TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (2023)

Types of kidney stones

TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (1)

The crystals form stones and their names indicate the types of kidney stones. These are the names of the crystals that form the stones: CAOX, Calcium Oxalate. CAP, calcium phosphate; UA, uric acid; cystine; struvite

The slices in my pie chart show the relative abundance of stone types in the large population of stone-forming patients. Calcium oxalate stones predominate by a wide margin in our clinic and in all others that I know of.

Names matter because the whole science of stone preventionfocus on stone crystals. Each kidney stone crystal creates its own disease and requires specific treatment. This is why we name stones by their crystal names and why when stones are analyzed, results are reported using these exact names.

A bold graphic and quite large, the projected image does what it sets out to do, bringing out key events like, in a circus, large and small animals roam the ring as an introduction. Come over. I will show all the common stones, like at a fashion show or a circus show. You can watch as they pass by and remember or wonder which ones could have been yours.

Is here.

What type do you have?

You might think your doctors know which stones you've formed, but don't count on it. People move, doctors move, health records are not "all electronic".That stone report from 4 years ago could be in a dusty file, your new doctors don't know it exists. Even worse, it could be hidden in a dresser drawer and you forget about it and put it there. Perhaps even worse, the stones could remain in that drawer, never analyzed. Find the stones, find the missing reports, ask your doctors for analysis. They can help you more if they know your stone analysis.

When they don't know, doctors can still make prevention efforts, but with less focus and possibly less effect than when guided by knowledge of crystals. So always seek treatment. If a stone appears in the road, do everything possible to analyze it.

Why should you care to know all this?

Because you will be doing a lot of your own healing for many years to come.

As stones tend to recur, prevention requires treatment over long periods of time. These treatments work withchanges urine chemistry in a direction that minimizes the risk of crystal formation. This change in urine chemistry requires control of fluid intake, lifestyle and diet, and sometimes additional use of medications.

Just as the sailor who follows a chosen course against the random, disorienting, and confusing sea and wind maintains a steady course in proportion to the skill that comes from knowing the ship's course, patients who aspire to maintain a certain kind of condition in their urine despite the demands and temptations of the world that they do, I think, depending on the skills that come from knowing how their work, life and food affect their bodies and how these crystals that they want so much to prevent.

In other words, knowledge is power.

Why is this article so long?

I wanted to put the five main types of kidney stones. It makes a great story. But you're probably only interested in reading about your own type.

I should mention here, to avoid too much confusion, that stones often contain mixtures of crystals.

The pie chart refers to the most common crystals in a stone, which is why the stone is often given its name. Most of the time, the crystal's minor components aren't critical, but sometimes, to take it a step further, they are. Even a trace of struvite or cystine, for example, can be of great diagnostic importance.

calcium stones

Calcium Oxalate Crystals

In the big circle at the top of this article page, the calcium oxalate stone, which is the most common, takes up the most space.TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (2)

Calcium oxalate crystal forms when calcium combines withoxalateacid. A dead-end waste excreted by the kidneys, oxalic acid (left) contains two carbon atoms (the big black spheres), four oxygen atoms, and two hydrogen atoms (silver).TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (3)

In acidic urine, positively charged hydrogens give up their negatively charged oxygens. As a result, the oxalate molecule carries two negative charges. In the figure on the right, a negatively charged oxygen attracts a hydrogen from a nearby water molecule (H – O-H), while another attracts a positively charged calcium atom.

You can imagine how another oxalate ion (named for a charged molecule in water) could attract the same calcium, or another calcium atom would attract oxygen from the bottom of the oxalate molecule, so that the chain would stretch out and form a crystal.You can see more about this in a video I made.In general, although my more experienced colleagues may resent such simplification, calcium atoms and oxalate molecules are held together by the attraction of their opposite charges.

Calcium oxalate kidney stones come in two varieties, calcium oxalate monohydrate and calcium oxalate dihydrate. The former are harder and therefore more resistant to fragmentation by lithotripsy. Likewise, the former occur more frequently when there are high levels of oxalate in the urine.

Calcium oxalate stone formers

Systemic Diseases

Sometimes this kidney stone results from a systemic cause such as bowel disease, primary hyperparathyroidism, or primary hyperoxaluria. Only doctors can determine that a known illness, such as bowel disease, is the cause of the stones. Only doctors can discover the underlying primary hyperparathyroidism as the cause of the stones. Patients cannot do much for themselves except to provide as complete a medical record as possible.


