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KIDNEY STONEI.OVERVIEW 1.What is kidney stone?Kidney stone, also known as urolithiasis, is a condition when a solid piece of material occurs in the urinary tract.The kidneys filter waste products from the blood and add them to the urine that the kidneys produce. When waste materials in the urine do not dissolve completely, crystals and kidney stones may form.Most kidney stones will pass spontanetously through the ureter to the bladder on their own with time but some of them may become sticked in the ureter (then we call them ureterolithiasis). A sticked stone can block the flow of urine, causing pressure to build in the affected ureter and kidney. Increased pressure results in stretching and spasm, which cause the severe pain.2.Who can get kidney stone?One in every 20 people develop kidney stones at some point in their life.Anyone may develop a kidney stone, but people with certain diseases and conditions or those who are taking certain medications are more susceptible to their development. Urinary tract stones are more common in men than in women. Most urinary stones develop in people 20 to 49 years of age, and those who are prone to multiple attacks of kidney stones usually develop their first stones during the second or third decade of life. People who have already had more than one kidney stone are prone to developing further stones. About half of people will have another stone within ten years.A small number of pregnant women develop kidney stones, and there is some evidence that pregnancyrelated changes may increase the risk of stone formation. Factors that may contribute to stone formation during pregnancy include a slowing of the passage of urine due to increased progesterone levels and diminished fluid intake due to a decreasing bladder capacity from the enlarging uterus. Healthy pregnant women also have a mild increase in their urinary calcium excretion. However, it remains unclear whether the changes of pregnancy are directly responsible for kidney stone formation or if these women have another underlying factor that lead them to kidney stone formation.•New words: urinary tract: đường tiết niệuureter: niệu quảnbladder: bàng quangurine: nước tiểuuterus: tử cungexcretion: sự bài tiết II.EPIDEMIOLOGY Kidney stones affect all geographical, cultural, and racial groups. The lifetime risk is about 10 to 15% in the developed world, but can be as high as 20 to 25% in the Middle East.The number of deaths due to kidney stones is estimated at 19,000 per year being consistent between 1990 and 2010.In North America and Europe, the annual number of new cases per year of kidney stones is roughly 0.5%. In the United States, the frequency in the population of urolithiasis has increased from 3.2% to 5.2% from the mid1970s to the mid1990s. In the United States, about 9% of the population has had a kidney stone.In residents of industrialized countries, kidney stones are more common than stones in the bladder. The opposite is true for residents of developing areas of the world, where bladder stones are the most common. This difference is believed to be related to dietary factors.The total cost for treating urolithiasis was 2 billion USD in 2003. About 65–80% of those with kidney stones are men; most stones in women are due to either metabolic defects (such as cystinuria) or infection. Men most commonly experience their first episode between 30 and 40 years of age, whereas for women, the age at first presentation is somewhat later, 35 and 55 years. Recurrence rates are estimated at 50% over a 10year and 75% over 20year period, with some people experiencing ten or more episodes over the course of a lifetime.A 2010 review concluded that rates of disease are increasing.III.SIGNS AND SYMPTOMS Small, smooth kidney stones may remain in the kidney or pass without causing pain (called silent stones). A small stone (usually 4 mm in diameter or less) has a 90 percent chance of passing. Stones that are 8 mm in diameter or larger usually require medical intervention.The feature of a stone that obstructs the ureter or renal pelvis is violent, intermittent pain that radiates from the flank to the groin or to the inner thigh. This pain, known as renal colic, is often described as one of the strongest pain sensations known. Renal colic caused by kidney stones is commonly accompanied by:Blood in the urine (hematuria)Increased frequency of urination (urinary urgency)Nausea and vomitingPain during urination (stinging, burning)Tenderness in the abdomen and kidney regionUrinary tract infection (fever, chills, loss of appetite)KIDNEY STONEI.OVERVIEW 1.What is kidney stone?Kidney stone, also known as urolithiasis, is a condition when a solid piece of material occurs in the urinary tract.The kidneys filter waste products from the blood and add them to the urine that the kidneys produce. When waste materials in the urine do not dissolve completely, crystals and kidney stones may form.Most kidney stones will pass spontanetously through the ureter to the bladder on their own with time but some of them may become sticked in the ureter (then we call them ureterolithiasis). A sticked stone can block the flow of urine, causing pressure to build in the affected ureter and kidney. Increased pressure results in stretching and spasm, which cause the severe pain.2.Who can get kidney stone?One in every 20 people develop kidney stones at some point in their life.Anyone may develop a kidney stone, but people with certain diseases and conditions or those who are taking certain medications are more susceptible to their development. Urinary tract stones are more common in men than in women. Most urinary stones develop in people 20 to 49 years of age, and those who are prone to multiple attacks of kidney stones usually develop their first stones during the second or third decade of life. People who have already had more than one kidney stone are prone to developing further stones. About half of people will have another stone within ten years.A small number of pregnant women develop kidney stones, and there is some evidence that pregnancyrelated changes may increase the risk of stone formation. Factors that may contribute to stone formation during pregnancy include a slowing of the passage of urine due to increased progesterone levels and diminished fluid intake due to a decreasing bladder capacity from the enlarging uterus. Healthy pregnant women also have a mild increase in their urinary calcium excretion. However, it remains unclear whether the changes of pregnancy are directly responsible for kidney stone formation or if these women have another underlying factor that lead them to kidney stone formation.