Monday , 17 June 2024

An Overview on urolithiasis

K. Siva*, M.V. Sai lalith Kumar, Y. Sarath, M.Lavanya
Narayana Pharmacy College, chintareddypalem, Nellore, Andhrapradesh, India.
E-mail[email protected]

Urolithiasis is the process of forming stones in the kidney, bladder, and/or urethra (urinary tract).In urinary stasis the minerals dissolved in the urine begin to settle out when the urine is static (not moving), forming crystals. The formed crystals attract more of their composite minerals, eventually hardening into calculi. Small stones often easily pass through the urethra in the urine without the person’s awareness of them. Stones that are large enough to scrape the walls of the urethra, or sand like clumps of calculi that surge through the urethra, may cause irritation such as Dysuria (burning sensation) with urination. Other symptoms may include Urinary frequency, Urinary urgency, and urinary hesitation (difficulty starting urination, or start-and-stop urination). Though the mechanism of urinary calculus formation remains imperfectly understood, a number of contributing factors have been clearly established as important. Some of these factors can be simply demonstrated in experiments using rats with a surgically inserted foreign body in the bladder. The foreign body serves as a uniform stimulus to stone formation, for such rats, even though maintained on a normal diet, consistently form a stone about the foreign body. In controlled experiments, if one or another of the supposed etiologic factors is removed, its significance becomes manifest in any difference in the weight of stone produced.
Key words: Urolithiasis, Calculi, Dysuria, Urinary Hesitation, Urinary Urgency
Urolithiasis is the condition where urinary calculi are formed or located anywhere in the urinary system or the process of forming stones in the kidney, bladder, and ureters. Urolithiasis (UL) is one of the most common diseases, with approximately 750 000 cases per year in Germany. Although most patients have only one stone episode, 25% of patients experience recurrent stone formation. This paper reviews trends in epidemiology and current concepts regarding the pathogenesis and pathophysiology of urinary stone disease.
Pathogenesis and pathophysiology:
The development of stones is related to:
Decreased urine volume
Increased excretion of stone-forming components
Inadequate urine drainage, which may lead to statis
Decrease in urinary citrate levels leading to ca+2 deposition
Urinary stone formation is a result of different mechanisms where as exceeding super saturation (i.e., free stone formation) is the cause of uric acid or cystine calculi, infection stones result from bacterial metabolism . The formation of the most common fraction, the calcium-containing calculi, is more complex and, surprisingly, is not yet completely understood. Recent evidence suggests that both free and fixed stone formation is possible. The long accepted simple explanation of exceeding the solubility product of lithogenic substances in the urine cannot describe these complex processes sufficiently. Deviating from the hypothesis that claims the initial crystal deposition takes place in the lumens of renal tubules , new insights suggest a primary plaque formation in the interstitial space of the renal papilla. CaPh crystals and organic matrix initially are deposited along the basement membranes of the thin loops of Henle and extend further into the interstitial space to the urothelium, constituting the so-called Randall plaques, which are regularly found during endoscopy of patients who form CaOx stones. These CaPh crystals seem to be the origin for the development of future CaOx stones, which form by the attachment of further matrix molecules and CaOx from the urine to the plaque. The driving forces, the exact pathogenetic mechanisms, and the involved matrix molecules are still largely unknown. Completely different pathomechanisms obviously lead to the common clinical diagnosis of ‘‘CaOx stone former.’’ Although the site of stone formation has become clear, the initial trigger for crystallization remains under discussion. A multifactorial process seems to be the most probable. An increased urinary calcium excretion appears to play an important role because the measured papillary coverage correlates with urinary calcium and urine pH. Earlier examinations showed higher calcium and oxalate concentrations within the renal papilla than within the renal cortex, medulla, or urine. An acidic urinary pH leads to an increased bicarbonate resorption into the renal medulla and a consecutive increasing interstitial pH that may promote apatite depletion. Recent findings have helped us understand the mechanism of CaOx stone formation on the Randall plaques. Stones derived from biopsies of renal papillae were evaluated by immunohistochemistry, scanning microscopy, and infrared spectroscopy. These examinations demonstrated that the urothelium was lost at the attachment side. Organic matrix (mainly Tamm-Horsfall protein and osteopontin) and crystals formed belts that are obviously required to allow further crystal depletion and consequently CaOx stone formation.
X-ray kidney ultrasound.
Computed tomography scan.
Clinical diagnosis is usually made on the basis of the location and severity of the plan.
Pain in the back occurs when calculi produce an obstruction in the kidney.
Culture of urine sample to exclude urinary infection.
Urine test-microscopic study of urine-show proteins, red blood cells bacteria, cellular casts and crystals.
Intravenous pyelogram (IVP).
24-hours urine collection test-measures total daily urinary volume, magnesium, sodium, uric acid, citrate, calcium oxalate and phosphate.
The treatment of urolithiasis or the removal of stone involves in the following:
Ureteroscopic stone removal:
Ureteroscopic stone removal is achieved by passing a small fiber optic instrument (an ureteroscopes) through the urethra and bladder into the ureter.
A small tube may be left in the ureter for several days after treatment to help the lining of the ureter to heal.
Precutaneous Nephrolithotomy: 
Precutaneous nephrolithotomy, or PCNL, is a procedure for removing medium-sized or larger renal calculi (kidney stones) from the patient’s urinary tract by means of a nephroscope passed into kidney through a tract created in the patient’s back.
The purpose PCNL is the removal of renal calculi in order to relieve pain, bleeding into or obstruction of the urinary tract and / or urinary tract infections resulting from blockages.
By minimising the risk factors we can overcome development of disease in future.
Both surgical and medical treatment is necessary for the complete management of patients of urolithiasis. 
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