PAUL K. PIETROW, M.D., and MICHAEL E. KARELLAS, M.D., college of Kansas clinical Center, Kansas City, Kansas

Am Fam Physician. 2006 Jul 1;74(1):86-94.

You are watching: The treatment of renal calculi might include

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patient information: See related handout top top kidney stones, written by the authors of this article.


Nephrolithiasis is a usual condition affecting practically 5 percent that U.S. Men and also women throughout their lifetimes. Recurrent calculi deserve to be impede in many patients by the usage of a streamlined evaluation, reasonable dietary and also fluid recommendations, and also directed pharmacologic intervention. Serum studies and 24-hour urine collections space the mainstays that metabolic investigation and usually space warranted in patients through recurrent calculi. Although part stones space the result of inherited conditions, most an outcome from a complex interaction between diet, liquid habits, and genetic predisposition. Calcium-sparing diuretics such as thiazides often are used to treat hypercalciuria. Citrate medications increase levels the this normally occurring rock inhibitor. Allopurinol deserve to be advantageous in patients v hyperuricosuria, and urease inhibitors can help break the bicycle of contagious calculi. Aggressive fluid intake and also moderated intake of salt, calcium, and also meat are recommended for many patients.


Urinary stone an illness is a far-ranging health difficulty in the unified States, v an estimated expense of $2 exchange rate (based ~ above 2003 dollars) every year.1 although surgical administration has end up being increasingly tolerable, clinical prevention of recurrent calculi is feasible, conveniently obtained, and also greatly desirable.


SORT: key RECOMMENDATIONS for PRACTICEClinical recommendationEvidence ratingReferencesComments

Physicians have to advise patients to boost their water intake to mitigate the danger of recurrence of urinary calculi and also to expand the typical interval the recurrence.

B

11,12

Findings native one prospective trial and usual clinical practice

Physicians need to advise patient to limit their intake of sodium and also animal protein to alleviate the danger of occurring urinary calculi.

A

13–15

Supported by prospective trials and large population studies

Potassium citrate (Urocit-K) have to be administered come decrease the risk of developing calcium oxalate stones.

B

19

Findings native one randomized trial and usual clinical practice


A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, normal practice, expert opinion, or situation series. Because that information about the SORT proof rating system, see page 17 orhttps://www.wgc2010.org/afpsort.xml.


SORT: vital RECOMMENDATIONS for PRACTICEClinical recommendationEvidence ratingReferencesComments

Physicians must advise patient to increase their water input to mitigate the risk of recurrence of urinary calculi and also to extend the typical interval the recurrence.

B

11,12

Findings native one prospective trial and usual clinical practice

Physicians need to advise patients to limit their intake of sodium and animal protein to mitigate the hazard of occurring urinary calculi.

A

13–15

Supported through prospective trials and large population studies

Potassium citrate (Urocit-K) have to be administered come decrease the threat of arising calcium oxalate stones.

B

19

Findings native one randomized trial and usual clinical practice


A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, normal practice, professional opinion, or case series. For information about the SORT evidence rating system, see web page 17 orhttps://www.wgc2010.org/afpsort.xml.


The pervasiveness of urinary calculi is estimated to be 5 percent in the general population, with an annual incidence the as much as 1 percent.2 males are double as most likely as women to develop calculi, v the very first episode arising at one average period of 30 years.3 Women have actually a bimodal age of onset, v episodes peaking at 35 and also 55 years. Without preventive treatment, the recurrence price of calcium oxalate calculi rises with time and reaches 50 percent at 10 years.3


Renal calculi room crystalline mineral deposits that type in the kidney. They build from microscopic crystals in the loop the Henle, the distal tubule, or the collecting duct, and they have the right to enlarge to type visible fragments.3 The process of rock formation relies on urinary volume; concentration of calcium, phosphate, oxalate, sodium, and also uric mountain ions; concentrations of natural calculus inhibitors (e.g., citrate, magnesium, Tamm-Horsfall mucoproteins, bikunin); and also urinary pH.4 High ion levels, low urinary volume, low pH, and low citrate levels donate calculus formation. Hazard factors and also their instrument of action are provided in Table 1.


