History
Some of the features of the patient's history that may be relevant to stone disease are presented below:
Features of the Patient History Relevant to Stone Disease
-
- Family history of stones
- Age of onset of stones
- Past medical history
- Fluid intake and Diet Patterns
- Medications
- Clinical course
- History of stones
- Previous surgery (type and number)
- History of infection
- Composition of previous stones
Family History of Stones
A family history of stone disease maybe associated with an autosomal recessive disorders, resulting in an enzyme defect. This enzyme defect may cause a condition known as cystinuria and primary hyperoxaluria. In an autosomal recessive disorder, one expects to see the disease in one or more of the patient's siblings. In the family of a patient with autosomal dominant diseases, such as renal tubular acidosis (RTA) or the syndrome of idiopathic calcium oxalate urolithiasis, stone formation may be present in each generation and in both sexes. A strong family history of stone formation within the urinary tract may indicate more severe disease.
Age of Onset of Stones
Knowing the age of onset of stones may also be helpful. Stone formation beginning in the young child suggests primary hyperoxaluria or other enzymatic defects. On the other hand, cystinuria, idiopathic calcium oxalate urolithiasis, and primary hyperparathyroidism typically begin around puberty or in the mid-teens. Stone formation resulting from infection and/or obstruction related to congenital malformations of the urinary tract often present before the age of 5.
Past Medical History
Past medical history may at times be helpful, particularly in the case of immobilization resulting from an injury in children with active growing bones. This immobilization often causes mild to moderate hypercalcemia with associated hypercalciuria leading to stone formation within the urinary tract.
Fluid Intake and Diet Pattern
Low fluid intake and unusual dietary practices may bring out a tendency to stone formation in patients with underlying idiopathic calcium oxalate stone disease. If previous stones are available, they should be collected and sent for analysis. Previous x-ray studies may be very helpful in determining the metabolic activity of stone formation.
Diagnosis
It may be difficult to diagnose stones in children and younger infants. The most commonly presented symptom is pain seen in 40-75% of patients. Unlike the classic colicky, flank pain seen in adults, diffuse abdominal pain may be seen in children. Microscopic or gross hematuria may be seen in 25-40% of children. Symptoms attributable to a urinary tract infection, including fever, dysuria, frequency, and/or urgency may be seen in 10-30% of children. Urinary calculi found incidentally on x-rays are seen more frequently in younger children as older children more often present with flank or abdominal pain.
There are certain situations in which children with stones should be suspected. These include children with recurrent urinary tract infections, recurrent severe abdominal pain, and recurrent or persistent gross hematuria, not associated with glomerulonephritis. A family history for urinary tract stones has been seen in 20-37% of children. Stone formation is also extremely rare in non-white children, and is usually associated with a severe metabolic disorder or anatomical anomaly.
X-ray studies are necessary for making the precise diagnosis in children with signs and symptoms suggestive of urinary tract stones. Abdominal ultrasound or a plain abdominal x-ray (KUB) is the most reliable initial tests in younger children. These studies are less invasive and more sensitive than an IVP. Recently, spiral CT scan has gained popularity in diagnosing urinary tract stones in adults and children. Once the diagnosis of stone disease is made, an IVP should be performed as other anatomical defects and renal scarring may be identified.
A urinalysis is also helpful in establishing the diagnosis of urinary tract stones. Hematuria and bacteria can be identified on inspection of the urine. In addition, crystals can be strongly suggestive of specific types of stones. With a urine pH greater than 6, crystallization of calcium phosphate stones may occur. pH urines greater than 7 often indicate struvite stones. If the urine pH is less than 6.0, there is increasing likelihood in the production of cystine and uric acid calculi.
Laboratory Evaluation
-
- Urine and Blood Work
- Radiographic Studies
- Stone Analysis
- 24-Hour Urine
Urine and Blood Work
Initial laboratory studies should include a first morning (a.m.) urinalysis (including pH), urine culture and antibiotic sensitivity, and measurement of serum calcium, phosphorus, sodium, potassium, chloride, bicarbonate, uric acid, and creatinine levels.
Radiographic Studies
The anatomy of the urinary tract should be defined with necessary radiographs. A kidney, ureter, bladder (KUB) X-ray with tomograms and an excretory urogram most often are used at the time of the initial evaluation. Ultrasonography can be helpful when one is looking for obstruction and non-opaque stones. However, the renal ultrasound has not been as helpful as roentgenograms in assessing stone number, stone mass and stones in the ureter. Recently, a spiral CT scan has gained popularity in diagnosing urinary tract stones in adults and children.
Stone Analysis
If a stone is passed in the urine, it should be collected and analyzed. Infrared spectroscopy provides useful and accurate information on stone composition.
24-Hour Urine
A 24-hour urine collection should be performed but not while the patient is experiencing acute distress with a stone. All of the constituents that are measured in the 24-hour urine collection are dependent upon fluid and diet intake. Therefore, under most situations, the 24-hour urine collection should be completed when the patient is stone-free, asymptomatic and on a normal diet and fluid consumption. The initial studies should include a measurement of total urine volume, calcium, oxalate, uric acid, citrate, cystine, phosphate, and creatinine. In some instances, the collection of two or three 24-hour urine samples is helpful to better identify specific abnormalities.
