9%.

Main Symptoms

Symptoms of kidney stones usually only start after they begin to move out of the kidneys. Until that moment, they usually go unnoticed, as long as the stone is not large.

Symptoms of kidney stones typically include:

  • fever above 38º C (usually an indicator of infection);
  • nausea and vomiting;
  • increased urge to urinate;
  • pain or burning sensation while urinating;
  • bloody urine;
  • sudden severe pain in the lower back that may radiate to the abdomen and/or groin — Renal Colic.

Main Causes

The exact causes for the appearance and increase of kidney stones are difficult to identify. Due to their gradual growth nature and the variety of possible factors involved, it is sometimes only possible to identify certain risk factors associated with kidney stones, such as:

  • low daily fluid intake;
  • diet rich in protein, salt and sugar;
  • low fiber diet;
  • obesity;
  • high retention of urine for extended periods;
  • genetic predisposition and/or family history of kidney stones;
  • sedentary lifestyle;
  • chronic urinary tract infection;
  • hyperparathyroidism (causes an increase in the level of calcium in the blood);
  • other kidney pathologies;
  • extended use of certain medications and/or supplements (such as aspirin, anti-acids and diuretics);

Renal Colic

Renal colic is the name given to the least desirable of all the symptoms of kidney stones. This happens when there is effectively an obstruction (total or partial) of the passage of urine through the ureters.

When obstructed, the stone (or stones), which due to its mineral composition has a very spiked and sharp surface, causes an acute and very intense pain in the lumbar region, so strong that it can result in nausea and vomiting. It is considered one of the most difficult pains to bear, even surpassing the levels of pain in childbirth or even skin burns, according to reports. The pain can also radiate to other surrounding areas, such as the abdomen and groin, making it impossible for the patient to have any comfortable position.


Kidney stones are diagnosed by a urologist or general practitioner, initially by analyzing the symptoms revealed by the patient, the most common being a renal colic, which implies that the stone is already of considerable size and the patient is in the emergency room.

It is imperative for the effective treatment of kidney stones to accurately determine the exact location of the stone and its size. Therefore, after analyzing the symptoms and clinical history of the patient, the doctor performs a clinical examination and confirms the diagnosis through a few complementary diagnostic tests. These exams generally include:

  • urine analysis (to try to determine the composition of the stone)
  • imaging tests, such as ultrasounds of the kidneys and bladder, or ultrasound and x-ray (to accurately pinpoint the location and size of the stone)


The treatment of Renal Lithiasis varies depending on the size, location and composition of the kidney stones:

  • Dimension

Kidney stones can vary greatly in size and the same patient can have several stones all of different sizes at the same time:

      • < 5 mm – known as sand or microlithiasis;
      • > 5 mm – known as staghorn calculi;
  • Composition

The composition of kidney stones may differ in their biochemical composition, which may directly affect the type of treatment required:

      • Calcium – this mineral is present in most of the stones found (between 75% and 80%) and unfortunately they cannot be dissolved with medication;
      • Uric acid – less common than calcium (between 5% to 10%), uric acid stones can sometimes be dissolved with medication;
      • Struvite – more rare, these are stones produced by bacteria that cause chronic urinary infection;
      • Cystine – rare and extremely hard, they are the result of a hereditary genetic disease;
      • Medication – sometimes, depending on the type of medication taken, this can have the side effect of kidney stone formation.
  • Location

Kidney stones can become lodged in different organs of the urinary system, starting with the kidneys, each with specific considerations regarding the process for their removal:

      • kidneys
      • ureters
      • bladder
      • urethra

In the vast majority of cases (between 80% and 85%), kidney stones are of reduced size and pain levels are therefore tolerable, thus their elimination is achieved by waiting for them to be eliminated naturally through the urethra. Sometimes, certain drugs are applied in order to help both with the pain felt by the patient and to facilitate the elimination of the stone, by trying to dissolve them. The patient can also, as indicated by their doctor, opt for the tea popularly known as stone break tea to help the dissolution of their stones.

In these mild cases, the patient is asked to stay at home and rest, to drink plenty of fluids and to respect the guidelines advised by their doctor regarding the use of painkillers or antispasmodics, and the medications that assist on the dissolving of the stones. The patient should also be careful with their diet, avoiding foods with high sodium and protein content.

In cases where the stones are larger or are found deep inside the kidneys, and therefore cannot be expelled through the urethra without great discomfort and pain for the patient, it is necessary to resort to surgical methods to remove them. Among these processes we can find the following:

  • Shock-Wave Lithotripsy (SWL) – is a non-invasive method in which shock waves that penetrate the skin and tissue are used to break up the stones. Once fragmented, they should already have sufficient reduced dimensions to be expelled through the urine;
  • Uretorescopy (URS) – is the most used procedure and involves the insertion of an endoscope into the urethra, which can reach the interior of the kidney, and through surgical instruments the calculus is removed;
  • Percutaneous nephrolithotomy (PCNL) – when the stones are too large to be removed through the channels of the urinary system, we have to resort to a kidney puncture surgery, starting from the skin in the lumbar area, and removing the stone with instruments surgical procedures, namely a nephroscope.

Both treatment methods (dissolution and direct removal) are quite effective, with high success rates. However, since this is a disease mostly caused by bad habits, if these are not changed, it is likely that the clinical picture will repeat.


One of the most well-known risk factors in the formation of kidney stones is diet. Playing an active role in prevention will include:

  • increase fluid intake – in order to reduce the chance of crystallization of salts and minerals;
  • reduce salt consumption – especially in processed and canned foods;
  • reduce consumption of foods that raise uric acid levels – such as red meat, seafood and beer



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