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Kidney
Stones
By
Talsk Research's Physician Group
Overview
Kidney
stones are small, hard crystalline particles that form in the kidney
or urinary tract (excretory system) through which extra fluids and
waste products are removed from the body in the form of urine. The
kidneys are two bean-shaped organs located below the ribs toward the
middle of the back, one on each side of the spine.
Kidney
stones also known as renal calculi are made up of various
combinations of chemicals. The most common type of stone contains
calcium, sometimes in combination with either oxalate or phosphate.
Chemicals like uric acid and amino acid cystine can also form stones
in the urinary tract. These chemicals are a part of a person’s
normal diet and constitute important parts of the body, such as bones
and muscles. When these stones are small, they pass through urine
unnoticed. However, if they are larger, they can result in sudden
severe pain in the back, abdomen, or groin area sometimes associated
with nausea and vomiting. Some larger stones can even block the flow
of urine. Discoloration of urine or flank blood in urine is also
common symptom. Most patients with kidney stones are treated
medically while surgical treatment is used to remove larger stones.
Risk
Factors
Family
history or personal history of kidney stones
Men are
more likely to develop kidney stones than women
People
with high body mass index, increased waist size increase the risk
Excessive
meat, calcium or sodium in the diet
Chronic
diseases such as diabetes and high blood pressure
Pregnancy
can increase the risk of stone formation due to slow movement of
the ureters
Specific
medications and medical conditions discussed below.
Causes
Persistently
high levels of uric acid in the blood which happens in patients with
conditions like gout, intestinal disorders leading to chronic
diarrhea increase the risk for uric acid stones.
Medical
conditions like hyperparathyroidism (which causes bones to lose
calcium in the urine) and renal tubular acidosis increases the risk
for calcium phosphate stones
Urinary
tract infections increase the risk for struvite stones
Cystinuria,
a genetic disorder, increases the chance of cystine stones.
Certain
medications (e.g. chemotherapy, drugs to treat HIV, excessive
vitamin D supplements)
Symptoms
Sudden,
excruciating cramping or colicky pain in the side of abdomen
Pain
radiating from hip to legs
Persistent
urge to urinate
Nausea
Vomiting
Discoloration
of urine or frank blood in urine
Fever
and chills (if there is infection)
Diagnosis
Detailed
history and physical exam
X ray of
the kidney and urinary tract
Microscopic
examination - the kidney stones obtained from the urine sample are
examined under a microscope to identify the substance forming the
stone and determine further tests
Blood
tests - to measure the levels of calcium, phosphate, uric acid,
urea, nitrogen, creatinine, parathyroid hormone levels
Lately
Helical CT scans are replacing intravenous
pyelograms in which
a special dye injected into the vein after which X-rays are taken as
the dye enters the kidneys and travels down the urinary tract to
check for any abnormalities
Magnetic
resonance imaging
Treatment
The main
aim of the treatment is to relieve symptoms and prevent further
recurrence of kidney stones. Treatment usually depends on the type of
stone and the severity of the symptoms.
Medical
Treatment
If
the stone is small, increasing the amount of liquids and managing
the diet may help pass the stone along with the urine without
requiring any other treatment.
For
severe pain, narcotic painkillers or non-steroidal anti-inflammatory
drugs may be prescribed
The
type of medicines prescribed usually depends on the type of stone.
Medications may include:
Allopurinol
(for uric acid stones)
Antibiotics
(for struvite stones) to prevent urinary infection
Diuretics
(to help remove excess fluids in the body)
Sodium
bicarbonate or sodium citrate (to make the urine more alkaline,
which may help in dissolving certain stones)
Surgical
Treatment
Surgery
may be needed if the stones are too large and may be blocking the
urinary tract. The types of surgical treatment may include:
Extracorporeal
shock-wave lithotripsy - method used to break down a large stone
into smaller stones with shock waves
Percutaneous
nephrolithotomy - a small opening in the back made to remove larger
stones through surgery
Standard
open surgery (nephrolithotomy) may be needed if other methods do not
work or if they are not feasible
Prevention
Persons
with history of kidney stones are recommended to increase their
intake of liquids to enable passing about 2.6 quarts (2.5 liters) of
urine a day
Dietary
recommendations for reducing the risk of calcium stone formation
include increasing fluid intake, restricting salt and protein intake
(choosing non-animal protein sources such as nuts and legumes) and
increasing potassium and phosphate intake
If there
is a tendency to form calcium oxalate stones, restricting foods rich
in oxalates such as rhubarb, beets, okra, spinach, swiss chard,
sweet potatoes, tea, chocolate, and soy products may help
Continue
eating calcium-rich foods, calcium supplements have to be used
cautiously. The calcium in the food does not increase the risk for
kidney stones; however, calcium supplements can increase the chance
of kidney stone formation.
Fiber-rich
foods may be beneficial, as some of them may contain compounds that
help protect against kidney stone formation
Uric
acid stones can be prevented by decreasing the intake of protein
while increasing fluid intake
Credits:
The
copyright to the image used above belongs to LifeART, Wolters Kluwer
Health, Inc.- Lippincott Williams & Wilkins. All rights reserved.
References
All
information provided above is for basic awareness and education
purposes only and should not be used for diagnosis or treatment of
any medical condition under any circumstance. Please consult a
licensed medical professional for these purposes. In case of medical
emergency please call 911.
Copyright
2011 Talsk Research Inc. All rights reserved.
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