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Renal calculi

Kidney stones, also known as nephrolithiases, urolithiases or renal calculi, are solid accretions (crystals) of dissolved minerals in urine found inside the kidneys or ureters. They vary in size from as small as a grain of sand to as large as a golf ball. more...

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Kidney stones typically leave the body in the urine stream; if they grow relatively large before passing (on the order of millimeters), obstruction of a ureter and distention with urine can cause severe pain most commonly felt in the flank, lower abdomen and groin.


Conventional wisdom has held that consumption of too much calcium can aggravate the development of kidney stones, since the most common type of stone is calcium oxalate. However, strong evidence has accumulated demonstrating that low-calcium diets are associated with higher stone risk and vice-versa for the typical stone former.

Other examples of kidney stones include struvite (magnesium, ammonium and phosphate), uric acid, calcium phosphate, or cystine (the amino acid found only in people suffering from cystinuria). The formation of struvite stones is associated with the presence of urease splitting bacteria (Klebsiella, Serratia, Proteus, Providencia species) which can split urea into ammonia, most commonly Proteus mirabilis.


Kidney stones are usually idiopathic and asymptomatic until they obstruct the flow of urine. Symptoms can include acute flank pain (renal colic), nausea and vomiting, restlessness, dull pain, hematuria, and possibly fever if infection is present. Acute renal colic is described as one of the worst types of pain that a patient can suffer from. But there are also people who have no symptoms until their urine turns bloody—this may be the first symptom of a kidney stone.

Diagnosis & Investigation

Diagnosis is usually made on the basis of the location and severity of the pain, which is typically colic in nature (comes and goes in spasmodic waves). Radiological imaging is used to confirm the diagnosis and a number of other tests can be undertaken to help establish both the possible cause and consequences of the stone.

The relatively dense calcium renders these stones radio-opaque and they can be detected by a traditional X-ray of the abdomen that includes Kidneys, Ureters and Bladder—KUB. This may be followed by an IVP (Intravenous Pyelogram) which requires roughly about 50ml of a special dye to be injected into the bloodstream that goes straight to the kidneys and helps outline any stone on a repeated X-ray. Computed tomography, a specialized X-ray, is by far the most accurate diagnostic test for the detection of kidney stones.

Investigations typically carried out include:

  • Culture of a urine sample to exclude urine infection (either as a differential cause of the patient's pain, or secondary to the presence of a stone)
  • Blood tests: Full blood count for the presence of a raised white cell count (Neutrophilia) suggestive of infection, a check of renal function and if raised blood calcium blood levels (hypercalcaemia).
  • 24 hour urine collection to measure total daily urinary calcium, oxalate and phiosphate.


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Test yourself on renal nursing
From Nursing, 10/1/01

Even if you don't work in the analysis unit, you should be familiar with renal conditions. Take this least to see how you measure up.

1. Which of the following conditions is a common cause of prerenal acute renal failure?

1. atherosclerosis

2. decreased cardiac output

3. benign prostatic hyperplasia

4. rhabdomyolysis

2. Care for an indwelling urinary catheter should include which of the following interventions?

1. Insert the catheter using clean technique.

2. Keep the drainage bag on the patient's bed.

3. Clean around the catheter at the meatus with soap and water.

4. Lay the drainage bag on the floor to allow for maximum drainage through gravity.

3. Which of the following methods should you use to collect a specimen for urine culture?

1. Have the patient void in a clean container.

2. Clean the foreskin of the penis of uncircumcised men before specimen collection.

3. Have the patient void into a urinal, then pour the urine into the specimen container.

4. Have the patient begin the stream of urine in the toilet and catch the urine in a sterile container midstream.

4. A patient is undergoing peritoneal dialysis. The dialysate dwell time is completed, and the clamp is opened to let the dialysate drain. You note that drainage has stopped and only 500 ml has drained; the amount of dialysate instilled was 1,500 ml. Which of the following would you do first?

1. Change the patient's position.

2. Check the catheter for kinks or obstructions.

3. Clamp the catheter and instill more dialysate at the next exchange time.

4. Call the nephrologist.

5. A patient has transurethral prostactectomy for benign prostatic hyperplasia. He's currently being treated with a continuous bladder irrigation and is complaining of an increase in severity of bladder spasms. Which of the following should you do first?

1. Stop the irrigation and call the surgeon.

2. Administer a belladonna and opium suppository as ordered by the surgeon.

3. Check for the presence of clots and make sure that the catheter is draining properly.

4. Administer an oral analgesic.

6. Proper maintenance of a continuous bladder irrigation system includes which of the following interventions?

1. Regulate irrigant flow to maintain red urine.

2. Regulate irrigant flow to maintain a good outflow of pink urine.

3. Maintain a slow flow rate of irrigant to prevent bladder distension.

4. Stop the irrigation if a lot of urine is leaking around the catheter.

7. A patient is admitted with a diagnosis of hydronephrosis secondary to calculi. The calculi have been removed and postobstructive diuresis is occurring. Which of the following should you do?

