Polycystic Kidney Disease: Symptoms, Causes, Treatment & Life Expectancy

Polycystic Kidney Disease (PKD) is a genetic disease characterized by cysts that form in the kidneys. These cysts are essentially fluid-filled sacs that progressively grow to produce enlarged kidneys. In effect, the disease interferes with normal function of the kidneys.
PKD affects millions of people worldwide and is considered one of the most prevalent hereditary disorders among those suffering from kidney disease. There is no known cure for polycystic kidney disease, but timely diagnosis and proper treatment can help slow the progress of the disease.

What is Polycystic Kidney Disease?

Polycystic kidney disease (PKD) is a genetic disorder in that a number of cysts form on the kidneys. These cysts are benign; however, a large number of them can cause the kidneys to become enlarged and impair the filtering process.
Over time, PKD can result in:

• Chronic kidney disease (CKD)
• High Blood Pressure
• Kidney failure
• Other systemic complications

Unlike simple kidney cysts, which may be part of the aging process, PKD cysts are progressive and genetic in origin.

Types of Polycystic Kidney Disease

PKD has two main types, which are classified depending on their genetic inheritance and age of onset.

1. Autosomal Dominant Polycystic Kidney Disease

The most common form is ADPKD, which accounts for 90% of all such cases.
Key Characteristics:

• Symptoms develop between ages 30-50
• Only one mutated gene from one parent is necessary
• Each offspring of an affected individual has a 50 percent probability of inheriting it
• Cysts enlarge over a period of decades

A diagnosis of ADPKD typically occurs in adulthood during the evaluation for high blood pressure or during the imaging for unrelated conditions.

2. Autosomal Recessive Polycystic Kidney

ARPKD is a rare disorder that most commonly manifests in infancy or early childhood.
Key characteristics:

• Both parents must be carriers of the mutated gene
• Often detected before or shortly after birth
• May cause severe kidney and liver problems

An early age ARPKD may be fatal in newborns with severe forms.

What Causes Polycystic Kidney Disease?

The cause of PKD is genetic mutations affecting particular genes responsible for cell growth in the kidney.

Gene Mutations Involved

• PKD1 gene (responsible for about 85% of ADPKD
• PKD2 gene (accounts for ~15%)
• PKHD1 gene (in ARPKD)
  

These mutations disrupt the signaling of the cell, which should be able to function but instead develops cysts.

Is Polycystic Kidney Disease Genetic?

Yes. PKD has a genetic cause. In autosomal dominant PKD, only one gene mutation causes the disease. In autosomal recessive PKD, two gene mutations cause the disease.

Genetic counseling is strongly recommended for families with a known history of PKD.

Polycystic Kidney Disease Symptoms

Symptoms vary depending on the type and stage of disease. In many cases, persons suffering from ADPKD may not experience symptoms until adulthood.

Common symptoms include:

• High blood pressure
  
• Back or side pain
  
• Enlarged abdomen
  
• Blood in the urine (hematuria)
  
• Frequent urinary tract infections
  
• Kidney stones
  
• Headaches
  
• Fatigue
  

In advanced stages, symptoms associated with kidney failure will be experienced:

• Swelling in legs and ankles
  
• Shortness of breath
  
• Nausea
  
• Reduced urine output
  

Complications of Polycystic Kidney Disease

However, PKD does not affect the kidneys alone. Since it is a systemic disease, there are chances of complications in other organs as well.

1. Chronic Kidney Disease (CKD)

The majority of individuals with ADPKD will develop CKD. It is estimated that 50-60% of individuals will develop ESRF by the time they reach

2. High Blood Pressure

Hypertension is usually the first sign of PKD. It hastens kidney damage if not treated.

3. Liver Cysts

Liver cysts are common among adult individuals with ADPKD. Although liver cysts are typically harmless, discomfort or enlarged liver might occur.

4. Brain Aneurysms

Some PKD sufferers may be at increased risk of developing aneurysms, which are weak areas in blood vessel walls in the brain, which can cause harm when they rupture.

5. Heart Valve Abnormalities

Mitral valve prolapse occurs more frequently in individuals with PKD.

6. Pregnancy Complications

Women suffering from PKD and hypertension may be more vulnerable during pregnancy.

Treatment Options for Polycystic Kidney Disease

While there is no cure for the disease, the focus of treatment is to slow its progression and control any complications.

1. Blood Pressure Control

Maintaining optimal blood pressure is critical.

Common medications:

• ACE inhibitors
  
• ARBs
  

Controlling blood pressure significantly reduces kidney damage progression.

2. Tolvaptan

Tolvaptan is an FDA-approved medication for slowing cyst growth in ADPKD.

It works by blocking vasopressin, a hormone involved in cyst development.

However, it requires monitoring due to potential liver side effects.

3. Pain Management

Chronic pain may result from enlarged kidneys or cyst rupture.

Management options include:

• Acetaminophen (preferred over NSAIDs)
  
• Cyst drainage in severe cases
  

NSAIDs should generally be avoided due to kidney stress.

4. Treating Infections

UTIs should be treated promptly to prevent complications.

5. Dialysis

When kidney failure occurs, dialysis removes waste and excess fluids.

6. Kidney Transplant

Kidney transplantation offers the best long-term outcome for end-stage PKD.