TABLE 1Risk components for the breakthrough of Urinary CalculiRisk factorMechanisms

Bowel disease

Promotes low urine volume; acidic to pee depletes accessible citrate; hyperoxaluria

Excess diet meat (including poultry)

Creates acidic urinary milieu, depletes available citrate; disclosure hyperuricosuria

Excess diet oxalate

Promotes hyperoxaluria

Excess diet sodium

Promotes hypercalciuria

Family history

Genetic predisposition

Insulin resistance

Ammonia mishandling; alters pH of urine

Gout

Promotes hyperuricosuria

Low urine volume

Allows stone constituents come supersaturate

Obesity

May promote hypercalciuria; other results similar to excess dietary meat

Primary hyperparathyroidism

Creates persistent hypercalciuria

Prolonged immobilization

Bone turnover creates hypercalciuria

Renal tubular acidosis (type 1)

Alkaline urine disclosure calcium phosphate supersaturation; ns of citrate


TABLE 1Risk components for the advancement of Urinary CalculiRisk factorMechanisms

Bowel disease

Promotes short urine volume; acidic urine depletes obtainable citrate; hyperoxaluria

Excess dietary meat (including poultry)

Creates acidic urinary milieu, depletes obtainable citrate; promotes hyperuricosuria

Excess diet oxalate

Promotes hyperoxaluria

Excess dietary sodium

Promotes hypercalciuria

Family history

Genetic predisposition

Insulin resistance

Ammonia mishandling; changes pH the urine

Gout

Promotes hyperuricosuria

Low pee volume

Allows stone constituents come supersaturate

Obesity

May encourage hypercalciuria; other results comparable to excess dietary meat

Primary hyperparathyroidism

Creates persistent hypercalciuria

Prolonged immobilization

Bone turnover creates hypercalciuria

Renal tubular acidosis (type 1)

Alkaline urine disclosure calcium phosphate supersaturation; loss of citrate


Calculi are classified into five categories based on their composition: calcium oxalate (70 percent), calcium phosphate (5 come 10 percent), uric mountain (10 percent), struvite (15 to 20 percent) and also cystine (1 percent).3 Calculi deserve to be classified an ext broadly right into calcareous (i.e., calcium-containing) stones and also noncalcareous stones. Calcareous stones usually space visible on radiographic imaging (Figure 1), conversely, noncalcareous stones (i.e., uric acid, cystine, struvite calculi) often are radiolucent or poorly visualized on level film radiography. Numerous calculi have a combined composition, through one type of crystal becoming a nidus for heterogeneous crystallization.


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Figure 1.

Plain film radiograph reflecting a calcium oxalate rock (arrow) in the reduced pole the the ideal kidney.


Figure 1.

Plain film radiograph reflecting a calcium oxalate stone (arrow) in the lower pole that the appropriate kidney.


Most renal calculi do not cause significant symptoms till the stones begin to take trip within the urinary tract. In ~ this point, the pains of acute renal colic is severe and can it is in debilitating. Patients typically describe the pain together crampy and intermittent. It generally originates in the flank and also radiates toward the groin. Because calculus motion is connected with obstruction of a hole viscus, numerous patients endure from linked nausea, v or there is no emesis. Most patients have actually at least microscopic amounts of blood in the urine, and also gross hematuria is possible. Patients through obstructing struvite calculi (i.e., stones associated with urinary infection) may present with fevers, chills, and flank pain. These patients space at risk of progressing to sepsis or death.

Not all patients presenting with f lank pain have actually urinary calculi, so crucial aspect of the initial review is to find for various other potential diagnoses (Table 2). A typical work-up has a thorough background and physics examination, serum chemistry and also complete blood count, urinalysis, and an imaging study. Usual radiographic and laboratory findings are presented in Table 3.


TABLE 2Differential Diagnosis for Urinary CalculiClinical cluesSuggested diagnoses

Anorexia, nausea, vomiting

Obstructing urinary calculi, bowel disease

Dysuria

UTI, urinary calculi, interstitial cystitis

Fever, chills

Viral or bacter illness

Hematuria (microscopic or gross)

Urinary calculi, urothelial tumor, UTI, BPH, renal mass

Hemodynamic instability

Nonspecific result of shock (including possible sepsis)

Inability to acquire comfortable

Urinary calculi, peritonitis

Pain and tenderness

Abdominal pain

Small renal calculi, nonurologic etiology (gastrointestinal origin)

Flank pains (sharp, extreme pain through sudden onset)

Urinary calculi, musculoskeletal spasm

Flank tenderness

Urinary calculi, musculoskeletal inflammation, pyelonephritis

Groin pain (scrotal, labial)