1. Take vital signs every 8 hours.

2. Weigh the patient every other day.

3. Assess urine output every shift.

4. Monitor the patient's electrolyte levels.

8. A patient has a history of chronic renal failure and receives hemodialysis treatments three times a week through an arteriovenous (AV) fistula in his left arm. Which of the following interventions is included in his care?

1. Keep the AV fistula dry.

2. Keep the AV fistula wrapped in gauze.

3. Take blood pressure in the left arm.

4. Assess the AV fistula for a bruit and thrill.

9. Serum creatinine levels provide the most accurate picture of renal function because:

1. serum creatinine is rapidly absorbed by the renal tubules.

2. a slow urine flow through the kidneys increases creatinine levels.

3. elevated serum creatinine levels indicate a decrease in glomerular function.

4. serum creatinine levels are related to the rate of urine flow through the kidneys.

10. Which of the following factors causes the nausea associated with renal failure?

1. oliguria

2. gastric ulcers

3. electrolyte imbalance

4. accumulation of metabolic wastes

11. Which of the following patients is at greatest risk for developing acute renal failure?

1. a dialysis patient who gets influenza

2. a teenager who has an appendectomy

3. a pregnant woman who has a fractured femur

4. a patient with diabetes who has a heart catheterization


1. 2. Prerenal refers to renal failure due to an interference with renal perfusion. Decreased cardiac output causes a decrease in renal perfusion, which leads to a lower glomerular filtration rate. Atherosclerosis and rhabdomyolysis are causes of intrarenal failure. Benign prostatic hyperplasia is an example of postrenal failure.

2. 3. Cleaning around the meatus at the catheter site is important to decrease the chance of infection. The catheter should be inserted using sterile, not clean, technique. Keeping the drainage bag on the patient's bed causes backflow of urine into the urethra, increasing the chance of infection. The drainage bag shouldn't be placed on the floor because of the increased risk of infection due to microorganisms. It should hang on the bed in a dependent position.

3. 4. Catching urine midstream reduces the amount of contamination by microorganisms at the meatus. Voiding in a clean container is done for a random specimen, not a clean-catch specimen for urine culture. When cleaning an uncircumcised male, retract the foreskin and clean the glans penis to prevent specimen contamination. Voiding in a urinal doesn't allow for an uncontaminated specimen because the urinal isn't sterile.

4. 2. The first intervention should be to check for kinks and obstructions because that could be preventing drainage. After checking for kinks, have the patient change position to promote drainage. Don't give the next scheduled exchange until the dialysate is drained because abdominal distension will occur, unless the output is within the parameters set by the nephrologist. If you can't get more output despite checking for kinks and changing the patient's position, call the nephrologist to determine the proper intervention.

5. 3. Blood clots and blocked outflow of the urine can increase spasms. Don't stop the irrigation as long as the catheter is draining because clots will form. Give a belladonna and opium suppository as ordered to relieve spasms but only after assessing the drainage. Give an oral analgesic if the spasms are unrelieved by the belladonna and opium suppository.

6. 2. The irrigant should be infused at a rate fast enough to maintain a good outflow of pink urine. Red urine indicates inadequate irrigation and possible clot formation. Bladder distension shouldn't occur as long as the system is draining properly. If urine is leaking around the catheter, suspect clot formation on the catheter tip, which will need manual irrigation. Don't stop the irrigation because doing so would increase the potential. for clot formation.

7. 4. Postobstructive diuresis seen in hydronephrosis can cause electrolyte imbalances; lab values must be checked so electrolytes can be replaced as needed. Take vital signs frequently for the first 4 hours. Weigh the patient daily to assess fluid status more closely and assess urine output hourly.

8. 4. Assessing the AV fistula for a bruit and thrill is important because their absence indicates a nonfunctioning fistula. When not being used for dialysis, the AV fistula site may get wet. Immediately after a dialysis treatment, cover the access site with adhesive bandages. No blood pressure measurements or venipunctures should be taken in the arm with the AV fistula.

9. 3. Creatinine is filtered by the glomeruli and isn't reabsorbed by the renal tubules. A defect in glomerular filtration would cause an increase in the serum creatinine level. Urea is rapidly reabsorbed by renal tubules and is related to the rate of urine flow through the kidneys. A slow urine flow can increase the blood urea nitrogen level without renal disease.

10. 4. Although patients with renal failure can develop gastric ulcers, nausea usually is related to metabolic wastes that accumulate when the kidneys can't eliminate them. The patient has oliguria and electrolyte imbalances, but these don't directly cause nausea.

11. 4. Patients with diabetes are prone to renal insufficiency and renal failure. The contrast medium used for heart catheterization must be eliminated by the kidneys, which further stresses them and may produce acute renal failure. A dialysis patient already has end-stage renal disease and wouldn't develop acute renal failure. A teenager who has an appendectomy and a pregnant woman who fractures a femur aren't at increased risk for renal failure.

Source: NCLEX-RN Questions and Answers Made Incredibly Easy!, Springhouse Corp., 2000.

Copyright Springhouse Corporation Oct 2001
Provided by ProQuest Information and Learning Company. All rights Reserved

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