Stone formation

Nucleic acid contents of SCP products, which range up to 16% in bacteria and 6—11% in yeasts, must be reduced by processing so that intakes are less than 2 g/d to prevent kidney stone formation or gout. Adverse skin and gastrointestinal reactions have also been encountered as a result of human consumption of some SCP products (87). 

Maintaining Adequate Fluid Intake and Output Because one adverse reaction of the sulfonamide dragp is altered elimination patterns, it is important that the nurse helps the patient maintain adequate fluid intake and output. The nurse can encourage patients to increase fluid intake to 2000 mL or more a day to prevent crystal-luria and stone formation in the genitourinary tract, as well as to aid in the removal of microorganisms from the urinary tract. It is important to measure and record the intake and output every 8 hours and notify the primary health care provider if the urinary output decreases or the patient fails to increase his or her oral intake... 

DRUGS USED FOR GOUT. The nurse encourages a liberal fluid intake and measures the intake and output. The daily urine output should be at least 2 liters. An increase in urinary output is necessary to excrete the urates (uric acid) and prevent urate acid stone formation in the genitourinary tract. 

Although generally well tolerated, probenecid can cause gastrointestinal side effects such as nausea and other adverse reactions, including fever, rash, and rarely, hepatic toxicity. Patients should be instructed to maintain an adequate fluid intake and urine output to decrease the risk of uric acid stone formation. Some experts advocate alkalinizing the urine to decrease this risk. 

Cystinuria. Penicillamine reduces excess cystine excretion in cystinuria. Penicillamine with conventional therapy decreases crystalluria and stone formation, and may decrease the size of or dissolving existing stones. This is achieved by disulfide interchange between penicillamine and cystine, resulting in a substance more soluble than cystine and readily excreted. 

The major side effects associated with uricosuric therapy are GI irritation, rash and hypersensitivity, precipitation of acute gouty arthritis, and stone formation. These drugs are contraindicated in patients who are allergic to them and in patients with impaired renal function (CLcr <50 mL/min) or a history of renal calculi, and in patients who are overproducers of uric acid. 

K. Nakai, S. Tazuma, T. Nishioka and K. Chayama, Inhibition of cholesterol crystallization under bilirubi deconjugation partial characterization of mechanism whereby infected bile accelerates pigment stone formation. Biochem. Biophys. Acta 1632 (2003) 48-54. 

Table 8.2 summarises some of the conditions in which there is impaired gallbladder motor function and an associated increase in the prevalence of either sludge (which may pre-dispose to stone formation), frank gallstones or both. The role of Octreotide (OT) will now be focused upon since this illustrates the whole sequence of pathogenic changes found in conventional GBS disease -albeit eclipsed into weeks or months. 

S.L. Anna, N. Bontoux, and FI.A. Stone Formation of Dispersions Using Flow Focusing in Microchannels. Appl. Phys. Lett. 82, 364 (2003). 

The altered composition of bile increases the capacity for cholesterol uptake. Thus, gallstones can be dissolved in the course of a 1- to 2 y treatment, provided that cholesterol stones are pure and not too large (<15 mm), gall bladder function is normal, liver disease is absent, and patients are of normal body weight. UCDA is more effective (daily dose, 8-10 mg) and better tolerated than is CDCA (15 mg/d frequent diarrhea, elevation of liver enzymes in plasma). Stone formation may recur after cessation of successful therapy. 

Renal stones Triamterene has been found in renal stones with other usual calculus components. Use cautiously in patients with histories of stone formation. Hematologic effects Triamterene is a weak folic acid antagonist. Because cirrhotics with splenomegaly may have marked variations in hematological status, it may contribute to the appearance of megaloblastosis in cases where folic acid stores have been depleted. Perform periodic blood studies in these patients. 

Increased fluid intake increases urinary output, lowering substance concentration involved in stone formation. Hydration is recommended to reduce new stone formation. 

Fluid intake Adequate fluid intake must be maintained in order to prevent crystalluria and stone formation. 

Renal/Hepatic function impairment Use with caution. Maintain adequate fluid intake to prevent crystalluria and stone formation. Patients with severely impaired renal function exhibit an increase in the half-lives of both TMP and SMZ, requiring dosage regimen adjustment. 

The presence of Ca in kidney stones and the abnormally high Ca levels in idiopathic (absorptive) hypercalciuric individuals that are inherently more prone to kidney stones, initially led to the belief that dietary Ca may be a cause of renal stone formation (Coe et al., 1992). Recent evidence suggests that, as a therapeutic approach to reducing the risk for kidney stones, Ca-restricted diets may pose a greater risk to normocalciuric individuals prone to kidney stone formation such an approach may increase urinary oxalate and the likelihood of recurrent stones, as well as promote bone loss (Borghi et ah, 2002 Coe et al., 1997 Curhan et ah, 1997). The amoimt of oxalate excreted in urine has been foimd to be positively associated with Ca oxalate supersaturation and stone formation (Holmes et ah, 2001). While free oxalic acid is readily absorbed from the gut lumen (Morozumi et ah, 2006), an increased dietary Ca to oxalate... 

Two renal responses are unique to the thiazide and thiazidehke diuretics. With these compounds, Na+ excretion is increased, while Ca++ excretion is decreased, primarily and directly because of increased distal Ca++ reabsorption, secondarily and indirectly because of a compensatory elevation of proximal solute absorption, making this class of diuretics useful in treating hypercal-ciuria. This effect, which may not be evident upon initial administration of the drug, is particularly benehcial in individuals who are prone to calcium stone formation. 

Hyperoxaluria and hypomagnesiuria, which negate the beneficial effect of hypo-calciuria on new stone formation, magnesium depletion, and depletion of trace metals (copper, zinc, iron) may occur. 

Drink plenty of fluids to prevent kidney stone formation... 

Calcium and magnesium homeostasis is altered by chronic diuretic therapy. Loop diuretics increase the urinary excretion of Ca2+ and can lead to stone formation. Thiazide administration, on the other hand, has the opposite effect and causes frank hypercalcaemia in some patients. Both thiazide and loop drugs increase the urinary loss of Mg2+ and this has been associated with cardiac arrythmias in the elderly. 

Phosphaturia and hypercalciuria occur during the bicarbonaturic response to inhibitors of carbonic anhydrase. Renal excretion of solubilizing factors (eg, citrate) may also decline with chronic use. Calcium salts are relatively insoluble at alkaline pH, which means that the potential for renal stone formation from these salts is enhanced. 

It is essential to maintain a large urine volume to minimize the possibility of stone formation. 

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