UROLITHIASIS
Urolithiasis refers to the presence of stones (calculi) in the urinary system.
Types Of Calculi- Majority of stones are composed mainly of calcium oxalate crystals; the rest are composed of calcium phosphate salts, uric acid, struvite (magnesium, ammonium and phosphate), or the amino acid cystine.
Incidence- Occurs more in men than women; peak age of onset is 120-40 years.
Causes And Predisposing Factors:
a. Hypercalcemia and hypercalciuria caused by hyperparathyroidism, renal tubular acidosis, multiple myeloma and excessive intake of vit D, milk and alkali.
b. Chronic dehydration; poor fluid intake and immobility.
c. Diet high is purines [and abnormal purine metabolism (hyperuricemia and gout)]. (1
d. Genetic predisposition [for urolithiasis or genetic disorders (cystinuria)]
e. Chronic infection [ with urea-splitting bacteria (proteus vulgaris)]
f. Chronic obstruction with stasis of urine, foreign bodies within the urinary tract.
g. Excessive oxalate absorption in inflammatory bowel disease and bowel resection or ileostomy.
h. Living in mountainous, desert or tropical areas.
Pathophysiology
Causes and predisposing factors
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Crystallization of substances excreted in the urine stones may be found anywhere in the urinary system and vary in size from granular deposits (called sand or grovel) to bladder stones the size of an orange.
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Some stones may lodge in the renal pelvis, ureters, or bladder neck causing obstruction, edema, 20 infection and in some cases, nephron Gamage. [people who have had 2 stones tend to have recurrences).
Clinical Manifestations
1. Sharp severe pain sudden onset depending on the site called renal / ureteral colic.
2. Renal colic originates deep in lumbar region, radiates around the side and down towards testicle in male and bladder in female.
3. Ureteral colic radiates towards genitalia and thigh. Urine frequent and haematuria [may be present]. [Gl symptoms include] nausea, vomiting, diarrhoea, abdominal discomfort [due to Reno intestinal reflexes and shared nerve supply (celiac ganglion) both the ureters and intestine.
Obstruction [stones blocking the flow of urine will produce symptoms of UTI, chills and fever.
4. [Pain may be intermittent proximal to the stone urine flows indicates that the stone has moved. Ureter dilates stone moves to a new site pain returns).
Diagnostic Evaluations
1. IVP determines site and evaluates degree of obstruction. [uroradiologic studies are necessary when stones or radiolucent;] retrograde or out grade pyelography.
2. CT scan - differentiates a nonopaque stone and tumor. Spiral CT- assess for stone in ureter.
3. Analysis of available stone material [crystals can be identified by polarization microscopy, x-ray diffraction and infrared spectroscopy].
4. Urinalysis haematuria and pyuria, urine culture and drug sensitivity studies.
5. History of previous stone formation prescribed or over-the-counter drugs, dietary supplements family history.
6. Blood chemistries and 24-hr. urine test for measurement of calcium, creatinine Na, Ph, and total volume.
Medical Management
Diet & Therapy
1. Most stones contain calcium phosphate or other substances,
2. Calcium and Phosphorus content is moderately reduced.
3. Sodium cellulose phosphate - prevent Ca stones) preventing [It binds Ca from food in the intestinal tract, reducing the amount. of calcium absorbed in to the circulation].
4. If increased parathormone production [(resulting in increased serum calcium levels in blood and urine) is a factor in] formation of stones, thiazide therapy reduces the calcium loss in the urine and Jowers the elevated parathormone levels.
5. Phosphatic calculi a diet low in phosphorus prescribed. Aluminium hydroxide gel is prescribed.
[Aluminium. Hydroxide combines with excess phosphorus leads to excretion of it through intestinal trac)]
6. For uric acid stones, low purine diet [(reduced the out put of uric acid in the urine)] Avoid foods high is purine (skellfish and organ meat) and limit other proteins. All opuriuol (zyloprine) - given to
reduce serum and urinary uric acid excretion. The urine is alkalinized.
7. For cystine stones, a low protein diet is given the urine is alkalinized, and penicillamine is give/
[to reduce the amount of cystine in the urine].
8. For oxalate stones, a dilute urine is maintained and the intake of oxalate is limited. Avoid green leafy vegetables, beans, celery, Ceria beets, rhubarb, chocolate, tea, coffee and peanuts,
Surgical Management
Indication Surgery:
1. If stones too large
2. If stones associated with bacteriuria/symptomatic infection.
3. If stones causing impaired renal function.
4. If stones causing persistent pain, nausea or ileus.
5. Inability to treat Patient medically
6. Patient with solitary kidney.
1. Extracorporeal shock wave lithotripsy (ESWL) (for stones <2 cms) in diameter [80% of stones fall into this category.] High energy shock waves are directed at the kidney stone, disintegrating it into minute particles that pass in the urine. [A shock wave is a large, condensed wave of energy produced by high speed motion)]. Patient is placed on specially designed table and immersed in a water bath or placed on an adjustable stretcher positioned over a cushion of water.
a. In H2O bath model, shock waves travel throw water surrounding the Patient.
b. In cushion model, a layer of gel lies between the stretcher and water; shock waves move through' the cushion and gel]
c. Position of the kidney stone is located by fluoroscopy, and the shock waves are targeted directly at the stone. [The shock waves do not affect soft tissue.
d. It can be repeated for recurrent stones].
Complication- pain, urinary infection and temporary bleeding around kidney.
2. Percutaneous Nephrostolithotomy (PCNL) for stones larger than 2.5 cm in diameter.
Under fluoroscopic / ultrasound guidance, a needle is advanced into 1 collecting system; guide wire is advanced in to renal pelvis or ureter.