Ureteral calculi, hernia, testicular mass

Penile or pelvic pain

Ureteral calculi, urethritis, prostatitis

Suprapubic tenderness

UTI, interstitial cystitis, prostatitis, urinary calculi, peritonitis

Tachycardia

Nonspecific an answer to pain

Urinary frequency

UTI, ureteral calculi, BPH


TABLE 2Differential Diagnosis for Urinary CalculiClinical cluesSuggested diagnoses

Anorexia, nausea, vomiting

Obstructing urinary calculi, bowel disease

Dysuria

UTI, urinary calculi, interstitial cystitis

Fever, chills

Viral or bacterial illness

Hematuria (microscopic or gross)

Urinary calculi, urothelial tumor, UTI, BPH, renal mass

Hemodynamic instability

Nonspecific findings of shock (including possible sepsis)

Inability to gain comfortable

Urinary calculi, peritonitis

Pain and also tenderness

Abdominal pain

Small renal calculi, nonurologic etiology (gastrointestinal origin)

Flank pains (sharp, too much pain with sudden onset)

Urinary calculi, musculoskeletal spasm

Flank tenderness

Urinary calculi, musculoskeletal inflammation, pyelonephritis

Groin pains (scrotal, labial)

Ureteral calculi, hernia, testicular mass

Penile or pelvic pain

Ureteral calculi, urethritis, prostatitis

Suprapubic tenderness

UTI, interstitial cystitis, prostatitis, urinary calculi, peritonitis

Tachycardia

Nonspecific an answer to pain

Urinary frequency

UTI, ureteral calculi, BPH


TABLE 3Clinical ideas to the Diagnosis the Urinary CalculiEvaluationPossible findings

Laboratory evaluations

Complete blood count

Leukocytosis with struvite calculi

Serum chemistry

Elevation in creatinine levels through obstructing calculi; hypokalemia and hyperchloremia v renal tubular acidosis; elevated serum calcium levels v parathyroid disease

Serum parathyroid hormone levels

Elevated in hyperparathyroidism

Urinalysis

Microscopic or pistol hematuria; acidic urine; alkaline urine (with struvite calculi); pyuria; crystals from connected calculi

24-hour urinalysis

Elevated urinary calcium, oxalate, and also sodium levels; lessened urinary volume and also citrate levels

Radiographic evaluations

Abdominal, kidney, and also upper bladder radiography

Urinary calculi bigger than 2 mm might be visible.

CT (stone protocol)

Nearly every calculi space visible top top CT. Evaluates renal parenchyma, hydronephrotic changes, and surrounding guts for various other etiologies of ab pain.

Intravenous pyelography

Calculi clearly shows on scout film. Delay in comparison excretion if obstruction is present. Calculi may appear as filling defect.

MRI

Conventional MRI is not valuable for imaging calculi.

Ultrasonography

Calculi show up as hyperechoic lesions that cast acoustic shadows. Not trusted for ureteral calculi. May show dilation that collecting system.


TABLE 3Clinical ideas to the Diagnosis of Urinary CalculiEvaluationPossible findings

Laboratory evaluations

Complete blood count

Leukocytosis with struvite calculi

Serum chemistry

Elevation in creatinine levels through obstructing calculi; hypokalemia and also hyperchloremia through renal tubular acidosis; elevated serum calcium levels through parathyroid disease

Serum parathyroid hormone levels

Elevated in hyperparathyroidism

Urinalysis

Microscopic or gun hematuria; acidic urine; alkaline urine (with struvite calculi); pyuria; crystals from affiliated calculi

24-hour urinalysis

Elevated urinary calcium, oxalate, and sodium levels; reduced urinary volume and citrate levels

Radiographic evaluations

Abdominal, kidney, and upper bladder radiography

Urinary calculi larger than 2 mm may be visible.

CT (stone protocol)

Nearly all calculi are visible on CT. Evaluates renal parenchyma, hydronephrotic changes, and surrounding organs for other etiologies of abdominal pain.

Intravenous pyelography

Calculi clearly shows on scout film. Hold-up in contrast excretion if obstruction is present. Calculi may show up as filling defect.

MRI

Conventional MRI is not beneficial for imaging calculi.

Ultrasonography

Calculi show up as hyperechoic lesions that cast acoustic shadows. Not reliable for ureteral calculi. May show dilation that collecting system.


Most calculi room visible on level film radiography, but noncontrast computed tomography (CT) has end up being the imaging modality of selection because that its capability to visualize stones of any kind of composition (Figure 2), its ability to identify unexpected concomitant pathology, and also the absence of intravenous contrast media.5,6 rock size deserve to be measure from many imaging modalities, offering prognostic information.


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Figure 2.

