Food & HealthScience & Technology

Kidney stones

Kidney stones are the most common pathology of the urinary tract. Vietnam is located in a hot and humid tropical climate, the body loses a lot of water, so it has long been considered an endemic area for stones. About 10-14% of Vietnamese people have stones in their kidneys. In the US, a survey shows that 7-10% of people have had a kidney stone once in their life without even knowing it. The worldwide prevalence is around 3% of the population and varies from country to country.

What are kidney stones?

Kidney stones are a common urolithiasis in middle-aged men. The age of the disease is usually from 30 to 55 years old (1). Men have a more complex urinary tract structure, so stones are often difficult to eliminate on their own as in women.

Urinary stones are solid particles formed by the natural crystallization of inorganic crystals in urine. They can cause pain, nausea and vomiting, haematuria, and can cause fever and chills because of secondary infections. Most of them begin to form in the kidneys, move along the path of the urinary system and are excreted, so many people are familiar with them as kidney stones.

When the urinary system begins to deposit and crystallize stones, small crystals and stones often go through the urinary tract and are excreted. At a certain place in the urinary tract, crystals or stones get stuck, continue to settle and crystallize to form larger stones.

Here, the size of the stone grows larger, which can obstruct the flow of urine, leading to urine stagnation, dilatation in the upper part of the blockage. It is at this location that many complications will occur such as infection, crystallization and formation of different types of stones… gradually destroying the kidney structure.

Based on the position of the stone on the urinary system, people can also name or classify stones:

  • Kidney stones are urinary stones located in the kidney, including calyces and pyelonephritis.
  • Ureteral stones: caused by stones moving from the renal pelvis to the ureters and causing obstruction of the urinary tract.
  • Bladder stones: 80% are caused by stones from the kidneys, ureters falling down or due to blockage in the bladder neck, urethra
  • Urethral stone: when the stone follows the urine stream from the bladder to the urethra, it gets stuck here.

Types of kidney stones

Stones in the urinary system are often classified according to their chemical composition (2), including:

  • Calcium stones are the most common stones, accounting for 80-90%, including Calcium Oxalate and Calcium Phosphate stones. Calcium Oxalate accounts for a high percentage in tropical countries like Vietnam. This stone is very hard and opaque, has a rough appearance, yellow or brown color
  • Common phosphate stones are Magnesium Ammonium Phosphate, also known as infectious stones, usually caused by long-term urinary tract infections, especially by proteus bacteria. The stones are yellow and slightly friable. This type of stone is usually very large and can fill the renal calyces causing coral stones.

 

  • Uric acid stones form due to increased purine metabolism in the body. The causes can increase purine metabolism such as using a lot of foods containing a lot of purine substances (such as pork intestines, beef intestines, dried fish meat, mushrooms …), or patients with gout, or stones formed by decomposition tumours during chemotherapy.
  • Cystine stones are formed due to errors in the reabsorption of cystine in the renal tubules. This stone is relatively rare in Vietnam. Cystine stones are non-contrast stones with a smooth surface. Signs of kidney stones

Symptoms of kidney stones are purely caused by complications of the stone with the urinary system, not by the stone itself.

(3) Renal colic pain

The most obvious manifestation of kidney stones is that they cause severe pain, so much so that people call it “renal storm pain” or “renal colic”.

Stone causes pain in the lumbar fossa on one side, spreading anteriorly and downward. It is the onset, which comes on very suddenly, after strenuous activity. Then the intensity of the pain became stronger. Patients often writhe in pain, struggling to find a position to relieve pain but can’t.

When experiencing this symptom, the patient needs to immediately go to the medical agency, the hospital so that the doctor can take measures to reduce the pain caused by kidney stones, absolutely do not arbitrarily do it at home.

 

It is possible to distinguish two cases of kidney stone pain

  • Pain due to kidney stones due to obstruction of the renal pelvis and calyx: The pain occurs in the lumbar fossa, below the 12th rib, pain radiates forward towards the navel and the pelvic fossa.
  • The pain of ureteral stones: originates from the fossa of the lumbar region and spreads downward along the ureter, to the pelvic fossa of the genitals, the inner surface of the thigh.

Symptoms accompanying kidney stone pain are nausea, vomiting, abdominal distension due to intestinal paralysis. Patients may have fever, chills if there is a combined urinary tract infection. When the doctor examines, the flank pain can be seen. The points of pressure on the ureter are also painful, and an enlarged kidney may be seen.