Tract is dilated with mechanical dilator or high-pressure, Balloon dilator until nephroscope can be inserted up against stone.
Stones can be broken apart with hydraulic snock waves or a laser beam administered by way of nephroscope; fragments are removed using forceps, graspers or basket.
May be combined with ESWL.
Complication - haemorrhage, infection and extravasations of urine.
3. Percutaneous stone dissolution (chemolysis). A multiholed nephrostomy tube (catheter) is placed in kidney; offers a pathway for introduction of solvent (depending on chemical composition of stone) to be infused into stone. A second catheter may be used for drainage.
a. Used for struvite, uric acid and cystine stones.
b. May be used to shrink large stones before other retrieval methods or to irrigate debris after lithotripsy procedures.
c. Irrigating solution introduced at a continuous rate that Patient can above tolerate flank pain or elevation of intrarenal pressure. Glone 25 m. H2O (most IV. Infusion pumps can be adapted for use and set to alarm should pressure. exceed this level.)
d. The Patient receives antimicrobial agents before during and after procedure to maintain sterile urine.]
4. Ureteroscopy used for distal ureteral calculi may be used for midureteral calculi. Flexible or rigid uteroscopes are used in conjunction with basket or graspers. Electrohydraulic ultrasonic or laser equipment may also be used to fragment stone.
5. Stent may be Complications infection [(renal septic shock)] and inserted left in place after N at perirenal abscess, pyelonephritis, thrombophlebitis sand pulmonary Embolism (associated tur maintain with immobilization).
Nursing Management:
1. Give prescribed narcotic analgesic [usually IV or IM] [until! cause of pain can be removed]. Toj Iretoriala
2. Encourage Patient to assume position that brings some relief.
3. Administer Antiemetics (IM or rectal suppository) as indicated for nausea
4. Administer Fluids orally or IV(of vomiting) to reduce concentration of urinary crystalloids and ensure adequate urine out put,
5. Monitor total urine output and patterns of voiding report oliguria or anuria
6. Strain all urine thro' strainer or gauze to harvest the stone; [Urine acid stones may crumble]. Crush clots and inspect sides of urinal or bedpan for clinging stones or fragments.
7. [For OP treatment, the Patient may use a coffee filter to strain urine]
8. Administer Parenteral or oral antibiotics as prescribed.
9. Assess urine for color, cloudiness and odor.
10. Obtain vital signs, and monitor for fever and symptoms of impending sepsis (tachycardia, hypotension).
11. Warm that some blood may appear in urine for several weeks after surgical intervention.
12. Encourage frequent walking to assist in passage of stone fragments. A stent may be inserted and left in place after surgery to maintain patency of ureter.
Open surgical procedures indicated for only 1-2% of all stones.
a Pyelolithotomy-removal of stones from kidney pelvis.
b. Coagulum pyelolithotomy intraoperative injection of certain coagulation factors into the renal pelvis, producing a coagulum that entraps the stones and expedites their removal.
c. Nephrolithotomy-incision into kidney for removal of stone.
d. Nephrectomy removal of kidney [indicated when kidney is extensively and irreparably damaged and is no longer a functioning organ.] partial nephrectomy sometimes done.
e. Uretetolithotomy removal of stone in ureter.
f. Cystolithotomy-removal of stone from bladder.
Complications
1. Obstruction [from the remaining stone fragments].
2. Infection [from disst. of infected stone particles or bacteria resulting from obstruction].
3. Perirenal hematoma - [from bleeding around the kidney caused by trauma of shock waves or laser treatment].
4. Impaired renal function from prolonged obstruction before treatment and removal
Prevention of Recurrent Stone Formation
1. For Patients with calcium oxalate stones.
a. instruct on diet avoid excesses of Ca and Phosphorus; maintain a low Na diet (Na restriction reduces amount. of Ca absorbed in intestine).
b. Teach purpose of drug therapy thiazide diuretics to reduce urine calcium excretion allopurinol therapy to reduce uric acid concentration.
2. For Patients with uric acid stones.
a. Teach methods to alkalinize urine to enhance urate solubility.
b. Instruct on testing urine Ph.
c. Teach purpose of taking allopurinol - to lower uric acid concentration.
d. Provide information about reduction of dietary purine intake (low protein - red meat, fish, fowl).
3. For Patients with infection (struvite) stone.
a. Teach signs and symptoms of urinary infection (in patients with neurologic or spinal cord disease; teach use of dipsticks to evaluate urine for nitrites and leukocytes), encourage to report infection immediately; must be treated vigorously.
b. Try to avoid prolonged periods of recumbency slows renal drainage and afters calcium metabolism.
4. For Patients with cystine stones.
a. Teach Patient to alkalinize urine by taking sodium bicarbonate tablets (soda mint) to increased cystine solubility; instruct Patient how to test urine PH with a PH indicator.
b. Teach Patient about drug therapy with D- penicillamine - to lower cystine concentration or dissolution by direct irrigation with thiol derivatives.
5. For all Patients with stone disease.
a. Explain. need for increased fluid intake (24 hr urinary output > 2L) lowers the concentration of substances involved in stone formation.
Drink enough fluids to achieve a urinary volume of 2-3 L or more /24Hrs.
Drink larger amounts during periods of strenuous exercise, if Patient perspires freely.
Take fluids in evening to guarantee a high urine flow during the night.
b. Encourage a diet low in sugar and animal proteins refined CHO appear to lead to hypercalciuria and urolithiasis, animal proteins increase urine excretion of Ca, uric acid and oxalate.
c. Increased consumption of fibre - inhibits Ca and oxalate absorption.
d. Save any stone passed for analysis (only Patients with > 1 episode of urolithiasis are advised to have a metabolic evaluation.
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