Most of the time, this kidney stone simply results from the interaction between heredity, diet and aspects of daily life.they call these patients idiopathic calcium oxalate stone formers, fDo grego Idios idios "de si" e pathos pathos "Suffering".

Although doctors are discovering links between everyday life and stone production, andchoose those changes that can prevent new stones,Patients themselves must create and maintain these changes. I think patients can do this depending on how well they understand what is needed and why. When changes in daily life are not enough, doctors add drugs, so that patients remain active healers of their own illness.

Stones usually form on kidney surfaces

About one million units of nephrons make up a normal adult kidney. The calcium oxalate type of kidney stone does not develop in the tubules of the nephrons, but "outside" them, on the surfaces of the renal pelvis where the final urine collects and drains through the ureter into the bladder.Here is a video showing how they can be formed.

calcium phosphate crystals

Phosphate ions and urinary pH

Calcium phosphate stone crystals form when calcium atoms combine with phosphoric acid instead of oxalic acid and produce a calcium phosphate kidney stone.

TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (4)Phosphoric acid is simply a phosphorus atom (shown as 'P' in the diagram on the left) with 4 oxygen atoms attached to it. An oxygen atom has two lines for its bond with phosphorus. this oxygen cannot provide any charge with which to bond the calcium atoms to form a crystal. The other three have common links shown by a solid dashed line and an arrow. Those two arrows just mean that the oxygens are above and below the plane of the paper, so if you were to build the molecule out of sticks and balls, it would have a 3D shape.

One of the three negatively charged oxygens never has hydrogen in urine, but only in highly acidic solutions. A second charged oxygen is always occupied by a hydrogen atom in urine.

This makes the third oxygen, occupied variably by a hydrogen in the urine, a buffer.

In normal medium acid urine (pH about 6), most of the dissociated oxygens have their hydrogens leaving the only negatively charged phosphate ion. It is not enough to make a crystal.

When urine is abnormally alkaline (pH greater than 6.3 or 6.5), free oxygen is charged so that the ion has two negative charges that can combine with calcium to form crystals. For this reason, calcium phosphate kidney stones tend to occur in people who produce more alkaline urine than those who produce calcium oxalate kidney stones.

Brushita vs. hidroxiapatita

Like calcium oxalate, calcium phosphate crystals start out simply as pairs of double negative phosphate ions with double positive calcium atoms. This unique crystal is called brushite. Brushite, which is a mixture of equal parts calcium and phosphate ions, can be turned into hydroxyapatite (HA), which has a more unbalanced ratio of calcium to phosphate. Hydroxyapatite crystals harden bones.

Because it is less soluble than brushite, hydroxyapatiteI cannibalize brushite.Heorganic molecules in urine modify tyour process

Calcium phosphate stone formers

systemic diseases

Primary hyperparathyroidism and renal tubular acidosis increase mean urine alkalinity (higher urinary pH) and promote calcium phosphate kidney stones. Many rare genetic diseases do the same.


idiopathicCalcium phosphate stone formers share a common set of characteristics. Perhaps because urine contains much more phosphate than oxalate, it forms larger and more frequent stones than the idiopathic calcium oxalate stone-formers.Stones usually originate as glass plugs at the terminal ends of the renal tubules..More crystals are deposited on the open end of the plug to form the final stone.Glass plugs destroy the cells that line the tubules and cause localized scarring.

uric acid stones

uric acid crystals

Structure and paid sites

A product of DNA and RNA breakdown, uric acid forms crystals in abnormally acidic (low pH) urine. Obese and diabetic people, people with gout or kidney disease often produce abnormally acidic urine. I know how urine becomes acidic, but save that for another part of the site.

Uric acid,the molecule of interest here (shown on the right), has two joined rings of carbon atoms (located at the corners where the lines meet), withTYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (5)intermediate atoms of nitrogen (N), oxygen (O) and hydrogen (H).

This molecule has only two charged sites, the nitrogen atoms at the bottom of the rings. In urine with a pH of around 6, nitrogen is devoid of hydrogen and therefore carries a single negative charge. In more alkaline solutions, both nitrogens are dehydrogenated, but urine normally does not reach such alkalinity (pH>8).

