Autosomal dominant PKD
is one of the most common
inherited disorders. The phrase "autosomal dominant" means that if
one parent has the disease, there is a 50-percent chance that the
disease will pass to a child. At least one parent must have the
disease for a child to inherit it. Either the mother or father can
pass it along, but new mutations may account for one-fourth of new
cases. In some rare cases, the cause of autosomal dominant PKD
occurs spontaneously in the child soon after conception--in these
cases the parents are not the source of this disease.
Many people with autosomal dominant PKD live for decades without
developing symptoms. For this reason, autosomal dominant PKD is
often called "adult polycystic kidney disease." Yet, in some cases,
cysts may form earlier, even in the first years of life.
The disease is thought to occur equally in men and women and
equally in people of all races. However, some studies suggest that
it occurs more often in whites than in blacks and more often in
females than in males. High blood pressure occurs early in the
disease, often before cysts appear.
The cysts grow out of nephrons, the tiny filtering units inside
the kidneys. The cysts eventually separate from the nephrons and
continue to enlarge. The kidneys enlarge along with the cysts
(which can number in the thousands), while retaining roughly their
kidney shape. In fully developed PKD, a cyst-filled kidney can
weigh as much as 22 pounds.
What are the symptoms of autosomal dominant
The most common symptoms are pain in the back and the sides
(between the ribs and hips), and headaches. The dull pain can be
temporary or persistent, mild or severe.
People with autosomal dominant PKD also can experience the
Urinary tract infections
Hematuria (blood in the urine)
Liver and pancreatic cysts
Abnormal heart valves
High blood pressure
Aneurysms (bulges in the walls of blood vessels) in the
Diverticulosis (small sacs on the colon).
How is autosomal dominant PKD diagnosed?
To diagnose autosomal dominant PKD, a doctor typically observes
three or more kidney cysts using ultrasound imaging. The diagnosis
is strengthened by a family history of autosomal dominant PKD and
the presence of cysts in other organs.
In most cases of autosomal dominant PKD, the person's physical
condition appears normal for many years, even decades, so the
disease can go unnoticed. Physical checkups and blood and urine
tests may not lead to diagnosis. The slow, undetected progression
is why some people live for many years without knowing they have
autosomal dominant PKD.
Once cysts have formed, however, diagnosis is possible with
imaging technology. Ultrasound, which passes sound waves through
the body to create a picture of the kidneys, is used most often.
Ultrasound imaging employs no injected dyes or radiation and is
safe for all patients including pregnant women. It can also detect
cysts in the kidneys of a fetus.
More powerful and expensive imaging methods such as computed
tomography (CT scan) and magnetic resonance imaging (MRI) also can
detect cysts, but these methods usually are not required because
ultrasound provides adequate information. CT scans require x-rays
and sometimes injected dyes.
In the future, DNA testing will be able to confirm a diagnosis
of autosomal dominant PKD before cysts develop.
How is autosomal dominant PKD treated?
Although a cure for autosomal dominant PKD is not available,
treatment can ease the symptoms and prolong life.
A doctor will first suggest over-the-counter pain
medications, such as aspirin or Tylenol. For most but not all cases
of severe pain, surgery to shrink cysts can relieve pain in the
back and flanks. However, surgery provides only temporary relief
and does not slow the disease's progression, in many cases, toward
Headaches that are severe or that seem to feel different from
other headaches might be caused by aneurysms, or swollen blood
vessels, in the brain. Headaches also can be caused by high blood
pressure. People with autosomal dominant PKD should see a doctor if
they have severe or recurring headaches-even before considering
over-the-counter pain medications.
Urinary Tract Infections.
Patients with autosomal
dominant PKD tend to have frequent urinary tract infections, which
can be treated with antibiotics. People with the disease should
seek treatment for urinary tract infections immediately, because
infection can spread from the urinary tract to the cysts in the
kidneys. Cyst infections are difficult to treat because many
antibiotics do not penetrate into the cysts. However, some
antibiotics are effective.
High Blood Pressure.
Keeping blood pressure under control
can slow the effects of autosomal dominant PKD. Lifestyle changes
and various medications can lower high blood pressure. Patients
should ask their doctors about such treatments. Sometimes proper
diet and exercise are enough to keep blood pressure low.
End Stage Renal Disease.
Because kidneys are essential for life, people with ESRD must seek
one of two options for replacing kidney functions: dialysis or
transplantation. In hemodialysis, blood is circulated into an
external machine, where it is cleaned before reentering the body;
in peritoneal dialysis, a fluid is introduced into the abdomen,
where it absorbs wastes, and it is then removed. Transplantation of
healthy kidneys into ESRD patients has become a common and
successful procedure. Healthy (non-PKD) kidneys transplanted into
PKD patients do not develop cysts.
Genes are segments of DNA, the long molecules that reside in the
nuclei of your body's cells. The genes, through complex processes,
cause chemical activities that lead to growth and maintenance of
the body. At conception, DNA (and therefore genes) from both
parents are passed to the child.
A genetic disease occurs when one or both parents pass abnormal
genes to a child at conception. If receiving an abnormal gene from
just one parent is enough to produce a disease in the child, the
disease is said to have dominant inheritance. If receiving abnormal
genes from both parents is needed to produce disease in the child,
the disease is said to be recessive.
The chance of acquiring a dominant disease (one gene copy is
enough) is higher than the chance of acquiring a recessive disease
(two gene copies are needed). A child who receives only one gene
copy for a recessive disease at conception will not develop the
genetic disease (such as autosomal recessive PKD), but could pass
the gene to the following generation.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a