•New words: urinary tract: đường tiết niệuureter: niệu quảnbladder: bàng quangurine: nước tiểuuterus: tử cungexcretion: sự bài tiết II.EPIDEMIOLOGY Kidney stones affect all geographical, cultural, and racial groups. The lifetime risk is about 10 to 15% in the developed world, but can be as high as 20 to 25% in the Middle East.The number of deaths due to kidney stones is estimated at 19,000 per year being consistent between 1990 and 2010.In North America and Europe, the annual number of new cases per year of kidney stones is roughly 0.5%. In the United States, the frequency in the population of urolithiasis has increased from 3.2% to 5.2% from the mid1970s to the mid1990s. In the United States, about 9% of the population has had a kidney stone.In residents of industrialized countries, kidney stones are more common than stones in the bladder. The opposite is true for residents of developing areas of the world, where bladder stones are the most common. This difference is believed to be related to dietary factors.The total cost for treating urolithiasis was 2 billion USD in 2003. About 65–80% of those with kidney stones are men; most stones in women are due to either metabolic defects (such as cystinuria) or infection. Men most commonly experience their first episode between 30 and 40 years of age, whereas for women, the age at first presentation is somewhat later, 35 and 55 years. Recurrence rates are estimated at 50% over a 10year and 75% over 20year period, with some people experiencing ten or more episodes over the course of a lifetime.A 2010 review concluded that rates of disease are increasing.III.SIGNS AND SYMPTOMS Small, smooth kidney stones may remain in the kidney or pass without causing pain (called silent stones). A small stone (usually 4 mm in diameter or less) has a 90 percent chance of passing. Stones that are 8 mm in diameter or larger usually require medical intervention.The feature of a stone that obstructs the ureter or renal pelvis is violent, intermittent pain that radiates from the flank to the groin or to the inner thigh. This pain, known as renal colic, is often described as one of the strongest pain sensations known. Renal colic caused by kidney stones is commonly accompanied by:Blood in the urine (hematuria)Increased frequency of urination (urinary urgency)Nausea and vomitingPain during urination (stinging, burning)Tenderness in the abdomen and kidney regionUrinary tract infection (fever, chills, loss of appetite)It typically comes in waves lasting 20 to 60 minutes caused by peristaltic contractions of the ureter as it attempts to expel the stone. The link between the urinary tract, the genital system, and the gastrointestinal tract is the basis of the radiation of pain to the gonads, as well as the nausea and vomiting that are also common in urolithiasis.Pain in the lower left quadrant can sometimes be confused with diverticulitis because the sigmoid colon overlaps the ureter and the exact location of the pain may be difficult to isolate due to the close proximity of these two structuresPostrenal azotemia and hydronephrosis can be observed following the obstruction of urine flow through one or both ureters. Kidney stone complications include kidney damage and scarring, decreased kidney function, obstruction of the ureter.•New words: diameter đường kínhmedical intervention: can thiệp y họcintermittent: gián đoạngroin: vùng bẹnthigh: đùirenal colic: đau thậnnausea and vomitting: buồn nôn và ói mửaperistaltic contraction: sự co bóp nhu động gonad: tuyến sinh dụcpostrenal azotemia: tăng ure huyết sau thậnhydronephrosis: ứ nướcdiverticulitis: viêm ruột thừasigmoid colon: kết tràng xíchma IV.CAUSES AND RISK FACTORS 1.DehydrationDehydration refers to total body water deficency, with an accompaning disruption of metabolic processes. Dehydration from reduced fluid intake or strenuous exercise without adequate fluid replacement increases the risk of kidney stones. People living in areas with high temperature and humidity have a higher incidence of stone formation.2.DietaryImproper dietary intake of certain substances increases the risk of kidney stone formation a.CalciumCalcium is one component of the most common type of human kidney stones, calcium oxalate. Some studies suggest people who take calcium as a dietary supplement have a higher risk of developing kidney stones.Unlike supplemental calcium, high intakes of dietary calcium do not appear to cause kidney stones and may actually protect against their development. This is perhaps related to the role of calcium in binding ingested oxalate in the gastrointestinal tract. As the amount of calcium intake decreases, the amount of oxalate available for absorption into the bloodstream increases. For most individuals, other risk factors for kidney stones, such as high intakes of dietary oxalates and low fluid intake, play a greater role than calcium intake.b.Other electrolytesCalcium is not the only electrolyte that influences the formation of kidney stones. For example, by increasing urinary calcium excretion, high dietary sodium (Na) may increase the risk of stone formation.Drinking fluoridated tap water may increase the risk of kidney stone formation High dietary intake of potassium appears to reduce the risk of stone formation because potassium (K) promotes the urinary excretion of citrate, an inhibitor of calcium crystal formation.Kidney stones are more likely to develop, and to grow larger, if a person has low dietary magnesium (Mg). Magnesium inhibits stone formation.c.Animal proteinConsumption of animal protein creates an acid load that increases urinary excretion of calcium and uric acid and reduced citrate. Urinary excretion of excess sulfurous amino acids (e.g., cysteine and methionine), uric acid, and other acidic metabolites from animal protein acidifies the urine, which promotes the formation of kidney stones. Low urinary citrate excretion is also commonly found in those with a high dietary intake of animal protein, whereas vegetarians tend to have higher levels of citrate excretion. Low urinary citrate, too, promotes stone formation.d.VitaminsThe evidence linking vitamin C supplements with an increased rate of kidney stones is inconclusive. The excess dietary intake of vitamin C might increase the risk of calcium oxalate stone formation, in practice this is rarely encountered. The link between vitamin D intake and kidney stones is also tenuous. Excessive vitamin D supplementation may increase the risk of stone formation by increasing the intestinal absorption of calcium; correction of a deficiency does not.3.Medical conditionsA number of different medical conditions can lead to an increased risk for developing kidney stones:Urinary tract infection may cause struvite stone formationGout results in chronically increased amount of uric acid in the blood and urine and can lead to the formation of uric acid kidney stonesInherited conditions such as hyperparathyroidism, hypercalciuria (high unrine calcium levels), hyperoxaluria (high unrine oxalate levels), medullary sponge kidney (cystic dilatation of the collecting tubules in kidney), renal tubular acidosis (kidney unable to excrete acid)...Chronic diseases such as diabetes and high blood pressure (hypertension) are also associated with an increased risk of developing kidney stones.Obesity is a leading risk factor as well.