When the urine pH is low (<5.5) and the two nitrogens have their hydrogens, the molecule lacks charged sites, so water can no longer build on the molecule. Crystallize. It simply leaves the water like water droplets that form from high, misty clouds in the late afternoon and fall from the air like warm spring showers.

relationship with water

agua each of the molecules is a single oxygen atom (big ball) bonded to two hydrogen atoms (small balls), as in this Wikipedia image. The hydrogen side has a positive charge, the naked oxygen side negative. Thus, water molecules stick together,TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (6)positive on negative surfaces, to form the clear, seemingly continuous liquid that we drink, swim in, and hold umbrellas to protect ourselves when it rains. They are connected with a load at an angle, indicated by the number "1" to form a three-dimensional macrame.

To be "in solution" is to have some charge to which water molecules can bind by attraction. Calcium atoms are positive and surrounded by a shell of water molecules in front of them with their negative surfaces bare. Oxalic and phosphoric acids have negative charges and are surrounded by water molecules that point at them with their positive or hydrogen sides.

Uric acid at neutral pH has the only negatively charged nitrogen that water can absorb. But when the pH drops, and even nitrogen has no additional charge to bind water, how can the molecule get among the water molecules? I can't. Molecules accumulate into solid crystals and come out of solution.

Uric acid stone formers

The stones can be orange-red, large and numerous.

Stones may be red or orange because uric acid crystals absorb the breakdown products of hemoglobin, which are orange-red pigments in urine. Sometimes uric acid crystals pass in the urine as a reddish-orange pebble.

Uric acid does not need to bond with another atom or molecule to form a crystal, just as calcium must bond with oxalate or phosphate ions to form crystals of calcium oxalate or calcium phosphate. When the pH is low enough to extinguish its charge, uric acid can crystallize very quickly, within seconds, passing as orange gravel in the urine. If retained, these crystals can quickly turn into large stones. Since there is much more uric acid in the urine than oxalic acid, uric acid stones can grow large and quickly. Some fill the entire collecting system of the kidney.

Urine pH controls stone formation

But since the whole process depends almost entirely on the acidity of the urine, uric acid stones are easily treated.Just a moderate amount of supplemental alkali will make almost any patient's urine alkaline.enough to remove hydrogen atoms from the critically charged nitrogen. Water can bind there so uric acid stays in solution. Because it is so simple, the treatment definitely prevents stones. Relapse should never happen.

Mixed stones require special care

Unfortunately, however, the stones often contain uric acid mixed with calcium oxalate. In this case, it is necessary to identify the cause of the calcium oxalate stones, as well as make the urine alkaline enough to prevent uric acid stones from forming. Calcium phosphate crystals are rarely mixed with uric acid because very alkaline urine is needed to remove the phosphate hydrogen atoms, so it has two negative charges and can bind calcium atoms effectively. At that higher pH, uric acid will take the place of charge and remain in solution.

struvite stones

urea and the planet

The kidneys cannot produce struvite. Bacteria do this. Not all bacteria either. You need bacteria that normally thrive in soil, and they do for compelling and age-old reasons. These bacteria produce the kidney stone called struvite.Heinrich Christian Gottfried von Struve(of)(1772-1851).

Animals deposit urea (left) all over the planet when they urinate. Plants cannot use it.

TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (7)Like oxygen, nitrogen is essential for life but dangerous. It is an integral part of proteins, DNA and RNA. As these molecules break down and rebuild, some of their nitrogen escapes and can form poisonous compounds unless trapped in safe waste. Of these, the mainurea,contains 2 nitrogen atoms bonded to a single carbon atom ("C" in the left image).

Uric acid contains 4 nitrogen atoms (see figure). Birds and reptiles excrete most of their nitrogen in the form of uric acid. mammals like us excrete nitrogen mainly as urea.

As the world's animals urinate in the soil, its urea carries nitrogen to plant roots, but plants cannot use it. They cannot release the nitrogens from the carbon atom that contains them. Those soil bacteria that produce struvite crystals have an enzyme, called urease, that can release nitrogen for plants to use as a nitrogen supply.

So soil urease bacteria maintain the soil nitrogen cycle.

struvite crystals

As they release nitrogen from its carbon in urea, the nitrogen takes on a proton and produces ammonia (NH3). Ammonia is a strong alkali and takes another proton.

As they do so, the active bacteria are surrounded by spheres of highly alkaline liquid enriched with ammonium ions (NH4) which carries a positive charge. Soil magnesium (an atom with two positive charges) and phosphate stripped of all its protons (an ion with three negative charges) spontaneously form their triple salt: three negative charges phosphate, two positive charges magnesium, one positive NH4).

