A
kidney stone, also known as a
renal calculus (from the
Latin ren, "kidney" and
calculus, "pebble") is a solid
concretion or
crystal aggregation formed in the kidneys from
dietary minerals in the
urine.
Urinary stones are typically classified by their location in the
kidney (nephrolithiasis),
ureter (ureterolithiasis), or
bladder (
cystolithiasis), or by their chemical composition (
calcium-containing,
struvite,
uric acid, or other compounds). Kidney stones are a significant source of
morbidity. 80% of those with kidney stones are men. Men most commonly experience their first episode between age 30–40 years, while for women the age at first presentation is somewhat later.
Kidney stones typically leave the body by passage in the urine stream, and many stones are formed and passed without causing symptoms. If stones grow to sufficient size (usually at least 3 millimeters (0.12 in) they can cause obstruction of the ureter. Ureteral obstruction causes
postrenal azotemia and
hydronephrosis (distension and dilation of the
renal pelvis and
calyces), as well as
spasm of the ureter. This leads to
pain, most commonly felt in the
flank (the area between the ribs and hip), lower abdomen and
groin (a condition called
renal colic). Renal colic can be associated with
nausea,
vomiting,
fever,
blood in the urine,
pus in the urine, and
painful urination. Renal colic typically comes in waves lasting 20 – 60 minutes, beginning in the flank or lower back and often radiating to the groin or genitals. The
diagnosis of kidney stones is made on the basis of information obtained from the
history,
physical examination,
urinalysis, and
radiographic studies.
ultrasound examination and
blood tests may also aid in the diagnosis.
When a stone causes no symptoms,
watchful waiting is a valid option. For symptomatic stones,
pain control is usually the first measure, using medications such as
non-steroidal anti-inflammatory drugs (NSAIDs) or
opioids. More severe cases may require surgical intervention. For example, some stones can be shattered into smaller fragments using
extracorporeal shock wave lithotripsy (ESWL). Some cases require more
invasive forms of surgery. Examples of these are
cystoscopic procedures such as
laser lithotripsy, or
percutaneous techniques such as
percutaneous nephrolithotomy. Sometimes, a tube (
ureteral stent) may be placed in the ureter to bypass the obstruction and alleviate the symptoms.
kidney stones symptoms and signs?
While some kidney stones may not produce symptoms (known as "silent" stones), people who have kidney stones often report t
he sudden onset of excruciating, cramping pain in their low back and/or side, groin, or abdomen. Changes in body position do not relieve this pain. The abdominal, groin, and/or back pain typically waxes and wanes in severity, characteristic of colicky pain (the pain is sometimes referred to as renal colic). It may be so severe that it is often accompanied by
nausea and vomiting. Kidney stones also characteristically cause blood in the urine. If infection is present in the urinary tract along with the stones, there may be
fever and
chills. Sometimes, symptoms such as difficulty urinating, urinary urgency, penile pain, or
testicular pain may occur due to kidney stones.
How are kidney stones diagnosed?
The diagnosis of kidney stones is suspected by the typical pattern of symptoms when other possible causes of the abdominal or flank pain are excluded. Imaging tests are usually done to confirm the diagnosis. A
helical CT scan without contrast material is the most common test to detect stones or obstruction within the urinary tract. Formerly, an
intravenous pyelogram (IVP; an X-ray of the abdomen along with the administration of contrast dye into the bloodstream) was the test most commonly used to detect urinary tract stones, but this test has a greater risk of complications, takes longer, and involves higher radiation exposure than the non-contrasted helical
CT scan. Helical CT scans have been shown to be a significantly more effective diagnostic tool than the IVP in the diagnosis of kidney or urinary tract stones.
In
pregnant women or those who should avoid radiation exposure, an
ultrasound examination may be done to help establish the diagnosis.
Treatment for kidney stones? How long does it take to pass a kidney stone?
Most kidney stones eventually pass through the urinary tract on their own within 48 hours, with ample fluid intake. Ketorolac (Toradol), an injectable anti-inflammatory drug, and narcotics may be used for pain control when over-the-counter pain-control medications are not effective. Intravenous pain medications can be given when
nausea and vomiting are present.
Although there are no proven home remedies to dissolve kidney stones, home treatment may be considered for patients who have a known history of kidney stones. Since most kidney stones, given time, will pass through the ureter to the bladder on their own, treatment is directed toward control of symptoms. Home care in this case includes the consumption of plenty of fluids.
Ibuprofen (Advil) may be used as an anti-inflammatory medication if there is no contraindication to its use. If further pain medication is needed, stronger narcotic pain medications may be recommended.
There are several factors which influence the ability to pass a stone. These include the size of the person, prior stone passage, prostate enlargement,
pregnancy, and the size of the stone. A 4 mm stone has an 80% chance of passage while a 5 mm stone has a 20% chance. Stones larger than 9 mm-10 mm rarely pass without specific treatment.
Some medications have been used to increase the passage rates of kidney stones. These include
calcium channel blockers such as
nifedipine (Adalat, Procardia, Afeditab, Nifediac) and alpha blockers such as
tamsulosin (Flomax). These drugs may be prescribed to some people who have stones that do not rapidly pass through the urinary tract.
For kidney stones that do not pass on their own, a procedure called
lithotripsy is often used. In this procedure, shock waves are used to break up a large stone into smaller pieces that can then pass through the urinary system.
Surgical techniques have also been developed to remove kidney stones when other treatment methods are not effective. This may be done through a small incision in the skin (percutaneous nephrolithotomy) or through an instrument known as an
ureteroscope passed through the
urethra and
bladder up into the
ureter.