•New words: Strenous: kịch liệtexcrete: bài tiếtelectrolyte: chất điện liacidify: axit hoácystic: (thuộc) nangdilatation: sự giãn nỡcolleting tubule: ống góp (của thận) V.PATHOPHYSIOLOGICAL 1.Four stages of stone formation:Stage 1:NucleationWhen the urine becomes supersaturated (when the urine solvent contains more solutes than it can hold in solution) with one or more crystalforming substances, ions will spontaneously join together to form a solid crystal, this is called nucleation.There are two kinds of nucleation: ho and. In homogeneous nucleation, crystals form around the nucleus with the same composition, crystals of a different composition can also form around the nucleus. In heterogeneous nucleation, organic material such as cell debris may be deposited between the crystal as a matrix. Heterogeneous nucleation proceeds more rapidly than homeogeneous nucletion because it requires less energy.Stage 2: GrowthThe tiny crystal formations travel down the nephron and they are usually deposited at the renal papilla.Stage 3: AggregationCrystals that have already form then begin to stick together forming large stones.Stage 4: RetentionNew stones are retained in the kidney where they can continue to grow for an unspecified length of time until they are displaced and travel through the kidney in to the ureter.If a stone continues to grow until it reaches a critical size (45mm in diameter), it may be too large to pass easily through the ureter. The edges of the stone may become stuck inside the ureter at three constriction of the ureter: at the junction of the renal pelvis and the ureter, where the ureter crosses over the iliac artery, at the juntion as the ureter enters the bladder wall.2.Factors involved stone formationDepending on the chemical composition of the crystal, the stoneforming process may proceed more rapidly when the urine pH is unusually high or low. For example, at a pH of 7.0, the solubility of uric acid in urine is 158 mg100 ml. Reducing the pH to 5.0 decreases the solubility of uric acid to less than 8 mg100 ml. The formation of uric acid stones requires a combination of hyperuricosuria (high urine uric acid levels) and low urine pH; hyperuricosuria alone is not associated with uric acid stone formation if the urine pH is alkaline. Supersaturation of the urine is a necessary, but not a sufficient, condition for the development of any urinary stone formation. Supersaturation is likely the underlying cause of uric acid and cystine stones, but calciumbased stones (especially calcium oxalate stones) may have a more complex cause.Urine normally contains chemicals citrate, magnesium, pyrophosphate that help prevent the formation of crystals and stones. Low levels of these inhibitors can contribute to the formation of kidney stones. Of these, citrate is the most important.•New words: supersaturation: sự siêu bão hoàsolvent: dung môisolute: chất tansolution: dung dịchrenal papilla: nhú thậnalkaline: kiềm tính VI.CLASSIFICATION Kidney stones are typically classified by their chemical composition1.Calcium containing stonesBy far, the most common type of kidney stones worldwide contains calcium, represent about 80% of all cases; these typically contain calcium oxalate either alone or in combination with calcium phosphate in the form of apatite or brushite. Factors that promote the precipitation of oxalate crystals in the urine, such as primary hyperoxaluria, are associated with the development of calcium oxalate stones. The formation of calcium phosphate stones is associated with conditions such as hyperparathyroidism and renal tubular acidosis.Calcium oxalate crystals in urine appear as envelopes microscopically. They may also form dumbbells.2.Struvite stonesAbout 10–15% of urinary calculi are composed of struvite (ammonium magnesium phosphate, NH4MgPO4·6H2O). Struvite stones (also known as infection stones, urease or triplephosphate stones), form most often in the presence of infection by ureasplitting bacteria. Using the enzyme urease, these organisms metabolize urea into ammonia and carbon dioxide. This alkalinizes the urine, resulting in favorable conditions for the formation of struvite stones.These infection stones are commonly observed in people who have factors that lead them to urinary tract infections, such as those with spinal cord injury. They are also commonly seen in people with underlying metabolic disorders, such as idiopathic hypercalciuria, hyperparathyroidism, and gout. Infection stones can grow rapidly, forming large calyceal staghorn (antlershaped) stone requiring invasive surgery such as percutaneous nephrolithotomy (procedure to remove stones from the kidney by a small puncture wound through the skin) for final treatment.Struvite stones have a coffin lid morphology by microscopy.3.Uric acid stonesAbout 5–10% of all stones are formed from uric acid. People with certain metabolic abnormalities, including obesity, may produce uric acid stones.They may also form in association with disorders of acidbase metabolism where the urine is excessively acidic (low pH), resulting in precipitation of uric acid crystals.Uric acid stones appear as pleomorphic crystals, usually diamondshaped. They may also look like squares or rods which are polarizable (ability to form dipoles).Patients with hyperuricosuria can be treated with allopurinol which will reduce urate formation. Urine alkalinization may also be helpful in this setting.4.OthersPeople with certain rare n errors of metabolism have a trend to accumulate crystalforming substances in their urine. For example, those with cystinuria, cystinosis, and Fanconi syndrome may form stones composed of cystine. Cystine stone formation can be treated with urine alkalinization and dietary protein restriction. People afflicted with xanthinuria often produce stones composed of xanthine.