Diagnosing PKD

Diagnosing Polycystic Kidney Disease

Many people with polycystic kidney disease (PKD) live a normal and healthy life up until early adulthood.  They may not notice any symptoms until they reach their 30s or 40s.  The first sign of PKD is often hypertension (high blood pressure) and pain in the side.

PKD can be best diagnosed through imaging.  This includes:

-Abdominal ultrasound
-CAT scan
-MRI

Ultrasound is typically used as it is cost effective and readily available.  Most cysts can be visualized using ultrasound.

An ultrasound is a non-invasive procedure that a doctor or other medical care worker will use to visualize an internal structure, in this case, the kidneys. In the following video, a patient who has had multiple ultrasounds talks about the procedure:

CAT scans and MRIs can also be helpful tools because they can help to image smaller cysts than can be seen with an ultrasound.  They are also sometimes used to look for bleeding or other complications. Providers will also often order a complete blood count (CBC) to check for anemia or infection as well as a urinalysis to check for protein or blood in the urine.

DNA Testing for PKD

DNA testing can also be done to check for PKD. In gene linkage testing several family members are tested and compared for markers of PKD.  The test is done on both those who are known to have PKD as well as those without PKD.  Additionally, direct testing can be done without additional family members to look for the markers of the genes known to be linked to PKD. Although genetic testing is accurate, it can be costly for patients and is not always covered by health insurance providers.


This is what a polycystic kidney looks like in an ultrasound:

And for comparison, here is a normal kidney in an ultrasound:

Note the large, dark areas in the top image. These are cysts, labeled "C." Several smaller cysts are can also be seen.  The bottom image is a healthy kidney.








Information from: Just Diagnosed. (n.d.). Retrieved January 28, 2015, from http://www.pkdcure.org/learn/adpkd/just-diagnosed-questions

kidney cyst image: Retrieved January 28, 2015 from https://www.med-ed.virginia.edu/courses/rad/gu/kidneys/Images/adpckdus.jpg

normal kidney image: Retrieved January 28, 2015 from http://www.ultrasoundpaedia.com/uploads/53003/ufiles/kidney/normal/kid-ls-normal.jpg

info : http://www.pkdcure.org/learn/adpkd/just-diagnosed-questions

A Family Affair: Polycystic Kidney Disease

A Family Affair: Polycystic Kidney Disease

Polycystic Kidney Disease (PKD) is genetically linked.  That means it’s passed down through families.  If one parent has PKD there is a 50% chance that each child they have could also have PKD. 

 

PKD has two forms: autosomal dominant (ADPKD) and autosomal recessive (ARPKD). Two genes have been found to correlate with ADPKD. The PKD1 gene is located on chromosome 16 and the PKD2 gene is located on chromosome 4. The gene for ARPKD is located on chromosome 6.

The affected genes are shown below:

When there is a problem with any one of these genes, polycystin, an important protein found in the kidneys is not formed correctly. Subsequently, large cysts form in the kidneys and lead to extreme kidney overgrowth and renal insufficiency. Typically, the kidneys have an adequate filtration rate until patients are in their 30s-40s. In addition to renal problems, patients with PKD often also develop liver cysts, hypertension and in some cases, cerebral aneurysms. 

Many patients have no symptoms at the time of diagnosis. The most common symptom is hypertension, occurring in ~60% of patients. Other common symptoms include:

• Flank (side) pain
• Palpable kidney (a medical professional can feel the kidney by pressing on the side/back)
• hematuria (blood in the urine)  

As cysts increase in size healthy kidney tissue is reduced and the kidneys lose their ability to filter the blood. Without the kidneys to filter blood, toxins would build up in the body.  The current treatment for PKD is dialysis (either peritoneal or hemodialysis) to filter the blood through a machine. The only other option for treatment of PKD is kidney transplant.Unfortunately, dialysis cannot be used indefinitely and patients who don't receive a transplant eventually succumb to complications of End Stage Renal Disease.

As can be seen in the image below, the cysts in PKD take over all the healthy kidney tissue and are found throughout the kidneys. In addition to destroying healthy tissue, the cysts also block the flow of filtrate in the kidneys which can lead to kidney infections.

Family Tree Image retrieved January 21, 2015 from

http://www.renalresource.com/booklets/pkd02.jpg 

Chromosome Image retrieved January 21, 2015 from

 http://www.physio-pedia.com/images/7/70/Chromosomes_pkd.jpg

Kidney image retrieved January 21, 2015 from

http://www.kidneydiseaserelief.com/wp-content/uploads/2014/02/en2476019.jpg

All information from:

Halvorson, C.R., Bremmer M.S., &Jacobs S.C. (Jun 24, 2010). Polycystic kidney disease: inheritance, pathophysiology, prognosis, and treatment. International Journal of Nephrology and Renovascular Disease, volume 3. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108786/