Learn the facts about PKD – Polycystic Kidney Disease
Polycystic kidney disease is characterised by cysts in the kidney which increase both in size and number, often resulting in kidney failure. There are several different types of the condition (an adult form and an infantile form), each with a different genetic basis, inheritance pattern and different clinical features. While the infantile form (ARPKD) is extremely rare, the adult form (ADPKD) is very common with variable age of onset.
At a Glance:
What are cysts?
A cyst is a sac-like structure of tissue that may be filled with air, fluid or other substances like pus. A cyst may grow in almost any part or structure of the body or beneath the skin. Cysts may be of different types and most of them are benign i.e noncancerous. Sometimes cysts grow in the deeper structures of the body where they can’t be felt, however, they may at some stage cause symptoms. For example, cysts that result from the ovary lead to a condition called polycystic ovary syndrome (PCOS) with symptoms pertaining to ovarian and reproductive function. Similarly, cysts within the kidney cause a condition called Polycystic kidney disease (PKD), that may adversely affect kidney function.
In general, the decision pertaining to whether a cyst should be treated depends on factors, like:
- Location of the cyst
- Presence of infection
- Presence of symptoms like pain or discomfort
- Type of cyst
What is polycystic kidney disease (PKD)?
Polycystic kidney disease (PKD) is a genetic disorder which is inherited from one generation to another in the family. In PKD, the cysts originate from tiny filters in the kidneys, called nephrons. A kidney enlarges in size and weigh up to 30 pounds due formation of a cluster of cysts. Such cysts interfere with the normal activity of the kidney to filter waste from the body & eventually result in chronic kidney disease (CKD), kidney failure, or end-stage renal disease (ESRD).
What causes polycystic kidney disease (PKD)?
There are no external causes for PKD. People who have PKD are born with it. PKD is almost always inherited from a parent or from both parents to the offspring. It is mainly caused due to a mutation or an abnormal alteration in the genes named as PKD1, PKD2 and PKHD1. Those with an abnormal PKD1 and PKD2 will have an autosomal dominant PKD and those with abnormal PKHD1 will have an autosomal recessive PKD. It can present itself in any age group, gender, race, ethnicity or nationality. Men and women may get equally affected with PKD. If you have a blood relative with PKD, you are more likely to have PKD or carry the gene that causes it. If you carry the gene that causes PKD, but you do not have the disease, you are called a carrier. This is possible with autosomal recessive PKD.
Can polycystic kidney disease (PKD) be prevented?
If you have polycystic kidney disease and you’re considering having children, a genetic counselor can help you assess your risk of passing the disease to your offspring. A child with at least one parent having PKD has a very high chance of having PKD. While it is not possible to prevent the disease due to its genetic origin, maintaining a healthy lifestyle can help keep the kidneys working longer.
Keeping kidneys as healthy as possible may help prevent some of the complications of this disease.
- Take the prescribed blood pressure medications as directedby your doctor.
- Maintain a normal blood sugar level
- Eat a low-salt diet containing plenty of fruits, vegetables and whole grains.
- Maintain a healthy weight. Ask your doctor what is the right weight for you.
- Exercise regularly. Aim for at least 30 minutes of moderate physical activity most days of the week.
- If you smoke, quit.
- Limit alcohol use.
Is acquired cystic kidney disease a type of PKD?
Acquired cystic kidney disease is not genetic and occurs when cysts develop within the kidney over time. It is not the same as polycystic kidney disease (PKD), although there is cyst formation in both the conditions. Acquired cystic kidney disease occurs in children and adults having chronic kidney disease (CKD), a medical condition which occurs over a period of time, sometimes leading to end-stage kidney disease (ESRD) with total and permanent kidney failure. The ability of the kidneys to filter wastes, fluids and salts from the blood is gradually lost in CKD. People with end-stage kidney disease need a kidney transplant or dialysis for filtration of blood.
People who are on kidney dialysis are more likely to develop cysts and the chances increase with the years on dialysis. The cysts in such cases are attributed to CKD or kidney failure, not the dialysis treatments as such.
What causes autosomal dominant PKD?
Autosomal dominant PKD is caused by mutated genes, PKD1 and PKD2. Only one copy of the mutated gene is required to cause autosomal dominant PKD i.e only one parent with a mutated gene can cause autosomal dominant PKD. In very rare instances, a child may be born with autosomal dominant PKD genes even when neither of the parent has the mutated gene. However, this happens rarely in 1 out of 10 cases.
How will I know if I have autosomal dominant PKD?