•New words: precipitation: sự kết tủa renal tubular acidosis: toan ống thậnevelope: hình bao (toán học)dumbbells: quả tạspinal cord: tuỷ sốngidiopathic: vô căninvasive: xâm lấndilope: lưỡng cực VII.DIAGNOSIS a)Imaging studiesIn people with a history of stones, who are less than 50 years of age and are presenting with the symptoms of stones without any concerning signs do not require helical CT scan imaging.Otherwise, a helical CT scan is the diagnostic modality of choice in the radiographic evaluation of suspected kidney stone. All stones are detectable on CT scans except very rare stones composed of certain drug residues in the urine. Calciumcontaining stones are relatively radiodense (or radiopaque inhibit the passage of electromagnetic radiation), and they can often be detected by a traditional radiograph of the abdomen that includes the kidneys, ureters, and bladder (KUB film). Some 60% of all renal stones are radiodense. In general, calcium phosphate stones have the greatest density, followed by calcium oxalate and magnesium ammonium phosphate stones. Cystine stones are only radiodense, while uric acid stones are usually entirely radiolucent (allow radation to pass more freely).When a CT scan is unavailable, an intravenous pyelogram may be performed to help confirm the diagnosis of urolithiasis. This involves intravenous injection of a contrast agent followed by a KUB film. Stones present in the kidneys, ureters or bladder may be better defined by the use of this contrast agent. Stones can also be detected by a retrograde pyelogram, where a similar contrast agent is injected directly into the distal ostium of the ureter (where the ureter terminates as it enters the bladder).Ultrasound imaging of the kidneys can sometimes be useful, as it gives details about the presence of hydronephrosis, suggesting the stone is blocking the outflow of urine. Radiolucent stones, which do not appear on KUB, may show up on ultrasound imaging studies. Other advantages of renal ultrasonography include its low cost and absence of radiation exposure. Ultrasound imaging is useful for detecting stones in situations where Xrays or CT scans are discouraged, such as in children or pregnant women. Despite these advantages, renal ultrasonography in 2009 was not considered a substitute for noncontrast helical CT scan in the initial diagnostic evaluation of urolithiasis. The main reason for this is that compared with CT, renal ultrasonography more often fails to detect small stones (especially ureteral stones), as well as other serious disorders that could be causing the symptoms.b)Laboratory examinationLaboratory investigations typically carried out include: Microscopic examination of the urine, which may show red blood cells, bacteria, leukocytes, urinary casts and crystals;Urine culture to identify any infecting organisms present in the urinary tract and determine the susceptibility of these organisms to specific antibiotics;Complete blood count, looking for neutrophilia (increased neutrophil granulocyte count) suggestive of bacterial infection, as seen in the setting of struvite stones;Renal function tests to look for abnormally high blood calcium blood levels (hypercalcemia);24 hour urine collection to measure total daily urinary volume, magnesium, sodium, uric acid, calcium, citrate, oxalate and phosphate;Collection of stones (by urinating through a StoneScreen kidney stone collection cup or a simple tea strainer) is useful. Chemical analysis of collected stones can establish their composition, which in turn can help to guide future prevention and management.•New words:modality: phương thứcevaluation: sự đánh giáresidue: chất cặndensity: tỉ trọnghydronephrosis: ứ nướcexplosure: phơi sángVIII.MANAGEMENT 1.Pain managementManagement of pain often requires intravenous injection of NSAIDs or opioids. Oral medication are often effective for less severe discomfort. The use of antispasmodics does not have further benefit2.Expulsion theraphy
KIDNEY STONE I OVERVIEW What is kidney stone? Kidney stone, also known as urolithiasis, is a condition when a solid piece of material occurs in the urinary tract The kidneys filter waste products from the blood and add them to the urine that the kidneys produce When waste materials in the urine not dissolve completely, crystals and kidney stones may form Most kidney stones will pass spontanetously through the ureter to the bladder on their own with time but some of them may become sticked in the ureter (then we call them ureterolithiasis) A sticked stone can block the flow of urine, causing pressure to build in the affected ureter and kidney Increased pressure results in stretching and spasm, which cause the severe pain Who can get kidney stone? One in every 20 people develop kidney stones at some point in their life Anyone may develop a kidney stone, but people with certain diseases and conditions or those who are taking certain medications are more susceptible to their development Urinary tract stones are more common in men than in women Most urinary stones develop in people 20 to 49 years of age, and those who are prone to multiple attacks of kidney stones usually develop their first stones during the second or third decade of life People who have already had more than one kidney stone are prone to developing further stones About half of people will have another stone within ten years A small number of pregnant women develop kidney stones, and there is some evidence that pregnancy-related changes may increase the risk of stone formation Factors that may contribute to stone formation during pregnancy include a slowing of the passage of urine due to increased progesterone levels and diminished fluid intake due to a decreasing bladder capacity from the enlarging uterus Healthy pregnant women also have a mild increase in their urinary calcium excretion However, it remains unclear whether the changes of pregnancy are directly responsible for kidney stone formation or if these women have another underlying factor that lead them to kidney stone formation • New words: - urinary tract: đường tiết niệu - ureter: niệu quản - bladder: bàng quang II - urine: nước tiểu - uterus: tử cung - excretion: tiết EPIDEMIOLOGY Kidney stones affect all geographical, cultural, and racial groups The lifetime risk is about 10 to 15% in the developed world, but can be as high as 20 to 25% in the Middle East The number of deaths due to kidney stones is estimated at 19,000 per year being consistent between 1990 and 2010 In North America and Europe, the annual number of new cases per year of kidney stones is roughly 0.5% In the United States, the frequency in the population of urolithiasis has increased from 3.2% to 5.2% from the mid-1970s to the mid-1990s In the United States, about 9% of the population has had a kidney stone In residents of industrialized countries, kidney stones are more common than stones in the bladder The opposite is true for residents of developing areas of the world, where bladder stones are the most common This difference is believed to be related to dietary factors The total cost for