How Autosomal Dominant Polycystic Kidney Disease Is Diagnosed

Most people diagnosed with autosomal dominant polycystic kidney disease (ADPKD) are in middle adulthood, but the condition can start in childhood. ADPKD is a slow-developing condition, so symptoms usually aren’t noticeable until cysts grow large enough to affect renal (kidney) function.

This article will discuss how ADPKD is diagnosed, including self-checks, physical examination, labs, other tests, and differential diagnosis.

Self-Checks/At-Home Testing

It is not possible to diagnose ADPKD on your own. Knowing the signs to look for and letting your healthcare provider know your symptoms, however, can aid in diagnosis. This is especially important if ADPKD runs in your family.

Symptoms of ADPKD include:

• Abdominal pain
• Kidney pain in the back or side (called flank pain)
• Hypertension­ (high blood pressure)
• Hematuria (blood in the urine)
• Frequent and serious urinary tract infections (UTIs)
• Kidney stones
• Gradual kidney failure: Signs might include nausea and vomiting, loss of appetite and weight loss, frequent or decreased urination, muscle cramps, cognitive troubles, swelling of the ankles and feet, blood pressure that is difficult to manage, and shortness of breath.
• Fluttering or pounding of the chest: According to the Polycystic Kidney Disease Foundation, around 25% of people with PKD have a floppy heart valve and will experience fluttering or pounding of the chest and chest wall. These symptoms can disappear on their own, but they are early signs of PKD.

Many signs of early ADPKD tend to be nonspecific, meaning they also can be caused by other conditions. But because the kidneys cannot make up for lost function, there could be irreversible damage before you are even diagnosed.

Physical Examination

Physical examination for ADPKD involves observing physical changes in people with the condition.

For example, people with this condition experience pain and discomfort. Your doctor will look for signs of abdominal masses in the low back or bulging that indicate an enlarged kidney or liver. Flank pain and tenderness in the low back might also be felt when pressure is applied to areas of the abdomen and lower back closest to the kidneys.

Your doctor may also examine your skin for jaundice (yellowing of the skin) and pallor (pale skin). This is common in people who have liver cysts. Jaundice can also affect the white part of the eyes.

Edema (swelling) of the upper and lower extremities in ADPKD is a sign of kidney failure. You may also be asked about any bleeding in the urine and back or side pain you might be experiencing.

Your blood pressure will also be checked. One of the earliest signs of ADPKD is high blood pressure. It affects most people with ADPKD and is usually severe, eventually leading to kidney failure.

The higher a person's blood pressure (the force of blood against artery walls) is, the higher their risk is for certain health conditions, including heart disease, heart attack, and stroke. According to the Centers for Disease Control and Prevention (CDC), high blood pressure is a reading that is frequently above 130/80 millimeters of mercury (mm Hg).

Labs and Tests  

Lab tests can help your doctor to make a diagnosis of ADPKD, including urine and blood work, glomerular filtration rate testing, and genetic testing.

Urine and Blood Work

The earliest symptoms of ADPKD are usually flank pain and blood in the urine. Because these symptoms are found in other conditions, your doctor will want to start with urine tests and blood work.

Urine testing can check for blood or protein in the urine that might be related to proteins and enzymes in kidney cysts.

A glomerular filtration rate (GFR) blood test checks how the kidneys are working. Glomeruli are tiny filters in the kidneys that remove waste and extra fluid from the blood. The GFR test estimates how much blood passes through glomeruli per minute. It is the most reliable test of kidney function.

But urine and blood testing aren't enough to identify ADPKD, and your healthcare provider will want to do additional lab work and other tests to aid in diagnosis.

Genetic Testing

Genetic testing can detect mutations of the PKD1 and PKD2 genes, the genes responsible for causing ADPKD. PKD1 is found in 85% of people with the ADPKD, and PKD2 is responsible for 15% of cases. Genetic testing can detect gene mutations before cysts even develop.

Unfortunately, genetic testing cannot predict the onset of ADPKD or disease severity in people who develop the condition. There is also no way to prevent ADPKD. However, being aware of your genetic risk can help you delay future blood pressure issues.

Genetic testing for PDK1 and PDK2 is also an option for prenatal diagnosis and preimplantation genetic diagnosis (profiling embryos before in vitro fertilization). Genetic testing in these instances is not always recommended because ADPKD doesn’t develop until adulthood.

