Polycystic kidney disease

Overview

Polycystic kidney disease (PKD) affects thousands in the United States and millions globally, yet it is still mostly unknown. Polycystic kidney disease causes many cysts to form in the kidneys. These cysts are filled with fluid. The kidneys might be harmed if too many cysts form or grow too large. PKD cysts can gradually replace most of the kidneys, lowering kidney function and eventually leading to renal failure. 

 

What is polycystic kidney disease?

Polycystic kidney disease is a multisystem, progressive illness characterized by cyst development and kidney enlargement, as well as involvement of other organs (e.g., liver, pancreas, spleen). It is the most common hereditary cause of renal failure in adults, accounting for 6% to 8% of dialysis patients in the United States. By the age of 60, half of them require renal replacement therapy. Cysts can be seen in children or in utero, although clinical signs do not show until the third or fourth decade of life.

 

How Common is PKD?

PKD affects around 600,000 persons in the United States. It is the fourth most common cause of renal failure. It is common in all ethnicities and affects both men and women equally. It accounts for around 5% of all renal failure.

 

Polycystic kidney disease (PKD) Causes 

Polycystic kidney disease is caused by a number of genetic abnormalities. Some are caused by dominant genes, while others are caused by recessive genes. That is, a person with the condition has one copy of a dominant gene from one parent or two copies of a recessive gene from each parent. People with dominant gene inheritance frequently do not exhibit symptoms until they reach maturity. Children with recessive gene inheritance suffer from serious illnesses.

The genetic abnormality causes extensive cyst development in the kidneys. Gradual cyst growth with aging is accompanied by decreased blood supply and scarring within the kidneys. Cysts can bleed or get infected. Kidney stones can form. Chronic renal disease can develop over time. Cysts in other regions of the body, such as the liver and pancreas, may develop as a result of the genetic abnormality.

 

What Happens to the Kidneys in PKD?

In the kidneys, many cysts form. A cyst is a tiny circular ball of fluid filled with water. Their sizes range from a pinhead to a table tennis ball (2cm). Each cyst is formed by the inflating of small tubes located in the kidneys. The kidneys may eventually become quite big, like a mass of tiny balls glued together. This is not a cancerous or malignant alteration. They can be three to four times the size of typical kidneys.

Kidney failure is common in late middle age. However, in some families, renal failure is delayed or never happens, whereas in others, kidney failure develops sooner (age 40-45 years)

Normally, the function deteriorates gradually, but blood tests can forecast how long the kidneys will work. Dialysis may be required if renal failure arises, and a kidney transplant should be possible.

 

Types of Polycystic kidney disease

The two major inherited forms of polycystic kidney disease are:

• Autosomal dominant PKD
• Autosomal recessive PKD.

 

Autosomal dominant PKD

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent hereditary type of polycystic kidney disease. A parent with autosomal dominant PKD has a 50% probability of passing on the changed gene (PKD1 or PKD2) and related disease to each of their offspring.

When there is no family history of the disorder, a person may develop it. It is suspected that a different inheritance pattern or a genetic alteration is to blame. As with hereditary PKD, the afflicted individual has a 50% risk of passing on the mutated gene and the accompanying disease to each of their offspring. Kidney failure can result from autosomal dominant PKD.

 

Autosomal recessive PKD

Autosomal recessive polycystic kidney disease (PKD) is a less prevalent genetic type of polycystic kidney disease. The symptoms appear in the first few months of life, or even while the infant is still growing in the uterus.

Autosomal recessive PKD is sometimes known as 'infantile PKD.' Children with autosomal recessive PKD frequently suffer kidney failure within a few years after birth and develop liver issues as adults.

 

Symptoms of PKD

Renal size rises with age, and renal enlargement occurs in 100 percent of PKD patients. Pain, hematuria, hypertension, and renal impairment are all associated with the degree of the structural abnormalities. The majority of clinical symptoms are caused by the enlargement of renal cysts.

Acute renal discomfort is fairly common as a result of cyst bleeding, infection, stone, and, in rare cases, malignancies. Visible hematuria may be the first sign to appear. When the cyst connects with the collecting system, a common consequence that causes gross hematuria is cyst hemorrhage. It can cause a fever, enhancing the risk of cyst infection. A hemorrhagic cyst will occasionally burst, resulting in a retroperitoneal hemorrhage.

Urinary tract infection (UTI) is prevalent in people with Parkinson's disease. Cystitis, acute pyelonephritis, cyst infection, and perinephric abscesses are all symptoms of UTI. The majority of infections are caused by E. coli, Klebsiella and Proteus species, as well as other Enterobacteriaceae. CT and MRI are both capable of detecting complex cysts.