treating urolithiasis was billion USD in 2003 About 65–80% of those with kidney stones are men; most stones in women are due to either metabolic defects (such as cystinuria) or infection Men most commonly experience their first episode between 30 and 40 years of age, whereas for women, the age at first presentation is somewhat later, 35 and 55 years Recurrence rates are estimated at 50% over a 10-year and 75% over 20-year period, with some people experiencing ten or more episodes over the course of a lifetime A 2010 review concluded that rates of disease are increasing III SIGNS AND SYMPTOMS Small, smooth kidney stones may remain in the kidney or pass without causing pain (called "silent" stones) A "small" stone (usually mm in diameter or less) has a 90 percent chance of passing Stones that are mm in diameter or larger usually require medical intervention The feature of a stone that obstructs the ureter or renal pelvis is violent, intermittent pain that radiates from the flank to the groin or to the inner thigh This pain, known as renal colic, is often described as one of the strongest pain sensations known Renal colic caused by kidney stones is commonly accompanied by: - Blood in the urine (hematuria) - Increased frequency of urination (urinary urgency) - Nausea and vomiting - Pain during urination (stinging, burning) - Tenderness in the abdomen and kidney region - Urinary tract infection (fever, chills, loss of appetite) It typically comes in waves lasting 20 to 60 minutes caused by peristaltic contractions of the ureter as it attempts to expel the stone The link between the urinary tract, the genital system, and the gastrointestinal tract is the basis of the radiation of pain to the gonads, as well as the nausea and vomiting that are also common in urolithiasis Pain in the lower left quadrant can sometimes be confused with diverticulitis because the sigmoid colon overlaps the ureter and the exact location of the pain may be difficult to isolate due to the close proximity of these two structures Postrenal azotemia and hydronephrosis can be observed following the obstruction of urine flow through one or both ureters Kidney stone complications include kidney damage and scarring, decreased kidney function, obstruction of the ureter • New words: - diameter đường kính - medical intervention: can thiệp y học - intermittent: gián đoạn - groin: vùng bẹn - thigh: đùi - renal colic: đau thận - nausea and vomitting: buồn nôn - postrenal azotemia: tăng ure huyết ói mửa - peristaltic contraction: co bóp sau thận - hydronephrosis: ứ nước - diverticulitis: viêm ruột thừa - sigmoid colon: kết tràng xích-ma nhu động - gonad: tuyến sinh dục IV CAUSES AND RISK FACTORS Dehydration Dehydration refers to total body water deficency, with an accompaning disruption of metabolic processes Dehydration from reduced fluid intake or strenuous exercise without adequate fluid replacement increases the risk of kidney stones People living in areas with high temperature and humidity have a higher incidence of stone formation Dietary Improper dietary intake of certain substances increases the risk of kidney stone formation a Calcium Calcium is one component of the most common type of human kidney stones, calcium oxalate Some studies suggest people who take calcium as a dietary supplement have a higher risk of developing kidney stones Unlike supplemental calcium, high intakes of dietary calcium not appear to cause kidney stones and may actually protect against their development This is perhaps related to the role of calcium in binding ingested oxalate in the gastrointestinal tract As the amount of calcium intake decreases, the amount of oxalate available for absorption into the bloodstream increases For most individuals, other risk factors for kidney stones, such as high intakes of dietary oxalates and low fluid intake, play a greater role than calcium intake b Other electrolytes Calcium is not the only electrolyte that influences the formation of kidney stones For example, by increasing urinary calcium excretion, high dietary sodium (Na) may increase the risk of stone formation Drinking fluoridated tap water may increase the risk of kidney stone formation High dietary intake of potassium appears to reduce the risk of stone formation because potassium (K) promotes the urinary excretion of citrate, an inhibitor of calcium crystal formation Kidney stones are more likely to develop, and to grow larger, if a person has low dietary magnesium (Mg) Magnesium inhibits stone formation c Animal protein Consumption of animal protein creates an acid load that increases urinary excretion of calcium and uric acid and reduced citrate Urinary excretion of excess sulfurous amino acids (e.g., cysteine and methionine), uric acid, and other acidic metabolites from animal protein acidifies the urine, which promotes the formation of kidney stones Low urinary citrate excretion is also commonly found in those with a high dietary intake of animal protein, whereas vegetarians tend to have higher levels of citrate excretion Low urinary citrate, too, promotes stone formation d Vitamins The evidence linking vitamin C supplements with an increased rate of kidney stones is inconclusive The excess dietary intake of vitamin C might increase the risk of calcium oxalate stone formation, in practice this is rarely encountered The link between vitamin D intake and kidney stones is also tenuous Excessive vitamin D supplementation may increase the risk of stone formation by increasing the intestinal absorption of calcium; correction of a deficiency does not Medical conditions A number of different medical conditions can lead to an increased risk for developing kidney stones: - Urinary tract infection may cause struvite stone formation - Gout results in chronically increased amount of uric acid in the blood and urine and can lead to the formation of uric acid kidney stones - Inherited conditions such as hyperparathyroidism, hypercalciuria (high unrine calcium levels), hyperoxaluria (high unrine oxalate levels), medullary sponge kidney (cystic dilatation of the collecting tubules in kidney), renal tubular acidosis (kidney unable to excrete acid) - Chronic diseases such as diabetes and high blood pressure (hypertension) are also associated with an increased risk of developing kidney stones - Obesity is a leading risk factor as well • New words: - V Strenous: kịch liệt excrete: tiết electrolyte: chất điện li acidify: axit hoá - cystic: (thuộc) nang - dilatation: giãn nỡ - colleting tubule: ống góp (của thận) PATHOPHYSIOLOGICAL Four stages of stone formation: Stage 1:Nucleation When the urine becomes supersaturated (when the urine solvent contains more solutes than it can hold in solution) with one or more crystal-forming