The crystals anchor bacteria and help create a porous, nitrogen-rich core good for plant growth.

struvite kidney stone

because they start

Because urine is full of urea, soil bacteria that enter the urinary tract can break it down into ammonia and create struvite from the magnesium and phosphate that urine always contains.

You may be wondering how soil bacteria get into the urinary tract.

Because we eat them, with foods that aren't cooked, and they become part of the gut bacteria population early on. In and around us, they find their way into the urinary system, especially in women whose smaller urethra facilitates entry. No matter how cleverly used, any instrument placed in the bladder can carry our soil bacteria with it.

oh what are they doing

Because they live among molds and fungi, soil bacteria easily develop resistance to antibiotics, so antibiotics given for a UTI tend to kill susceptible bacteria and select for those that can resist them.

Soil bacteria can produce de novo struvite stones or contaminate calcium stones to produce a mixed stone. In any case, struvite stones are contaminated by their very nature. They can get huge. Its bacteria can damage the kidneys and even get into the bloodstream and cause sepsis.

Treatment is a combination of careful surgery and a choice of antibiotics after surgery to kill any remaining bacteria. If the stones are a mixture of struvite and calcium crystals, further calcium stones should be avoided.

cystine stones

Hereditary kidney anomaly

TYPES OF KIDNEY CALCULATIONS | Kidney stone evaluation and treatment program (8)Yellow lemon with sugar coating, formed only in people whoan inherited kidney disease called cystinuria.

Although the kidneys are functioning well, they allow abnormal amounts of four amino acids to enter the urine. Three doesn't matter, we know. The fourth produces crystals and cystine-type kidney stones.


cystine(left) is formed by coupling two identical amino acids, called cysteine, through their sulfur atoms ("S" in the drawing).

Each cysteine ​​contains two carbon atoms, not seen except at the corners, linked together (shown by the single long line connecting the two corners) as in oxalic acid.

A carbon atom has 2 oxygens attached to it. the other has a nitrogen (making it the nitrogen-containing amino acid), a hydrogen atom, and a sulfur atom. For phosphates, the solid, dashed arrows simply mean that the hydrogens and sulfurs are above and below the plane of the page, and a rod model will have a 3D shape.

cystine crystals

Cysteine ​​itself is highly soluble because the sulfur atom has a significant negative charge.

But the big, long cystine molecule has very little charge because the sulfurs are bonded together. Thus, like uric acid, cystine loses its affinity for water molecules and simply comes out of solution as crystals. Also, like uric acid, the process is fast.

cystine stones

Because people with cystinuria lose large amounts of cystine in their urine, stones develop easily and quickly.

It is possible for stones to form in the urine itself. But cystine crystals can clog the ends of the kidney tubules, as can calcium phosphate crystals, causing cell damage.

As cystinuria is a hereditary disease, stones can appear in childhood.

Effective treatment always requires large amounts of fluid to dilute the urine. The few effective drugs look like cysteine. Its sulfur groups combine with cysteine ​​to form a "mixed disulfide" that is more soluble than cystine. But its side effects can limit its use.

rare stones

From time to time we encounter patients who manufacture unusual crystals and require very special care.

Uric acid, for example, can form strange crystals like sodium or ammoniacal uric acid, especially in people with intestinal diseases and chronic diarrhea.

Antiviral drugs can crystallize in the urine and form stones that are recognized for what they are only by analyzing the stones.

Very rare metabolic disorders can produce molecules that crystallize in the urine, e.g. 2-8 dihydroxyadenine.

While it may take some time for the correct answer to emerge, stone analysis will put clinicians on the right track for these special cases.

End of a very long post.

This is my parade.

The common animals and the rarer animals have been ignored, and you've seen the main ones, big and small.

The only point is what it was in the beginning. Each type of kidney stone has its own forms, and treatment requires knowing which one you have.

Likewise, whatever it is, it's good to know as much as you can about it. For the long-term prevention of stones is difficult to achieve and, ultimately, what matters most is the patience and persistence of the patients themselves.

If you don't know what stones you made, find out.

Locate the old references and assemble them.

Keep copies and send everything to your attending physicians.

Learn what you can about the stones you make so you can do what's best for you for years of prevention.

Dr. Fred Coe

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