Diagnosis of Kidney Stones
Diagnosis of kidney stone disease involves a medical history,
physical examination, laboratory evaluation, and imaging
tests. The physician determines if the patient has a history
of kidney stones, documents past medical conditions, and
evaluates present symptoms. Physical examination may be
difficult if the patient is experiencing severe pain and is
unable to remain still. Lightly tapping on the kidney region
often worsens the pain. Fever may indicate a urinary tract
infection that requires antibiotics.
Laboratory tests include urinalysis to detect the presence of
blood (hematuria) and bacteria (bacteriuria) in the urine.
Other tests include blood tests for creatinine (to evaluate
kidney function), BUN and electrolytes (to detect
dehydration), calcium (to detect hyperparathyroidism), and a
complete blood count (CBC; to detect infection).
Kidney Stone Imaging tests
Imaging tests used to diagnose kidney stones include
ultrasound, intravenous pyelogram (IVP), retrograde pyelogram,
and computerized tomography (CT) scan.
Ultrasound
This test uses high-frequency sound waves to produce pictures
of internal structures (e.g., organs, kidney stones).
Ultrasound can detect a dilated (stretched) upper urinary
tract and kidney caused by a stone lodged in the ureter, but
usually cannot detect small stones, especially those located
outside the kidney. It is the preferred imaging method for
kidney stone patients who are pregnant.
Intravenous Pyelogram (IVP)
This test involves taking a series of x-rays after injecting a
contrast agent (dye) into a vein. The contrast agent flows
through the veins, is excreted by the kidneys, and improves
the x-ray images of the kidneys and ureters. If a kidney stone
is blocking a ureter, the contrast agent builds up in the
affected kidney and is excreted more slowly. Most kidney
stones (e.g., calcium stones) can be precisely located using
this procedure. There is a slight risk for an allergic
reaction to the contrast agent during this procedure and
overall kidney function must be normal. IVP can take a very
long time if the blockage to the kidney is severe.
Retrograde Pyelogram
A cystoscopy (i.e., a procedure in which a telescopic
instrument is inserted into the urethra) is performed to
locate the opening from the ureter to the bladder. The
contrast agent is injected directly into this opening and an
x-ray is taken to locate the kidney stone.
This procedure eliminates the risk for an allergic reaction to
the contrast agent because the dye does not reach the
bloodstream, but it may require anesthesia. While retrograde
pyelogram is the most reliable method for visualizing the
urinary system and detecting stones, it is generally used only
when other imaging methods are inadequate or unsuccessful.
CT (Computerized Tomography) Scan
This test uses a scanner and a computer to create images of
the urinary system. It is performed quickly but may have
difficulty detecting small stones located near the bladder. CT
scan can also help identify medical conditions (e.g., ruptured
appendix, bowel obstruction) that cause symptoms similar to
kidney stones.
Newer scanners do not require a contrast agent. The
non-contrast CT scan is the most common imaging test used to
evaluate a possible kidney stone attack. If any stones are
found, a plain abdominal x-ray is also taken to determine
their size, shape, and orientation. X-rays are used for
follow-up studies to monitor the stones’ progress.
The Austin Diagnostic Clinic, A
Multi-Specialty Medical Clinic
12221 MoPac Expressway North |
Austin, TX 78758 | 512.901.1111
Serving the communities of Austin, Round Rock, Pflugerville, San
Marcos and
Central Texas since 1952
We accept Visa, Mastercard, Discover and American Express
This
website and its contents may not be reproduced in whole or in part
without written permission. The Austin Diagnostic
Clinic and its associated logo are registered State of Texas
trademarks and may not be used without written permission.