substances, ions will spontaneously join together to form a solid crystal, this is called nucleation There are two kinds of nucleation: ho and In homogeneous nucleation, crystals form around the nucleus with the same composition, crystals of a different composition can also form around the nucleus In heterogeneous nucleation, organic material such as cell debris may be deposited between the crystal as a matrix Heterogeneous nucleation proceeds more rapidly than homeogeneous nucletion because it requires less energy Stage 2: Growth The tiny crystal formations travel down the nephron and they are usually deposited at the renal papilla Stage 3: Aggregation Crystals that have already form then begin to stick together forming large stones Stage 4: Retention New stones are retained in the kidney where they can continue to grow for an unspecified length of time until they are displaced and travel through the kidney in to the ureter If a stone continues to grow until it reaches a critical size (4-5mm in diameter), it may be too large to pass easily through the ureter The edges of the stone may become stuck inside the ureter at three constriction of the ureter: at the junction of the renal pelvis and the ureter, where the ureter crosses over the iliac artery, at the juntion as the ureter enters the bladder wall Factors involved stone formation Depending on the chemical composition of the crystal, the stone-forming process may proceed more rapidly when the urine pH is unusually high or low For example, at a pH of 7.0, the solubility of uric acid in urine is 158 mg/100 ml Reducing the pH to 5.0 decreases the solubility of uric acid to less than mg/100 ml The formation of uric acid stones requires a combination of hyperuricosuria (high urine uric acid levels) and low urine pH; hyperuricosuria alone is not associated with uric acid stone formation if the urine pH is alkaline Supersaturation of the urine is a necessary, but not a sufficient, condition for the development of any urinary stone formation Supersaturation is likely the underlying cause of uric acid and cystine stones, but calcium-based stones (especially calcium oxalate stones) may have a more complex cause Urine normally contains chemicals - citrate, magnesium, pyrophosphate - that help prevent the formation of crystals and stones Low levels of these inhibitors can contribute to the formation of kidney stones Of these, citrate is the most important • New words: - supersaturation: siêu bão hoà - solvent: dung môi - solute: chất tan - solution: dung dịch - renal papilla: nhú thận - alkaline: kiềm tính VI CLASSIFICATION Kidney stones are typically classified by their chemical composition Calcium containing stones By far, the most common type of kidney stones worldwide contains calcium, represent about 80% of all cases; these typically contain calcium oxalate either alone or in combination with calcium phosphate in the form of apatite or brushite Factors that promote the precipitation of oxalate crystals in the urine, such as primary hyperoxaluria, are associated with the development of calcium oxalate stones The formation of calcium phosphate stones is associated with conditions such as hyperparathyroidism and renal tubular acidosis Calcium oxalate crystals in urine appear as 'envelopes' microscopically They may also form 'dumbbells.' Struvite stones About 10–15% of urinary calculi are composed of struvite (ammonium magnesium phosphate, NH4MgPO4·6H2O) Struvite stones (also known as "infection stones", urease or triple-phosphate stones), form most often in the presence of infection by urea-splitting bacteria Using the enzyme urease, these organisms metabolize urea into ammonia and carbon dioxide This alkalinizes the urine, resulting in favorable conditions for the formation of struvite stones These infection stones are commonly observed in people who have factors that lead them to urinary tract infections, such as those with spinal cord injury They are also commonly seen in people with underlying metabolic disorders, such as idiopathic hypercalciuria, hyperparathyroidism, and gout Infection stones can grow rapidly, forming large calyceal staghorn (antler-shaped) stone requiring invasive surgery such as percutaneous nephrolithotomy (procedure to remove stones from the kidney by a small puncture wound through the skin) for final treatment Struvite stones have a 'coffin lid' morphology by microscopy Uric acid stones About 5–10% of all stones are formed from uric acid People with certain metabolic abnormalities, including obesity, may produce uric acid stones.They may also form in association with disorders of acid/base metabolism where the urine is excessively acidic (low pH), resulting in precipitation of uric acid crystals Uric acid stones appear as pleomorphic crystals, usually diamond-shaped They may also look like squares or rods which are polarizable (ability to form dipoles) Patients with hyperuricosuria can be treated with allopurinol which will reduce urate formation Urine alkalinization may also be helpful in this setting Others People with certain rare n errors of metabolism have a trend to accumulate crystalforming substances in their urine For example, those with cystinuria, cystinosis, and Fanconi syndrome may form stones composed of cystine Cystine stone formation can be treated with urine alkalinization and dietary protein restriction People afflicted with xanthinuria often produce stones composed of xanthine • New words: - precipitation: kết tủa - renal tubular acidosis: toan ống thận - evelope: hình bao (toán học) - dumbbells: tạ spinal cord: tuỷ sống idiopathic: vô invasive: xâm lấn dilope: lưỡng cực VII DIAGNOSIS a) Imaging studies In people with a history of stones, who are less than 50 years of age and are presenting with the symptoms of stones without any concerning signs not require helical CT scan imaging Otherwise, a helical CT scan is the diagnostic modality of choice in the radiographic evaluation of suspected kidney stone All stones are detectable on CT scans except very rare stones composed of certain drug residues in the urine Calcium-containing stones are relatively radiodense (or radiopaque - inhibit the passage of electromagnetic radiation), and they can often be detected by a traditional radiograph of the abdomen that includes the kidneys, ureters, and bladder (KUB film) Some 60% of all renal stones are radiodense In general, calcium phosphate stones have the greatest density, followed by calcium oxalate and magnesium ammonium phosphate stones Cystine stones are only radiodense, while uric acid stones are usually entirely radiolucent (allow radation to pass more freely) When a CT scan is unavailable, an intravenous pyelogram may be performed to help confirm the diagnosis