Computed tomography scan mirroring a calculus in the appropriate kidney.


Figure 2.

Computed tomography scan mirroring a calculus in the right kidney.


With hydration and also pain control, calculi smaller sized than 5 mm will pass spontaneously in around 90 percent the patients. The rates of i decrease as rock size increases; a 1-cm rock has a less than 10 percent opportunity of passing without surgical intervention.7 recent studies8 have suggested that the usage of the alpha1-adrenergic blocker tamsulosin (Flomax) deserve to increase the opportunity of spontaneous passage of ureteral stones. However, immediate surgical intervention with a ureteral stent or percutaneous nephrostomy is important if the patient exhibits signs and also symptoms that obstruction and sepsis. Clinically secure patients commonly are provided the option of attempting to happen the stone spontaneously if the is not too large and if the pains is manageable with oral narcotics. Surgical options include extracorporeal shock tide lithotripsy, ureteroscopic stone extraction, and percutaneous nephrolithotomy.


After the initial rock episode has resolved, patients should be counseled about prevention that recurrences. A simple evaluation should encompass a thoroughly history, including period at onset, frequency and number of previous calculi, and also any previous medical or surgical interventions. Added information should incorporate an testimonial of fluid and also dietary habits and a background of predisposing conditions such as bowel disease, gout, and a family history of urinary calculi. Serum research studies should incorporate electrolyte, calcium, phosphate, uric acid, and also intact parathyroid hormone levels.

A much more thorough evaluation has been promoted for patient who have had much more than one rock episode. In this patients, the price of added laboratory tests and pharmacotherapy most likely is much less than the price of repeat emergency room visits and also surgical management.9,10 An increased evaluation consists of two 24-hour urine collections to identify urine volume, pH, and calcium, creatinine, sodium, phosphate, oxalate, citrate, uric acid, and also cystine levels. Crystallographic analysis of recall calculus remnants can aid identify the underlying etiology and may obviate a finish metabolic evaluation.

Medical prophylaxis the recurrent urinary calculi consists of generalized references and specific directed therapy when suitable (Figure 3). As noted previously, patients through recurrent episodes warrant a more aggressive approach.


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Medical administration of Nephrolithiasis

Figure 3.

Algorithm because that the medical monitoring of recurrent urinary calculi.


Medical management of Nephrolithiasis

Figure 3.

Algorithm because that the medical monitoring of recurrent urinary calculi.


GENERAL RECOMMENDATIONS

Evidence native one prospective trial11 shows that raised water intake reduces the risk of recurrence of urinary calculi and also prolongs the average interval between recurrences. A target the 2.1 qt (2 L) of urine manufacturing per day typically is recommended.12 One prospective study13 showed that a low-salt, low-meat, moderate-calcium diet is an ext effective in ~ limiting stone recurrence 보다 a low-calcium diet. The presence of calcium in the gut helps bind oxalate from foods, in order to limiting the absorb of oxalate in the big intestine. Avoidance of huge quantities that high–oxalate-containing foods items is recommended. Excessive weight is an live independence risk aspect for urinary calculi, specifically in women.14,15 weight loss is desirable in this patients.

CALCIUM OXALATE CALCULI

Calcium oxalate stones space the most common kind of urinary calculi and can exist in monohydrate and also dihydrate forms, v or without phosphate. High phosphate content may be connected with greater recurrence rates.16 Calcium oxalate stones room radiopaque and also usually clearly shows on level film radiography or noncontrast CT.

The causes of calcium oxalate stones and their mechanisms are listed in Table 4. Hypercalciuria (i.e., much more than 250 mg every 24 hrs <6.2 mmol every day>) is the most usual metabolic abnormality associated with these calculi, complied with by hypocitraturia (i.e., much less than 450 mg every 24 hours <2.34 mmol per day>), which entails a deficiency the the naturally occurring rock inhibitor citrate. The cause of hypocitraturia regularly is idiopathic, return high dietary acid tons (e.g., from excessive meat intake) and dehydration have the right to exacerbate this condition. Other reasons of calcium oxalate stones incorporate hyperoxaluria (i.e., an ext than 45 mg every 24 hrs <500 μmol per day>) and also hyperuricosuria (i.e., more than 800 mg per 24 hours <4.76 mmol per day>). Treatments for these stones rely on the underlying condition (Table 4). Note that there room no particular medications for hyperoxaluria; medical treatment is composed of enhancing calcium entry (particularly v meals) to regulate enteric hyperoxaluria. Additionally, decreasing the input of oxalates contained in foods items such together spinach, rhubarb, beets, chocolate, nuts, tea, strawberries, soybean beans foods, and wheat bran may be beneficial.17 Calcium oxalate calculi not associated with an obvious laboratory abnormality can be treated empirically with oral potassium citrate (Urocit-K, 30 to 60 mEq every day) or sodium citrate (Bicitra) to increase urine pH and levels of urinary citrate.18,19