Renal stone disease affects around 20% of PKD patients. The majority of stones are made up of uric acid, calcium oxalate, or both. Stones in PKD might be difficult to detect on imaging due to cyst wall and parenchymal calcification. CT urography is beneficial.

The most prevalent PKD symptom is hypertension. In hypertensive individuals with PKD, microalbuminuria, proteinuria, and hematuria are more prevalent.

Renal function is normal in the vast majority of individuals. When renal function begins to deteriorate, the kidneys are generally significantly enlarged. ESRD is not a foregone conclusion in PKD. At the age of 50, up to 77 percent of patients had retained renal function, and 52 percent at the age of 73. The volumes of the kidneys and cysts are the best indicators of renal functional deterioration.

Most simple hepatic cysts are solitary, and PLD should be considered if there are four or more cysts in the hepatic parenchyma.

 

Does everyone with PKD develop kidney failure?

No. Approximately 50% of patients with PKD will have kidney failure by the age of 60, and 60% will have kidney failure by the age of 70. Dialysis or a kidney transplant will be required for those who have renal failure. Certain persons are predisposed to kidney failure, including:

• Men
• Patients with high blood pressure
• Patients with protein or blood in their urine
• Women with high blood pressure who have had more than three pregnancies

 

Diagnosis of PKD

The severe symptoms of autosomal recessive PKD (ADPKD) frequently precipitate a diagnosis. However, in the majority of instances of autosomal dominant PKD, there are no symptoms for many years.

Physical examinations and blood and urine tests may not always detect the condition. It is frequently discovered during medical examinations for other health issues, such as urinary tract infections. Occasionally, the condition is not detected until the kidneys begin to fail.

Diagnosis of PKD may involve a number of tests including:

• Physical examination – can detect symptoms such as high blood pressure or enlarged kidneys
• Blood tests – to assess kidney function
• Urine tests – blood or protein (or both) may be found in the urine
• Ultrasound – a simple, non-invasive test that can identify even quite small cysts
• Genetic testing – this is not a routine test but may be used for family testing. The presence of the abnormal genetic material can be detected with special blood tests. Genetic counselling is available for affected couples.

 

Management

• Flank Pain: 

Infection, stone, and tumor should be ruled out as possible causes of flank discomfort. Opioid analgesics should only be used to treat severe pain. Reassurance, lifestyle changes, and avoiding irritating activities may be beneficial. Tricyclic antidepressants are useful in chronic pain syndromes because they are well tolerated. If it is determined that a big cyst is causing the pain, cyst aspiration can be performed under ultrasound or CT guidance. If many cysts are causing discomfort, laparoscopic or surgical cyst fenestration may be beneficial.

• Cyst hemorrhage: 

Cyst hemorrhage episodes are self-limiting, and patients react well to conservative therapy, which includes bed rest, painkillers, and increased fluid intake to prevent clots from blocking blood vessels. In rare cases, the bleeding is significant enough to cause hemodynamic instability, necessitating hospitalization and transfusions.

• Cyst and urinary tract infection:

To avoid retrograde seeding of the renal parenchyma, symptomatic cystitis and asymptomatic bacteriuria should be treated as soon as possible. Trimethoprim-sulfamethoxazole and fluoroquinolones are preferred agents. Infected cysts should be drained percutaneously or surgically if fever persists after 1 to 2 weeks of proper antimicrobial treatment. Nephrectomy should be explored in the event of end-stage polycystic kidney disease.

• Nephrolithiasis:

Potassium citrate is the preferred therapy for stone-forming problems such as uric acid stones, calcium oxalate stones, and distal acidification disorders.

• Hypertension:

In ADPKD, angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) enhance renal blood flow and are the preferred antihypertensives.

 

Dietary Management

Diet management is one method of delaying the course of PKD. Many persons with the condition control it by eating a low salt, low protein diet and drinking enough of water. A person with chronic renal disease may undergo laboratory testing to discover which nutrients are and are not being adequately digested. With this knowledge, the individual may decide to consult with a renal dietitian to discuss a specialized diet tailored to the individual's needs.

Fluid consumption is also vital in the treatment of PKD and should be reviewed with a nephrologist. Early in the illness process, people with PKD lose their capacity to absorb water efficiently. As a result, a person with PKD may become dehydrated easily after hard exertion or high heat. Dialysis patients must also keep track of their fluid intake based on the volume of urine generated and the type of dialysis they are receiving. Fluid consumption should be limited to 1 liter per day if the person is no longer urinating.

 

Can cysts be removed or operated on?