of urolithiasis This involves intravenous injection of a contrast agent followed by a KUB film Stones present in the kidneys, ureters or bladder may be better defined by the use of this contrast agent Stones can also be detected by a retrograde pyelogram, where a similar contrast agent is injected directly into the distal ostium of the ureter (where the ureter terminates as it enters the bladder) Ultrasound imaging of the kidneys can sometimes be useful, as it gives details about the presence of hydronephrosis, suggesting the stone is blocking the outflow of urine Radiolucent stones, which not appear on KUB, may show up on ultrasound imaging studies Other advantages of renal ultrasonography include its low cost and absence of radiation exposure Ultrasound imaging is useful for detecting stones in situations where X-rays or CT scans are discouraged, such as in children or pregnant women Despite these advantages, renal ultrasonography in 2009 was not considered a substitute for noncontrast helical CT scan in the initial diagnostic evaluation of urolithiasis The main reason for this is that compared with CT, renal ultrasonography more often fails to detect small stones (especially ureteral stones), as well as other serious disorders that could be causing the symptoms b) Laboratory examination Laboratory investigations typically carried out include: 10 - Microscopic examination of the urine, which may show red blood cells, bacteria, leukocytes, urinary casts and crystals; - Urine culture to identify any infecting organisms present in the urinary tract and determine the susceptibility of these organisms to specific antibiotics; - Complete blood count, looking for neutrophilia (increased neutrophil granulocyte count) suggestive of bacterial infection, as seen in the setting of struvite stones; - Renal function tests to look for abnormally high blood calcium blood levels (hypercalcemia); - 24 hour urine collection to measure total daily urinary volume, magnesium, sodium, uric acid, calcium, citrate, oxalate and phosphate; - Collection of stones (by urinating through a StoneScreen kidney stone collection cup or a simple tea strainer) is useful Chemical analysis of collected stones can establish their composition, which in turn can help to guide future prevention and management • New words: - modality: phương thức - evaluation: đánh giá - residue: chất cặn - density: tỉ trọng - hydronephrosis: ứ nước - explosure: phơi sáng VIII MANAGEMENT Pain management Management of pain often requires intravenous injection of NSAIDs or opioids Oral medication are often effective for less severe discomfort The use of antispasmodics does not have further benefit Expulsion theraphy The use of medications to speed the spontaneous passage of stones in the ureter is referred to as medical expulsive therapy Several agents, including alphaadrenergic blockers (such as tamsulosin) and calcium channel blockers (such as nifedipine), have been found to be effective Alpha-blockers appear to lead to both higher and faster stone clearance rates Alpha-blockers, however, only appear to be 11 effective for stones over mm but less than 10 mm in size A combination of tamsulosin and a corticosteroid may be better than tamsulosin alone These treatments also appear to be a useful extra to lithotripsy Lithotripsy Extracorporeal shock wave lithotripsy (ESWL) is a noninvasive technique for the removal of kidney stones Most ESWL is carried out when the stone is present near the renal pelvis ESWL involves the use of a machine to deliver externally applied, focused, high-intensity pulses of ultrasonic energy to cause fragmentation of a stone over a period of around 30–60 minutes Then, the tiny pieces of stone can pass out of the body in the urine ESWL is currently used in the treatment of uncomplicated stones located in the kidney and upper ureter Some 80 to 85% of simple renal stone can be effectively treated with ESWL For a stone greater than 10 mm , ESWL may not help break the stone in one treatment; instead, two or three treatments may be needed A number of factors can influence its efficacy, including chemical composition of the stone, presence of abnormal renal anatomy and the specific location of the stone within the kidney, presence of hydronephrosis, body mass index, and distance of the stone from the surface of the skin Common adverse effects of ESWL include acute trauma, such as bruising at the site of shock administration, and damage to blood vessels of the kidney In fact, most of people who are treated with a typical dose of shock waves using currently accepted treatment settings are likely to experience some degree of acute kidney injury ESWL-induced acute kidney injury is dose dependent and can be severe, including internal bleeding and subcapsular hematomas Ureteroscphic surgery A ureteroscopy is an examination or procedure using a ureteroscope A ureteroscope is an instrument for examining the inside of the urinary tract.Some ureteroscopes are flexible like a thin, long straw Others are more rigid and firm Through the ureteroscope, the doctor can see a stone in the ureter and then remove 12 it with a small basket at the end of a wire inserted through an extra channel in the ureteroscope Another way to treat a stone through a ureteroscope is to extend a flexible fiber through the scope up to the stone and then, with a laser beam shone through the fiber, break the stone into smaller pieces that can then pass out of the body in the urine Ureteroscopic techniques are generally more effective than ESWL for treating stones located in the lower ureter, with success rates of 93–100% Although ESWL has been traditionally preferred by many practitioners for treating stones located in the upper ureter, more recent experience suggests ureteroscopic techniques offer distinct advantages in the treatment of upper ureteral stones Specifically, the overall success rate is higher, fewer repeat interventions and postoperative visits are needed, and treatment costs are lower after ureteroscopic treatment when compared with ESWL • New words: - inpulsion: trục xuất - lithotripsy: tán sỏi - extracorporeal: bên thể - high-intensity : cường độ cao - uncomplicated: không biến chứng IX - adverse: bất lợi - acute trauma: chấn thương cấp tính - bruishing: bầm tím - subcapsular hematomas: máu tụ bao - postoperative: sau phẫu thuật PREVENTION Diatary measures Specific therapy should be proper to the type of stones involved Diet can have a great influence on the development of kidney stones Preventive strategies include some combination of dietary modifications and medications with the goal of reducing the excretory load of calculogenic compounds on the kidneys Current dietary recommendations to minimize the