TABLE 4Common causes of Calcium Oxalate CalculiAbnormalityPossible mechanismTreatments

Hypercalciuria (more than 250 mg per 24 hours <6.2 mmol per day>)

Absorptive hypercalciuria

Increased minister absorption of calcium

Thiazide diuretic*, potassium citrate (Urocit-K)†

Idiopathic hypercalciuria

Inherited trait

Thiazide diuretic*, potassium citrate†

Primary hyperparathyroidism

Increased bone demineralization or increased intestinal calcium absorption

Parathyroidectomy

Renal hypercalciuria

Renal leak the calcium

Thiazide diuretic*, potassium citrate†

Hyperoxaluria (more than 45 mg per 24 hours <500 μmol per day>)

Enteric hyperoxaluria

Malabsorption from any cause with increased urinary oxalate to facility with calcium

Decrease oxalate intake, boost calcium intake

Primary hyperoxaluria

Metabolic error with high level the oxalate production and also urinary excretion

Decrease oxalate intake, boost calcium intake

Hyperuricosuria (more than 800 mg every 24 hrs <4.76 mmol per day>)

Increased uric acid promotes calcium oxalate crystallization via the development of nuclei

Potassium citrate†, allopurinol (Zyloprim; 100 to 300 mg daily, provided orally)

Hypocitraturia (less than 450 mg every 24 hrs <2.34 mmol per day>)

Idiopathic; renal tubular acidosis (types 1, 2, and also 4)

Potassium citrate†


*—Common thiazide diuretics encompass hydrochlorothiazide (Esidrix; 25 mg twice daily, given orally) and also chlorthalidone (Hygroton; 50 mg daily, given orally).


† —Dosage for potassium citrate is 10 to 20 mEq twice or three times day-to-day with meals, given orally.


TABLE 4Common causes of Calcium Oxalate CalculiAbnormalityPossible mechanismTreatments

Hypercalciuria (more 보다 250 mg per 24 hours <6.2 mmol every day>)

Absorptive hypercalciuria

Increased intestinal absorption that calcium

Thiazide diuretic*, potassium citrate (Urocit-K)†

Idiopathic hypercalciuria

Inherited trait

Thiazide diuretic*, potassium citrate†

Primary hyperparathyroidism

Increased bone demineralization or boosted intestinal calcium absorption

Parathyroidectomy

Renal hypercalciuria

Renal leak the calcium

Thiazide diuretic*, potassium citrate†

Hyperoxaluria (more 보다 45 mg every 24 hours <500 μmol every day>)

Enteric hyperoxaluria

Malabsorption from any type of cause with increased urinary oxalate to complicated with calcium

Decrease oxalate intake, rise calcium intake

Primary hyperoxaluria

Metabolic error through high level of oxalate production and urinary excretion

Decrease oxalate intake, increase calcium intake

Hyperuricosuria (more 보다 800 mg per 24 hours <4.76 mmol per day>)

Increased uric acid promotes calcium oxalate crystallization via the formation of nuclei

Potassium citrate†, allopurinol (Zyloprim; 100 to 300 mg daily, provided orally)

Hypocitraturia (less 보다 450 mg every 24 hrs <2.34 mmol per day>)

Idiopathic; renal tubular acidosis (types 1, 2, and also 4)

Potassium citrate†


*—Common thiazide diuretics encompass hydrochlorothiazide (Esidrix; 25 mg double daily, provided orally) and chlorthalidone (Hygroton; 50 mg daily, provided orally).


† —Dosage for potassium citrate is 10 come 20 mEq double or three times everyday with meals, offered orally.