Cysts seldom need draining. If so, a needle with some local anaesthetic to lessen the pain and an X-ray (ultrasound) equipment for guiding can be used. However, because polycystic kidneys have so many cysts, draining of a single cyst would not heal the problem. Even if one cyst is unpleasant, each kidney may have hundreds of cysts, and needling the one causing the problem might be difficult. Despite the fact that cyst draining is still in its early stages, it can occasionally be beneficial.

In extreme circumstances, especially if serious infection has been a concern, the entire kidney can be removed during surgery. Because the kidney is frequently enlarged, this is not a trivial procedure, although it can be quite beneficial in some cases. In rare circumstances, the kidney is so big that it would be difficult to implant a donated kidney, hence a polycystic kidney must be removed before being placed on the transplant list.

 

Should a family member be Screened for Polycystic Disease?

An ultrasonic (sound wave) scan of the kidneys is used as a screening test. This is a straightforward and painless procedure. Prenatal ultrasounds of a fetus may reveal cysts in the kidneys. Even if only a few cysts are seen, this strongly suggests ADPKD in the infant if the mother also has ADPKD.

Until recently, children were not checked for ADPKD. This was largely due to the fact that cysts in the kidneys may not be discovered until someone is 25-30 years old, and doctors did not want to induce concern by diagnosing a child with ADPKD if there was no therapy available. 

First, new ultrasound equipment may identify microscopic cysts in the kidney, which may be seen in many youngsters, increasing the certainty of the diagnosis. Second, there is growing focus on the management of high blood pressure in children with renal disease, suggesting that early detection may provide significant long-term benefit.

Exact advice varies by region but many experts recommend undergoing an ultrasound scan of the kidneys in children at risk between the ages of 7 and 10, then repeating every 5 years until the age of 30 if cysts are not found.

CT scan is not required, and many people choose not to get one. Even if a scan is not conducted, it may be advisable to have your blood pressure checked on a regular basis. Some persons at risk of ADPKD believe that skipping the scan will save them money on life and health insurance. This is not true. In fact, the situation is precisely the opposite; if someone conceals the potential of ADPKD from an insurance provider, they risk having all of their policy cancelled.

 

Should women with PKD get pregnant?

The majority of women with PKD (80%) have successful and uncomplicated pregnancies. However, certain PKD mothers are at a higher risk of catastrophic consequences for themselves and their newborns. This includes PKD ladies who additionally have:

• High blood pressure
• Decreased kidney function

In 40% of pregnancies, women with PKD and high blood pressure suffer pre-eclampsia (or toxemia). This is a life-threatening illness that can strike both the mother and the baby at any time. As a result, all women with PKD, particularly those with high blood pressure, should be continuously monitored by their doctor during their pregnancy. 

 

What are Complications of PKD?

• Pain in the kidneys might arise as a result of an infection or a tiny bleed into a cyst. Typically, basic pain relievers will address the symptoms, which should improve in a few days. A urine sample may be required to determine the presence of an infection.
• Occasionally, bleeding into a cyst might result in blood in the urine.
• When renal illness is detected, there may be cysts in the liver that can be observed on an ultrasound scan. It is extremely rare for these to induce liver failure.
• High blood pressure is frequent and should be addressed as soon as possible to protect the kidneys and the rest of the circulation from potential injury. Even if the kidney function is normal at this time, blood pressure should be tested every 6-12 months.
• Stroke is an uncommon complication of APCKD. This emphasizes the need of maintaining proper blood pressure regulation. Discuss this with your doctor if any members of your family with polycystic illness have suffered an early stroke.
• Diverticulae are outpouchings in the wall of the large bowel. These are quite frequent in the general population and are rarely a cause for concern. They can induce gastrointestinal irregularities and pain (diarrhea and constipation). Diverticular disease is not a kind of bowel cancer and does not cause it.

 

Can People with PKD lead a normal life?

With this illness, it is typically feasible to lead a regular active life. Until kidney failure is advanced, there are usually no signs. Dialysis and transplantation should allow you to continue working and doing the majority of the activities you wish to do. Other individuals, however, experience painful kidneys at times, which might limit hard labor and some regular tasks.

When applying for mortgages or life insurance, the condition must be disclosed. Nowadays, it should still be feasible to obtain coverage in the traditional manner, however the policy may need to be loaded. The insurance company may want extra medical records, so plan on a slight wait if any policies are required. If one firm refuses you, try again, and contact the National Kidney Federation for recommendations on helpful companies. 

 

Conclusion  

Polycystic kidney disease (PKD) is a hereditary renal cystic illness, the most prevalent type of which is autosomal-dominant polycystic kidney disease. Key clinicians needed to care these patients include a nephrologist, surgeon, invasive radiologist, neurosurgeon, cardiologist, and a nephrology or dialysis nurse.