NEPHROLITHIASIS

NEPHROLITHIASIS
Nephrolithiasis is another name for kidney stones. Kidney stones are also called renal calculi. These are rock-like pieces that are about the size of a grain of sand. They form most often in the kidneys and get stuck in the ureter. It is caused when water and waste crystals in the urine are out of balance. They can form when the urine contains too much of certain substances namely uric acid, calcium, or phosphate which eventually separate from the urine. Instead of going out of the body in the urine, the crystals build up. These small crystals later become stones and block the flow of urine and cause pain. A person with such condition may have more than one stone.
Kidney stones may not produce symptoms until they begin to move down the ureter, causing pain. Pain is its most common sign which basically comes on suddenly. It may come and go and is usually severe and often starts in the flank region, then moves down to the groin. Blood in the urine may also be seen, which will look pink or red accompanying difficult and painful urination. Other manifestations include feeling sick to the stomach (nausea) and throwing up (vomiting). Fever and chills may also be present once the stones have already caused an infection.
Oftentimes, nephrolithiasis can be treated at home and the stone will pass on its own. If the stone does not pass, then hospitalization may be sought and it may need to have surgery to remove it. Among the surgical procedures used in the removal of kidney stones were Ureteroscopy, Percutaneous Nephrostolithotomy, Ureteroscopic Stone Removal and Open Surgery. Or in some cases, lithotripsy (a medical procedure that uses shock waves to break up stones that form in the kidney, bladder, ureters, or gallbladder) may be performed to break it apart. Urine and probably, blood will then need to be tested. Other diagnostic tests may include x-ray, called an IVP (Intravenous Pyelogram), and ultrasound to look for the stone.
Men get kidney stones more often than women. Kidney stones occur mostly in people 20 to 60 years old. But they can happen to anyone at any age.
The prevalence of nephrolithiasis varies according to its form as determined by the waste crystal that has precipitated such condition. Calcium stone disease is the most common form of nephrolithiasis and represents about 70% of all stone-forming disease. It occurs most often in the third to fifth decade of life, more often in men than women. Uric acid stone disease is found in about 5% to 10% of stone formers. It is more common in patients with chronic diarrheal disorders and in those with hyperuricosuria (excretion of excessive amounts of uric acid in the urine). Infection stones, also known as struvite or magnesium ammonium phosphate stones occur in about 10% to 12% of patients, more often in women. They occur more often also in patients with spinal cord injury, neurogenic bladder, vesicoureteral reflux, chronic indwelling Foley catheters, and recurrent urinary infections, and in those with chronic obstruction of the upper urinary tracts.
The overall probability of forming stones differs in various parts of the world: 1-5% in Asia, 5-9% in Europe, 13% in North America, 20% in Saudi Arabia. The composition of stones and their location in the urinary tract, bladder or kidneys may also significantly differ in different countries. Moreover, in the same region, the clinical and metabolic patterns of stone disease can change over time. Some epidemiological evidence about the main risk factors for stone formation, both individual and environmental has been examined. And it has been found out that a slightly higher rate of renal stone disease emerged in males than in females, and in white Caucasians than in Blacks. Stones in the upper urinary tract appear to be related to the lifestyle, being more frequent among affluent people, living in developed countries, with high animal protein consumption. Bladder stones are nowadays mainly seen in the Third World, on account of very poor socio-economic conditions. A high frequency of stone formation among hypertensive patients has been reported, and among those with high body mass as well. There is no evidence of any rise in the risk of stone formation in relation to dietary calcium intake.
Older data estimated that 12 percent of men and 5 percent of women will have at least one symptomatic stone by the age of 70; over 80 percent of these stones will contain calcium, usually as calcium oxalate. The prevalence of kidney stones, however, appears to be increasing in the United States. In a report from the Third National Health and Nutritional Examination Survey, the prevalence increased from 3.8 to 5.2 percent in the period 1976 to 1980 compared with 1988 to 1994, respectively. Furthermore, the male to female ratio has changed over the past 25 years, from 3:1 (male:female) to now less than 2:1. Whether this represents an actual increase in incidence or an increase in detection is uncertain.
The prevalence of nephrolithiasis varies regionally. In one study of over 40,000 men between the ages of 45 and 70, the risk of having a history of kidney stones was 13 and 31 percent lower in the mid-Atlantic and northwestern regions compared to the southeastern United States. A second study confirmed this regional variation, but found that differences were greatly reduced after adjustment for temperature, sunlight, and beverage consumption.
The rate of nephrolithiasis increases with age, is slightly higher in men compared to women, and in whites compared to blacks. Hispanics and Asians are at intermediate risk. It has been estimated that 7 to 10 of every 1,000 hospital admissions are due to stones.


Nephrolithiasis Treatment and Management
Treatment should consist of high fluid intake and dietary sodium restriction. Remaining well-hydrated and keeping the urine dilute will help prevent kidney stones from forming.
Besides advising patients to avoid excessive salt and protein intake and to increase fluid intake, base medical therapy for the chronic chemoprophylaxis of urinary calculi on the results of a 24-hour urinalysis for chemical constituents.
Dietary calcium restriction is not advised because of the potential for negative calcium balance and because a low calcium diet increases gastrointestinal absorption of oxalate and increased oxaluria (presence of oxalic acid in the urine).
Since the solubility of uric acid is greatly increased when urine pH is raised, treatment should consist of alkalinization of urine to pH >6.5 with potassium citrate solution, 30 to 90 mEq per day in divided doses, and by hydration. This treatment has been shown to reduce uric acid stones by 90%. Such treatment, given to a patient with small stones in the kidneys, may also result in dissolution of the stones.
Uric acid and cystine calculi can be dissolved with medical therapy. Patients with uric acid stones who do not require urgent surgical intervention for reasons of pain, obstruction, or infection can often have their stones dissolved with alkalinization of the urine.
Alkalinization of the urine with sodium bicarbonate or sodium citrate is not recommended because the sodium salts will increase calcium excretion and increase the tendency to form calcium oxalate stones.
Therapy must eradicate the urinary infection. Since the stones themselves are frequently infected with bacteria, the urinary infection cannot be eradicated without removing the stones as well. Thus, surgical removal of the stones accompanied by appropriate antibiotic therapy is necessary.
Obstruction in the absence of infection can be initially managed with analgesics and with other medical measures to facilitate passage of the stone. Infection in the absence of obstruction can be initially managed with antimicrobial therapy.
If both obstruction and infection are present, emergent decompression of the upper urinary collecting system is required.
Ibuprofen can be used as an anti-inflammatory agent, and if further pain medication is needed, contacting the primary care provider may allow stronger narcotic pain medication to be prescribed.
The calcium channel blocker nifedipine relaxes ureteral smooth muscle and enhances stone passage.
Urinary calculi composed predominantly of calcium cannot be dissolved with current medical therapy; however, medical therapy is important in the long-term chemoprophylaxis of further calculus growth or formation.