CALCIUM PHOSPHATE CALCULI

Calculi that consist mostly of calcium phosphate occur an ext often in females than in men. They regularly are connected with acidification disorders such as renal tubular acidosis20; less usual etiologies include primary hyperparathyroidism, too much alkalinization, and sarcoidosis. Renal tubular acidosis is connected with hypercalciuria and also hypocitraturia. Clinical treatment of this stones is composed of replenishing urinary citrate come prevent brand-new stone formation and delay growth of existing stones. Care must be required to avoid extreme alkalinization, since high urinary pH deserve to increase the urinary supersaturation of calcium phosphate salts. If hypercalciuria persists, addition of a thiazide diuretic is indicated.21

URIC mountain CALCULI

Uric acid stones might consist that uric mountain only, or they likewise may contain calcium.22 Uric acid is a by-product of ingested or endogenous purine metabolism and also is excreted in the urine mostly in insoluble form. The primary cause of uric acid stones is a urinary pH below the pKa for uric mountain (5.5). Various other predisposing problems include gout, insulin-resistant states, and also end-ileostomies. Men with gout have a twofold hazard of having a uric mountain calculus.23 In general, this patients excrete too much uric acid (although some have normouricosuria) and also have short urinary pH and also urine volumes. Overfill ingestion of pet meat protein (i.e., meat of all types, consisting of poultry) deserve to be detected by measuring urinary sulfate levels. Radiographic imaging can be complicated because pure uric acid calculi generally are radiolucent. They are, however, readily noticeable on noncontrast CT. In enhancement to the basic measures outlined above, treatment of uric acid stones entails correction the urinary pH. Potassium citrate at a dosage that 30 to 60 mEq per day will raise the urinary pH to higher than 5.5 (6.5 to 7 is ideal).24 Allopurinol (Zyloprim) at a dosage of 300 mg everyday can be added in patients v hyperuricemia.

STRUVITE CALCULI

Struvite stones, likewise known as infection or triple-phosphate stones, covers magnesium, ammonium, and calcium phosphate. They occur more often in ladies than in men and also are the leading cause of staghorn calculi (Figure 4). Neurogenic bladders and also foreign body in the urinary tract additionally predispose patients to struvite calculi. Recurrent urinary tract infections v urea-splitting biology (e.g., Proteus mirabilis, Urea-plasma urealyticum, Klebsiella pneumoniae) an outcome in alkalinization of urine and the addition of ammonium to the milieu.25 Struvite stones are usually radiopaque on conventional radiographic imaging yet may be fairly faint. Patients with struvite calculi may existing with flank pain and also may have actually signs of systemic infection.


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Figure 4.

Radiograph the the left kidney and also upper bladder mirroring a finish staghorn calculus.


Figure 4.

Radiograph the the left kidney and also upper bladder reflecting a complete staghorn calculus.


There is an excellent evidence that failure to treat struvite stones have the right to lead come an enhanced risk that renal loss, sepsis, and death.26,27 However, if the patient is febrile or presents with indicators of systemic infection, operation manipulation need to be delayed until antibiotic treatment has been administered and also the patient has actually been afebrile because that at least 48 hours. After operation intervention, clinical therapy should emphasis on staying clear of recurrent urinary street infections. Retained residual fragments increase the risk of recurrent urinary tract infection and also future calculi. Acetohydroxamic acid (Lithostat) is an irreversible inhibitor of urease and also can avoid the crystallization the struvite stones.28 However, since of side impacts (including deep venous thrombosis), it generally is reserved for use in patients who cannot tolerate operation intervention.29

CYSTINE CALCULI

Patients with cystine calculi have an autosomal recessive disorder of dibasic amino acid carry leading to lessened cystine resorption in the kidney. Just homozygote patients form cystine calculi and also often present with stones throughout childhood. Calculi may be pure cystine or may be mixed with calcium oxalate. Cystine is poorly soluble at regular urinary pH and also will readily type stones once levels rise over a concentration that 250 mg every L. Pure cystine stones space yellow and radiolucent or faintly radiopaque (Figure 5). A urinary cystine level of more than 250 mg every 24 hours (1,040 μmol per day) is diagnostic because that the disorder


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Figure 5.

Radiograph showing a faintly radiopaque cystine calculus (arrow) overlying the 12th rib in the left kidney of a 13-year-old girl.


Figure 5.

Radiograph reflecting a faintly radiopaque cystine calculus (arrow) overlying the 12th rib in the left kidney that a 13-year-old girl.

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Dietary manipulation with a low-methionine diet is challenging and hardly ever successful. Hydration and management of urinary alkalinizing agents such as potassium citrate room mainstays that therapy. However, it regularly is an overwhelming to achieve adequate alkalinization with oral agents. If these steps are no effective, management of cystine binder such together penicillamine (Cuprimine) and also tiopronin (Thiola) can help prevent cystine calculi. Although this agents room effective, they have the right to cause significant side impacts such as gastrointestinal distress, rheumatologic symptoms, psychological status changes, and skin rashes.30


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