Incidence, Symptoms and Diagnosis
Autosomal dominant polycystic kidney disease (ADPKD) is the most
common genetic or inherited disease of the kidney, characterized by
the growth of numerous cysts in the kidneys. Polycystic kidney disease
(PKD) is the fourth leading cause of chronic kidney disease. In PKD,
other organs in which cysts can be seen are the liver, brain, intestines,
pancreas, ovaries and spleen.
What is the incidence of PKD?
The incidence of
PKD is the same in all
races, occurs equally in
males and females and
affects about 1 in 1,000
About 5% of all chronic
kidney disease patients
requiring dialysis or
How is the kidney affected in PKD?
In autosomal dominant PKD multiple clusters of cysts (fluid-filled
sacs) are seen in both kidneys.
Sizes of cysts in PKD are variable (diameter ranging from a pinhead to as large 10 cm. or more). With time cysts increase in size and slowly compress and damage
healthy kidney tissue.
Such damage leads to hypertension, loss of protein in urine and
reduction in kidney function, causing chronic kidney failure.
In a long period (after years) chronic kidney failure worsens and
leads to severe kidney failure (endstage kidney disease), ultimately
requiring dialysis or kidney transplantation.
Symptoms of PKD
Many people with autosomal dominant PKD live for several decades
without developing symptoms. Most patients with PKD develop
symptoms after the age of 30 to 40 years. Common symptoms of PKD
- High blood pressure.
- Pain in the back, flank pain on one or both sides and/or a swollen
- Feeling a large mass (lump) in abdomen.
- Blood or protein in urine.
- Recurrent urinary tract infections and kidney stones.
- Symptoms of chronic kidney disease due to progressive loss of kidney
- Symptoms due to cysts in other parts of the body such as the brain,
- Complications that can occur in a patient with PKD are
brain aneurysm, abdominal wall hernias, infection of liver cysts,
diverticulae (pouches) in the colon and heart valve abnormalities.
About 10% of PKD patients develop a brain aneurysm. An aneurysm is a weakeningof the wall of the blood vessel which causes bulging. Brain aneurysms can cause headaches and carry a small risk of rupture that can lead to a stroke or even death.
PKD is the most commonly inherited kidney disease
and among the leading causes of CKD.
Does everyone with PKD develop kidney failure?
No. Kidney failure does not occur in all patients with PKD. About 50
% of patients with PKD will have kidney failure by the age of 60, and
about 60 % will have kidney failure by the age of 70. The risk factors
for progression of CKD in patients with PKD include: larger renal size,
younger age at diagnosis, hypertension (particularly before age 35 years),
proteinuria (> 300 mgs/day), gross hematuria, male gender, > 3
pregnancies, certain genetic mutations (PKD1 gene mutation), as well
as tobacco consumption.
Diagnosis of PKD
Diagnostic tests performed in autosomal dominant PKD are:
- Ultrasound of the kidneys. This is the most commonly used
diagnostic test for PKD because it is reliable, simple, safe, painless,
less costly, and easily identifies cysts in the kidneys.
- CT or MRI scans: These tests are more precise but are expensive.
These tests may detect smaller cysts that cannot be diagnosed by an
- Family screening: PKD is an inherited disease in which each child
has a 50:50 chance of developing the disease. So screening of family
members of a patient with PKD helps in early diagnosis.
- Tests to assess effect of PKD on kidney: Urine test is done to
detect the presence of blood or protein in urine. Blood test for
creatinine is done to assess and monitor the function of the kidney.
Which family members of PKD patients should be screened
- Incidental diagnosis: PKD detected in routine health check up or
during ultrasound examination done for another reason.
- Gene linkage analysis: This is a very specialized blood test, used
to detect which family member carries the PKD gene. This test should
be done only if imaging tests do not show anything. As this test is
available in very few centers and is very expensive, it is done rarely
for diagnostic purposes.
Brothers, sisters and children of PKD patients should be screened for
PKD. In addition, brothers and sisters of parents from whom the disease
is inherited by the patient should be screened.
Will all children of PKD patients carry the risk of developing
the same disease?
No. PKD is an inherited disease in which if mother or father has autosomal
dominant PKD, the children have a 50% possibility of developing the
Flank and abdominal pain and blood in urine at the
age of 40 is the most common presentation of PKD.
Prevention and Treatment
Prevention of PKD
Currently there is no treatment that can prevent formation or slow down
the growth of cysts in PKD.
Screening of family members and making an early diagnosis before it
sets in has several advantages. Early diagnosis provides an opportunity
to treat PKD in a better way. Early diagnosis and treatment of high
blood pressure prevents development or aggravation of renal failure in
PKD. Lifestyle and dietary modification in PKD patients protects their
kidney as well as the heart. The major disadvantage of screening is that
the person may become very anxious about the disease at a stage when
the person neither has the symptoms nor needs any treatment.
PKD is an inherited kidney disease so consider
screening of adult family members for PKD.
Why is it not possible to reduce the incidence of PKD?
PKD is diagnosed usually at the age of 40 years or more. Most people
have children before this age and therefore it is not possible to prevent
its transmission to the next generation.
Treatment of PKD
PKD is a non-curable disease but why does it need treatment?
- To protect the kidneys and delay progression of chronic kidney
disease to end stage kidney disease and thereby prolong survival.
- To control the symptoms and prevent complications.
Important measures in the treatment of PKD:
- The patient is asymptomatic for many years after initial diagnosis
and does not require any treatment. Such patients need periodic
checkup and monitoring.
- Strict control of high blood pressure will slow down the progression
- Control of pain with drugs which will not harm the kidney (such as
aspirin or acetaminophen). Recurrent or chronic pain occurs in PKD
due to cyst expansion.
- Prompt and adequate treatment of urinary tract infections with
- Early treatment of kidney stones.
- Plenty of fluid intake, provided the person does not have swelling
helps in prevention of urinary tract infections and kidney stones.
- Meticulous treatment of chronic kidney disease as discussed in
Chapters 10 to 14.
- In a very few patients surgical or radiologic drainage of cysts may
be indicated because of pain, bleeding, infection, or obstruction.
Treatment is aimed at delaying progression of CKD and
treating kidney infections, stones and abdominal pain.
When should a patient with PKD consult a doctor?
Patients with PKD should immediately consult a doctor if he or she
- Fever, sudden abdominal pain or red urine.
- Severe or recurrent headaches.
- Accidental injury to enlarged kidneys.
- Chest pain, severe loss of appetite, severe vomiting, severe muscle
weakness, confusion, drowsiness, unconsciousness or convulsion.
Asymptomatic person with PKD may not require
any treatment for many years initially.