In autosomal dominant PKD, most of the time the symptoms are not visible until the age of 30 to 40 years. The most common signs and symptoms include;
- Back and side pain
- Blood in urine
- Bloated stomach
- Frequent kidney and urinary tract infections
- High blood pressure
- Kidney stones
Some of the diagnostic tests that are indicative of autosomal dominant PKD include;
- Imaging tests
- Computed tomography (CT) scan
- Magnetic resonance imaging (MRI)
- Genetic test, a blood test to check the abnormal gene
What are the complications of autosomal dominant PKD?
People with autosomal dominant kidney disease may face complications which include but not limited to;
- Aneurysms in the brain
- Chronic back and side pain
- Colon problems
- Complications during pregnancy
- The growth of cysts in the liver and pancreas
- High blood pressure
- Kidney and liver failure
- Kidney stones
- Problems in the valve of the heart
What causes autosomal recessive PKD?
Like autosomal dominant PKD, autosomal recessive PKD is also an inherited disease and is caused by a mutated gene, PKHD1. However, in the case of autosomal recessive PKD, both parents must be carriers of the gene for a child to have the disease.
How does one know that an individual is a carrier?
If the child’s parents are carriers of PKHD1 but the child does not show any signs and symptoms of autosomal recessive PKD, there is a great chance of the child being a carrier. One can confirm being a carrier of the gene by undertaking a genetic test, wherein the blood or saliva sample is collected and tested for the presence of the PKHD1 gene. If the test gives a positive result of the gene but does not show any signs and symptoms of the disease then it confirms that the person is a carrier.
How will I know if my child has autosomal recessive PKD?
Signs of an unborn child having autosomal kidney disease include the appearance of the baby’s kidney to be larger than the normal size, and lack of amniotic fluid in the womb in the ultrasound examination of the pregnant mother.
Signs and symptoms of a baby that are born with autosomal recessive PKD include:
- Bloated stomach
- High blood pressure
- Insufficient growth of the body
- Pain in the back and side
- Urinary tract infection
- Varicose veins
- Vomiting of breast milk
What are the complications of autosomal recessive PKD?
A child that is born with autosomal recessive PKD may not survive for long. Sometimes those with very severe autosomal recessive PKD may survive only for hours or days after being born. Sometimes, children diagnosed with ARPKD may not survive till their first month of being born and few may live for almost 10 years after birth but may face certain complications that worsen with time. Some of these include;
- Frequent urinary tract infection
- Liver and kidney failure before adolescence
- Very high blood pressure
Is it possible to completely cure polycystic kidney disease?
Polycystic kidney disease cannot be completely cured or prevented. However, research is still in progress to help prolong the life and improve the quality of life of a person with PKD. Studies have also suggested that drinking sufficient amount of water can slow down the growth of cysts in the kidneys.
What are the methods of kidney cyst removal?
Kidney cysts that affect kidney function, may undergo the following options of treatment;
- Surgery to remove kidney cysts
- Puncturing and draining of fluid from the cysts and then filling with alcohol to shrink the cysts
What is the treatment for autosomal recessive PKD?
At present, autosomal recessive PKD cannot be treated. Only symptomatic treatment may be carried out, which include;
- Regulation of high blood pressure.Blood pressure controlling medications and regular monitoring of blood pressure
- Pain management with painkiller medications
- Kidney and bladder infections – Proper intake of antibiotics to cure infections.
- Blood in urine (hematuria) – A lot of plain water intake
- Kidney failure – Dialysis and kidney transplant are the methods of treatment for kidney failure
Does a kidney transplant cure PKD?
Kidney transplant has shown successful results, however, the patient continues to stay on prescription medicines and precautionary measures. A person with a kidney transplant must take regular immunosuppressant drugs to avoid the rejection of the new kidney in the body. This inturn also increases the risk of infections. Therefore, special care should be taken to avoid even a simple cold as this might lead to a serious health issue.
What is the life expectancy for an individual with polycystic kidney disease?
Autosomal dominant PKD is a progressive disease. The likelihood of requiring dialysis is estimated at less than 2% in people under age 40, increasing to 50 to 75% by age 70 to 75. By the age of 60, half of all patients require dialysis or transplantation, with kidney failure occurring at an average age of 74 years for PKD2 patients & 55 years for PKD1 patients. The life expectancy for PKD1 patients is 53.0 years and 69.1 years for PKD2 patients.
The incidence of polycystic kidney disease (PKD) is increasing over the years in various age groups. Both autosomal dominant PKD and autosomal recessive PKD are conditions with severely associated morbidity and mortality. Researches have been taking place to find out measures to cure PKD and to reduce the progression of the disease. Kidney transplant has shown successful result but precautionary measures are to be taken to cope up with its complications.
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