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Urinary stone disease is a multifactorial disorder that is influenced by both intrinsic and environmental factors. Diet, climate, genetics, and metabolic processes may be involved in stone formation. Hormonal influences on stone disease have long been acknowledged and include disorders of calcium homeostasis, sex-related differences, and imbalances of other hormones that play a secondary role in calcium balance. Although the pathophysiologic mechanisms of some disorders, such as hyperparathyroidism, have been elucidated, the actions of other hormones on urolithiasis remain elusive.

Stone diseases have had known affinities to other systemic diseases for a large portion of written medical history. The first known stone to afflict a human was probably a metabolic product of uric acid metabolism in a boy of the predynastic Egyptian period, almost 7000 years ago. Galen (131–201 ad) proposed the concept that etiologic aspects of stone formation include heredity, climatic, and nutritional factors. Van Helmont (1577–1644) noted that kidney stones were products of undesirable minerals within the urine. Thomas Sydenham (1624–1689) suffered from gout and recurrent urolithiasis. He describes his own disease process with clarity and proposed three hypotheses for the pathophysiology of stone disease and other systemic illnesses. On his disquisition into gout he states: “”(1).

Medical management entails identification of causes of stone formation based largely on detection of abnormal urinary biochemistry (risk factors) , and application of dietary modification and pharmacological treatment designed to correct underlying disturbances The importance of medical management is based on two important findings. Urolithiasis is characterized by a high recurrence rate . It is estimated that approx 60–80% of patients will form another stone within 10 yr of the first episode. Removal of existing stone does not prevent further stone formation .

The management of nephrolithiasis forms an important part of urologic practice. The recurrence rate after forming an initial stone is reported to be as high as 50% at 5 yr and 80–90% at 10 yr, highlighting the importance of medical prophylactic therapy. A better understanding of pathophysiology and formulation of diagnostic criteria for different etiologies of nephrolithiathis have made feasible the adoption of selective treatment programs. the objectives of medical stone management should be:

Nephrolithiasis is a common disorder affecting approx 8–13% of the US population . After experiencing renal colic and/or treatment for urinary stones, nearly every patient expresses interest in diet and specific dietary changes useful in lowering the risk for future stones.

Uric acid calculi are responsible for 5–10% of calculi in the North American population. These radiolucent stones are of particular interest because of their ability to be successfully managed with both medical therapy and surgical intervention. The pathophysiology is unique and important to understand when treatment is being planned.

The occurrence of urinary infection in patients with nephrolithiasis is not uncommon. Although stones of any composition may occur in patients who experience urinary tract infections owing to a variety of urinary pathogens, the term“infection stone” is reserved for calculi that form as a direct consequence of infection with urease-producing bacteria and the urinary environment they promote. This chapter will focus on current concepts regarding infection stones, including their pathogenesis, clinical diagnosis and treatment.

Cystinuria is an autosomal recessive disease characterized by defects in renal and intestinal transport of dibasic amino acids including cystine, ornithine, lysine, and arginine . The relative insolubility of cystine results in supersaturation of urine with cystine and recurrent stone formation, which is the hallmark of the disease.

The vast majority of urinary stones are composed of calcium oxalate, calcium phosphate, struvite, uric acid, or cystine. Enumerable studies analyzing over 45,000 total calculi have shown urinary stones to be composed of“other” constituents only 0.5-3.5% of the time. Although uncommon, these stones can be challenging to both diagnose and to treat. In many cases, accurate diagnosis is necessary for proper treatment. This challenge begins with routine stone analysis, especially in the case of radiolucent stones that do not clinically fit the uric acid picture, or that recur despite appropriate therapy with strict urinary alkalinization and xanthine oxidase inhibition.

Acute flank pain, with or without hematuria, is a common complaint and urolithiasis is the primary consideration in many of these patients. Clinical findings are often nonspecific and may overlap other conditions. Imaging plays an important role in both diagnosis and subsequent management of urinary stone disease. Radiological imaging of urinary stones dates back to 1897, the year after Roentgen’ s discovery of X-rays. Early attempts at opacification of the urinary tract included retrograde placement of ureteral intraluminal wires and opaque catheters, air, colloidal silver, and sodium iodide (1). Iodinated contrast agents that were excreted by the kidneys and could be administered intravenously were developed in the 1920s. For the next 70 yr, intravenous pyelography or excretory urography, including a preliminary noncontrast scout view, was the primary modality for imaging urinary stones. Computed tomography (CT) was introduced in the mid-1970s. Early CT scanners could sometimes visualize urinary calculi, but CT was not a reliable method to confidently exclude stones because these slower nonhelical scanners were plagued by misregistration between sequential images. Stones present in these nonvisualized gaps could escape detection. If seen, stone size was frequently underestimated if only the top or bottom edge of the stone was included in the slice. For these reasons, nonhelical CT was unsuitable for the primary work-up of suspected urolithiasis. The introduction of helical CT scanners in the early 1990s revolutionized the imaging of urinary stone disease. With these more rapid helical CT scanners, large anatomic regions could be scanned during a single breath hold with thin slices and no misregistration. Multislice helical scanners, introduced in the late 1990s, led to the ability to obtain even thinner slices in less time, allowing the detection of smaller, less dense calculi and reducing the likelihood of false-negative scans. In most centers, nonenhanced CT has replaced the intravenous urography (IVU) as the modality of choice for the imaging of urinary stones.