Genetic testing for ADPKD is either done using blood or saliva samples. The sample is then tested in a special lab to look for specific gene mutations. Test results may take days or weeks to be completed.

Imaging

Imaging studies, including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), can screen for ADPKD.

Ultrasound imaging can create images of the entire urinary tract or focus on the kidneys only. Your urinary tract includes your two kidneys, two ureters, a bladder, and a urethra. Ultrasound images can show cysts in the kidneys.

CT scans use X-rays and computer technology to create images of the urinary tract. With the help of contrast dye, CT scans can show more detailed images of kidney cysts than ultrasound.

MRI scans can give your healthcare provider specific measurements of kidney and cyst sizes and help them to monitor the growth of the kidney and cysts. Measuring kidney and cyst size can also help to track ADPKD progression.

With ADPKD, there is a potential risk for intracranial hemorrhage (brain bleed).  Your doctor may request additional imaging studies, including MRIs and CTs, to look for signs of intracranial hemorrhage, including the size of a bleed and whether clots have formed.

This is usually done in people who have experienced severe, frequent headaches that have not been resolved using over-the-counter (OTC) pain relievers and have a family history of ADPKD.

Differential Diagnosis

Not every health condition can be diagnosed with a simple test, and many conditions can cause similar symptoms. A differential diagnosis looks at all possible causes of symptoms. This involves different testing methods to rule out other conditions and determine whether more testing is needed.

For the most part, making a diagnosis of ADPKD usually involves confirming a family history of the condition. However, if there is no family history, ADPKD requires a careful review of symptoms and radiological evidence to make a diagnosis. There is no family history in 10%–25% of people with ADPKD.

Kidney cysts are also common in adults. They are more frequent as people age and usually do not cause harm. Because they don’t cause symptoms, cysts are usually discovered during imaging studies for other reasons.

Your doctor will also want to rule out other conditions that cause renal cysts and similar symptoms as those seen in ADPKD. Differential diagnosis of ADPKD may include:

• Polycystic liver disease: This rare disorder causes cysts to grow throughout the liver.
• Autosomal recessive polycystic kidney disease: This second type of PKD commonly affects children, is much rarer, and can be fatal.
• Tuberous sclerosis: This rare genetic condition causes benign tumors to grow on various organ systems.
• Von Hippel-Lindau (VHL) disease: This rare condition causes abnormal blood vessel growths that are either benign (noncancerous) or malignant (cancerous) tumors and cysts.
• Orofaciodigital syndrome type 1: This is a group of related disorders that affect the development of the oral cavity (mouth and teeth), facial features, and fingers and toes. It is sometimes linked to polycystic kidney disease.
• Nephronophthisis: This kidney disorder is characterized by inflammation and scarring of the kidneys.
• Bardet-Biedl syndrome: This genetic disease affects multiple body symptoms, including the kidneys.          
• Localized cystic disease: This type of cystic kidney disease is rare, nonprogressive, and does not run in families. It is characterized by benign (harmless) clusters of cysts.
• Medullary sponge kidney (MSK): This is a congenital (present at birth) disorder that causes small cysts on the tiny tubes of the kidneys or the collecting ducts. The cysts will affect urine flow and can eventually cause UTIs and kidney stones.

Summary

Autosomal dominant polycystic kidney disease is an inherited genetic condition passed from parent to child. It is diagnosed using different testing methods, including a complete patient and family history, imaging, blood work, and urine testing.

Symptoms of ADPKD usually start in adulthood, but the condition can be detected in childhood. Imaging can help detect small cysts and determine the extent the disease has had on the kidneys and other organs.

Genetic testing looks for mutations of the PKD1 and PKD2 genes, which can help confirm a diagnosis. But genetic testing, especially in children, cannot predict disease onset or later disease severity.

A Word From Verywell

Getting a diagnosis of autosomal dominant polycystic kidney disease can be scary, but this condition progresses very slowly. Symptoms will worsen with time, and people with the condition may develop kidney failure very late into adulthood and require dialysis or a kidney transplant.

However, ADPKD can be manageable for decades with medicine and healthy lifestyle choices, and some people may never experience kidney failure.

If ADPKD runs in your family and you start experiencing symptoms of the condition, reach out to your doctor. And if you are diagnosed with ADPKD, it is important to regularly follow up with your healthcare team to manage and reduce your risk for kidney problems and other complications of ADPKD.