formation of kidney stones include: 13 - Increasing total fluid intake to more than two liters per day of urine output If you live in a hot, dry climate or you exercise frequently, you may need to drink even more water to produce enough urine If your urine is light and clear, you're likely drinking enough water - Increasing citric acid intake; lemon/lime juice is the richest natural source - Moderate calcium intake: continue eating calcium-rich foods, but use caution with calcium supplements - Limiting sodium intake (salt) - Avoidance of large doses of supplemental vitamin C - Limiting animal protein intake and choose nonanimal protein source such as legumes - Limiting consumption of cola soft drinks, which contain phosphoric acid, to less than one liter of soft drink per week Medication Medications can control the amount of minerals and acid in your urine and may be helpful in people who form certain kinds of stones The type of medication your doctor prescribes will depend on the kind of kidney stones you have Here are some examples: - Calcium stones: To help prevent calcium stones from forming, your doctor may prescribe a thiazide diuretic or a phosphate-containing preparation - Uric acid stones: Your doctor may prescribe allopurinol (Zyloprim, Aloprim) to reduce uric acid levels in your blood and urine and a medicine to keep your urine alkaline In some cases, allopurinol and an alkalizing agent may dissolve the uric acid stones - Struvite stones: To prevent struvite stones, your doctor may recommend strategies to keep your urine free of bacteria that cause infection Long-term use of antibiotics in small doses may help achieve this goal For instance, your doctor may recommend an antibiotic before and for a while after surgery to treat your kidney stones - Cystine stones: Cystine stones can be difficult to treat Your doctor may recommend that you drink more fluids so that you produce a lot more urine 14 If that alone doesn't help, your doctor may also prescribe a medication that decreases the amount of cystine in your urine 15 [...]... dissolve the uric acid stones - Struvite stones: To prevent struvite stones, your doctor may recommend strategies to keep your urine free of bacteria that cause infection Long-term use of antibiotics in small doses may help achieve this goal For instance, your doctor may recommend an antibiotic before and for a while after surgery to treat your kidney stones - Cystine stones: Cystine stones can be difficult... the treatment of uncomplicated stones located in the kidney and upper ureter Some 80 to 85% of simple renal stone can be effectively treated with ESWL For a stone greater than 10 mm , ESWL may not help break the stone in one treatment; instead, two or three treatments may be needed A number of factors can influence its efficacy, including chemical composition of the stone, presence of abnormal renal... therapy should be proper to the type of stones involved Diet can have a great influence on the development of kidney stones Preventive strategies include some combination of dietary modifications and medications with the goal of reducing the excretory load of calculogenic compounds on the kidneys Current dietary recommendations to minimize the formation of kidney stones include: 13 - Increasing total... urine and may be helpful in people who form certain kinds of stones The type of medication your doctor prescribes will depend on the kind of kidney stones you have Here are some examples: - Calcium stones: To help prevent calcium stones from forming, your doctor may prescribe a thiazide diuretic or a phosphate-containing preparation - Uric acid stones: Your doctor may prescribe allopurinol (Zyloprim, Aloprim)... struvite stones; - Renal function tests to look for abnormally high blood calcium blood levels (hypercalcemia); - 24 hour urine collection to measure total daily urinary volume, magnesium, sodium, uric acid, calcium, citrate, oxalate and phosphate; - Collection of stones (by urinating through a StoneScreen kidney stone collection cup or a simple tea strainer) is useful Chemical analysis of collected stones... (ESWL) is a noninvasive technique for the removal of kidney stones Most ESWL is carried out when the stone is present near the renal pelvis ESWL involves the use of a machine to deliver externally applied, focused, high-intensity pulses of ultrasonic energy to cause fragmentation of a stone over a period of around 30–60 minutes Then, the tiny pieces of stone can pass out of the body in the urine ESWL is... Through the ureteroscope, the doctor can see a stone in the ureter and then remove 12 it with a small basket at the end of a wire inserted through an extra channel in the ureteroscope Another way to treat a stone through a ureteroscope is to extend a flexible fiber through the scope up to the stone and then, with a laser beam shone through the fiber, break the stone into smaller pieces that can then pass... presence of abnormal renal anatomy and the specific location of the stone within the kidney, presence of hydronephrosis, body mass index, and distance of the stone from the surface of the skin Common adverse effects of ESWL include acute trauma, such as bruising at the site of shock administration, and damage to blood vessels of the kidney In fact, most of people who are treated with a typical dose... are generally more effective than ESWL for treating stones located in the lower ureter, with success rates of 93–100% Although ESWL has been traditionally preferred by many practitioners for treating stones located in the upper ureter, more recent experience suggests ureteroscopic techniques offer distinct advantages in the treatment of upper ureteral stones Specifically, the overall success rate is higher,... spontaneous passage of stones in the ureter is referred to as medical expulsive therapy Several agents, including alphaadrenergic blockers (such as tamsulosin) and calcium channel blockers (such as nifedipine), have been found to be effective Alpha-blockers appear to lead to both higher and faster stone clearance rates Alpha-blockers, however, only appear to be 11 effective for stones over 4 mm but less ... smooth kidney stones may remain in the kidney or pass without causing pain (called "silent" stones) A "small" stone (usually mm in diameter or less) has a 90 percent chance of passing Stones... United States, about 9% of the population has had a kidney stone In residents of industrialized countries, kidney stones are more common than stones in the bladder The opposite is true for residents... kiềm tính VI CLASSIFICATION Kidney stones are typically classified by their chemical composition Calcium containing stones By far, the most common type of kidney stones worldwide contains calcium,