There was no relationship between the size or number of stones and the occurrence and intensity of renal colic. In some cases, such as silent stones, the patient has absolutely no pain symptoms, or the pain is not obvious such as low back pain on one or both sides…

Blood in urine

The case of stones with rough surface, coral spines … when rubbing against the urinary tract, it causes blood in urine. Normally, kidney stones do not cause this phenomenon. However, due to the patient’s activity, or vigorous exercise, it causes blood in the urine.

Stuck, blocked urinary tract

The urinary tract is like a water pipe, when a stone appears, it causes blockage and blockage. Including urinary retention, kidney obstruction, hydro nephrosis. Because these signs are similar to many other illnesses, it is important to see a qualified doctor to analyse the cause and make a diagnosis.

Causes of kidney stones

There are many causes of kidney stones, starting from crystallization, crystal deposition in the urinary system. According to experts, urinary stones can form because urine contains too many chemicals, typically calcium, uric acid, cystine… 85% of stones form from calcium deposition.

The specific causes indicated are:

  • Not drinking enough water: The body does not have enough water for the kidneys to excrete, the urine is too thick.
  • High salt diet: This is a common cause in Vietnamese people, Vietnamese taste is quite salty. Salt and fish sauce are familiar spices every day… Eating a lot of salt (NaCl), the body has to increase the excretion of Na+, increase Ca++ in the renal tubules… Therefore, calcium stones are easy to form.
  • High protein diet: Protein in food increases urine pH, increases calcium excretion and reduces the absorption of Citrate.
  • Loading calcium and vitamin C supplements in the wrong way: We add too many micronutrients, leading to an excess of them in the body. As for Vitamin C, when converted into oxalate radicals. And Ca++ ions will compete and inhibit the absorption of other ions such as Ze ++, Fe ++, etc. When the kidneys have too much substances, they will be overloaded, of course, there will be an increased risk of stone formation here.
  • Consequences of gastrointestinal diseases such as stomach ulcers, diarrhoea… can also form calcium Oxalate stones. Diarrhoea causes dehydration, loss of Na + K + ions, …. decreased urine output; Oxalate concentration in the urine increases, etc., thereby easily forming stones.
  • Genetic factors: The disease can also run-in families. The risk of disease in members of the same bloodline, is higher than normal.
  • In people who are congenital or acquired, have urinary tract malformations, causing urinary tract obstruction for example due to prostatic hypertrophy, diverticulum in the bladder, prostate fibroids…. Some patients are traumatized and cannot move for a long time. Urinary tract obstruction causes urine, which accumulates for a long time, to form kidney stones.
  • Urinary tract infections. Infiltrating bacteria, causing persistent urinary tract inflammation, creating pus, depositing long-term secretions is also the cause of kidney stones.
  • Obesity: According to some studies, the risk of obesity will be higher than that of normal people.

Are kidney stones dangerous?

When a stone becomes lodged inside the urinary tract, it affects the urinary tract in three stages:

Resistance phase

At this stage, the upper part of the urinary tract with stones will increase contraction to push the stone out. Both the ureters and the upper renal pelvis are not dilated. There is a sudden increase in renal calyx pressure causing renal colic. Clinically at this stage, the patient often presents with typical renal storm pain.

Dilation phase

This stage is a consequence of the resistance phase. After about 3 months without pushing the stone out, the ureter, renal pelvis and calyx above the obstruction will be dilated. Decreased ureteral motility

Complication’s stage

The stone does not move for a long time because it is attached to the mucosa. The ureter is thickened and may become narrowed. During this stage, kidney function will gradually decline. Kidneys are waterlogged. And if there is an infection, there will be pus stasis.

The presence of stones in the urinary tract is a predisposing factor for re-infection. For a long time, it will cause chronic pyelonephritis and lead to chronic kidney failure.

Tests – Diagnose kidney stones

In order to diagnose kidney stone disease accurately and provide an effective treatment plan, the patient will have to perform many laboratory tests (4).

 That is Supersonic:

When nephrolithiasis is suspected, the first diagnostic method indicated is ultrasonography, because it is quite effective, simple, and less effective. When ultrasound, the doctor can detect stones, and at the same time can predict the degree of fluid retention of the kidneys, ureters and the thin thickness of the renal tissue.

Some cases of stones, without obvious complications or symptoms, were discovered incidentally during an ultrasound examination for some other reason or during routine general examinations.

Urine test

This is a mandatory test in the diagnosis of kidney stones. Because from the results of this test can conclude a lot about the condition of the disease – stages and complications, especially Urinary tract infections.