Some of the features of the patient's history that may be relevant to stone disease are presented below:
Features of the Patient History Relevant to Stone Disease
-
- Family history of stones
- Age of onset of stones
- Past medical history
- Fluid intake and Diet Patterns
- Medications
- Clinical course
- History of stones
- Previous surgery (type and number)
- History of infection
- Composition of previous stones
Family History of Stones
A family history of stone disease maybe associated with an autosomal recessive disorders, resulting in an enzyme defect. This enzyme defect may cause a condition known as cystinuria and primary hyperoxaluria. In an autosomal recessive disorder, one expects to see the disease in one or more of the patient's siblings. In the family of a patient with autosomal dominant diseases, such as renal tubular acidosis (RTA) or the syndrome of idiopathic calcium oxalate urolithiasis, stone formation may be present in each generation and in both sexes. A strong family history of stone formation within the urinary tract may indicate more severe disease.
Age of Onset of Stones
Knowing the age of onset of stones may also be helpful. Stone formation beginning in the young child suggests primary hyperoxaluria or other enzymatic defects. On the other hand, cystinuria, idiopathic calcium oxalate urolithiasis, and primary hyperparathyroidism typically begin around puberty or in the mid-teens. Stone formation resulting from infection and/or obstruction related to congenital malformations of the urinary tract often present before the age of 5.
Past Medical History
Past medical history may at times be helpful, particularly in the case of immobilization resulting from an injury in children with active growing bones. This immobilization often causes mild to moderate hypercalcemia with associated hypercalciuria leading to stone formation within the urinary tract.
Fluid Intake and Diet Pattern
Low fluid intake and unusual dietary practices may bring out a tendency to stone formation in patients with underlying idiopathic calcium oxalate stone disease. If previous stones are available, they should be collected and sent for analysis. Previous x-ray studies may be very helpful in determining the metabolic activity of stone formation.
It may be difficult to diagnose stones in children and younger infants. The most commonly presented symptom is pain seen in 40-75% of patients. Unlike the classic colicky, flank pain seen in adults, diffuse abdominal pain may be seen in children. Microscopic or gross hematuria may be seen in 25-40% of children. Symptoms attributable to a urinary tract infection, including fever, dysuria, frequency, and/or urgency may be seen in 10-30% of children. Urinary calculi found incidentally on x-rays are seen more frequently in younger children as older children more often present with flank or abdominal pain.
There are certain situations in which children with stones should be suspected. These include children with recurrent urinary tract infections, recurrent severe abdominal pain, and recurrent or persistent gross hematuria, not associated with glomerulonephritis. A family history for urinary tract stones has been seen in 20-37% of children. Stone formation is also extremely rare in non-white children, and is usually associated with a severe metabolic disorder or anatomical anomaly.
X-ray studies are necessary for making the precise diagnosis in children with signs and symptoms suggestive of urinary tract stones. Abdominal ultrasound or a plain abdominal x-ray (KUB) is the most reliable initial tests in younger children. These studies are less invasive and more sensitive than an IVP. Recently, spiral CT scan has gained popularity in diagnosing urinary tract stones in adults and children. Once the diagnosis of stone disease is made, an IVP should be performed as other anatomical defects and renal scarring may be identified.
A urinalysis is also helpful in establishing the diagnosis of urinary tract stones. Hematuria and bacteria can be identified on inspection of the urine. In addition, crystals can be strongly suggestive of specific types of stones. With a urine pH greater than 6, crystallization of calcium phosphate stones may occur. pH urines greater than 7 often indicate struvite stones. If the urine pH is less than 6.0, there is increasing likelihood in the production of cystine and uric acid calculi.
-
- Urine and Blood Work
- Radiographic Studies
- Stone Analysis
- 24-Hour Urine
Urine and Blood Work
Initial laboratory studies should include a first morning (a.m.) urinalysis (including pH), urine culture and antibiotic sensitivity, and measurement of serum calcium, phosphorus, sodium, potassium, chloride, bicarbonate, uric acid, and creatinine levels.
Radiographic Studies
The anatomy of the urinary tract should be defined with necessary radiographs. A kidney, ureter, bladder (KUB) X-ray with tomograms and an excretory urogram most often are used at the time of the initial evaluation. Ultrasonography can be helpful when one is looking for obstruction and non-opaque stones. However, the renal ultrasound has not been as helpful as roentgenograms in assessing stone number, stone mass and stones in the ureter. Recently, a spiral CT scan has gained popularity in diagnosing urinary tract stones in adults and children.
Stone Analysis
If a stone is passed in the urine, it should be collected and analyzed. Infrared spectroscopy provides useful and accurate information on stone composition.
24-Hour Urine
A 24-hour urine collection should be performed but not while the patient is experiencing acute distress with a stone. All of the constituents that are measured in the 24-hour urine collection are dependent upon fluid and diet intake. Therefore, under most situations, the 24-hour urine collection should be completed when the patient is stone-free, asymptomatic and on a normal diet and fluid consumption. The initial studies should include a measurement of total urine volume, calcium, oxalate, uric acid, citrate, cystine, phosphate, and creatinine. In some instances, the collection of two or three 24-hour urine samples is helpful to better identify specific abnormalities.