Check the sediment

Oxalate, phosphate, and calcium crystals… These are the components of kidney stones. It can be concluded that the type of stone is existing and forming in the urinary system.

Urine pH

Bacteria will decompose Urea into Ammonia, so when the pH is > 6.5, it can be concluded that it is a urinary tract infection.

Proteinuria

If there is a lot of protein in the urine, the doctor will have to diagnose more glomerular diseases because if it is only a urinary tract infection, there is very little protein in the urine. Find cells and germs

Urine test found many red and white blood cells. If a kidney stone is suspected to have an infectious complication, when centrifuging, microscopy and Gram staining can show bacteria in the urine.

ASP – Abdominal X-ray unprepared

Most of the urinary system stones in Vietnam are contrast-enhanced stones, so X-ray is very valuable in diagnosis. This measure helps the doctor locate the contrast stone, tell the size, number and shape of the stones.

UIV – Intravenous urology

UIV scan shows the shape of the kidney, renal calyces, ureters; location of stones in the urinary tract; Degree of dilation of the renal calyces, ureters. Thereby, it is possible to determine the contrast-secreting function of the kidneys on each side.

Upstream and downstream renal ureter x-ray

This is a measure to detect non-contrast stones, it is valuable in case of dumb kidney on UIV. film

Bladder endoscopy

This method is rarely used for diagnosis but only used in laparoscopic stone removal surgery

Treatment of kidney stones

Medical treatment to relieve renal colic pain caused by stones

  • Reduce fluid intake during renal colic
  • Pain relief: Doctors often use non-steroidal anti-inflammatory drugs in these cases, intravenous Diclofenac (Voltaire tube 75mg). Some cases are not effective, the doctor will consider the use of Morphine.
  • Smooth muscle relaxants: Intravenous Bus Copan, Drotaverine, …
  • Antibiotics: if there are signs of infection, the most commonly used antibiotics are effective against gram-negative bacteria such as 3rd generation Cephalosporins, Quinolones and Aminoxides. If the patient has renal failure, depending on the degree of renal failure to change the dosage, avoid using Aminoxide
  • Treat the cause of ureteral obstruction (stones, urinary tract malformations causing fluid retention). When medical treatment is not effective for renal colic pain, the doctor will recommend early surgery to clear the blockage. Depending on the patient’s location, the number and size of stones; kidney function status on each side… the doctor will decide to drain the renal pelvis at a minimum, or perform emergency surgery.
  • For small and smooth stones: Urine flow can be increased by diuretics and drinking lots of water, etc. The stone can be expelled naturally by peristalsis of the ureter. use more non-steroidal anti-inflammatory drugs, make the ureteral mucosa not oedematous, avoid obstructing the passage of stones.
  • For uric acid stones – non-contrast stones: common in developed countries. This stone crystallizes in urine pH < 6 and is soluble on alkalization. So, with this type of stone can be treated by:

o Let the patient drink more than 2 litters of water per day, abstain from alcohol and stimulants. The diet needs to be reduced in protein.

o Alkalize urine with Bicarbonate de Sodium drugs 5 -10g/day. Inhibition of purine by Allopurinol 100-300mg/day. Note may cause side effects such as nausea, diarrhea, itching, skin rash, liver failure.

Medical treatment after surgery to remove stones

Patients should note that the treatment of kidney stones does not mean that it will completely stop and not recur. Because, most likely, there will continue to be the following risks:

  • Surgery still has stones left.
  • The urinary tract still has narrow positions, so the urinary system continues to deposit and crystallize to form stones.

 

  • The urinary tract is still infected. Urinary tract infection is one of the causes of kidney stones, so it is necessary to definitively treat urinary tract infections. Ideally, urinary tract infections should be treated according to the antibiotic chart to achieve a radical effect.

Surgical treatment

It is not the patient or the doctor who can completely decide on the treatment method for kidney stones, but because the stone itself, its location and the stage of the disease will decide to apply the appropriate kidney stone surgery method to give the best results. Best results, save cost.

  • When the stone has fallen into the ureter near the bladder, a semi-rigid endoscope and laser can be used to break it and remove it.
  • When the stone is elevated, flexible bronchoscopy can be used. The doctor will use a flexible tube to be inserted through the urethra to access the stone.
  • When the stone is in the middle kidney, use a percutaneous lithotripsy machine to pierce a small hole in the kidney to break the stone. In percutaneous stone removal, the stone is directly removed. If the stone is only 1cm, the doctor can lithotripsy outside the body, less invasive, no hospital stay, cheaper.

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