Polycystic Kidney Disease

 

Welcome to PT 635 Pathophysiology of Complex Patient Problems This is a wiki created by and for the students in the School of Physical Therapy at Bellarmine University in Louisville KY. Please do not edit unless you are involved in this project, but please come back in the near future to check out new information!!

Original Editors - Emily Hartman from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Lead Editors - Your name will be added here if you are a lead editor on this page.  Read more.

Definition/Description

Polycystic Kidney Disease (PKD) is a genetic kidney disease which causes large benign cysts to form on the kidneys. The cysts are fluid filled cavities (seen in Figure 1) that can ultimately impede kidney function leading to degeneration of renal tissue and renal failure.   Cysts can range anywhere from microscopic in size to several centimeters in diameter.   A cyst begins as a protrusion of the nephron and can occur anywhere along its length.   Most cysts detach from the nephron, and eventually enlarge and fill with either clear fluid or fluid that contains blood or white blood cells.

There are two types of PKD; autosomal dominant and autosomal recessive. Autosomal dominant PKD, or ADPKD, is the most common form of PKD and typically manifests itself in middle aged adults while autosomal recessive PKD is less common and typically manifests itself in childhood. Autosomal recessive PKD is the more serious form and often leads to death in infancy or early childhood.   For a person to inherit ADPKD, it takes a mutated gene from only one parent, while it takes a mutated gene from both parents for a person to inherit ARPKD (see Figures 2 and 3).

Prevalence

ADPKD affects approximately 600,000 Americans; however, the number could actually be higher as many adults who have PKD do not yet exhibit symptoms.   Each child born to a parent with the gene for ADPKD has a 50% chance of inheriting the disease.   Approximately 10% of those in end stage renal failure have ADPKD.

Characteristics/Clinical Presentation

People with ADPKD may not know they have the disease because their symptoms have not yet manifested themselves. ADPKD signs and symptoms typically begin to show themselves between the ages of 30 and 40.

Symptoms/Signs for PKD include:
• high blood pressure
• back or side pain related to enlarged kidneys
• headache
• increase in the size of the abdomen due to enlarged kidneys ( see Figures 4 and 5)
• blood or protein in the urine
• frequent urination
• kidney stones
• kidney failure
• urinary tract or kidney infections

Symptoms that are also associated with PKD include:
• drowsiness
• joint pain
• nail abnormalities
• painful menstruation

Associated Co-morbidities

Cardiovascular complications may include high blood pressure or hypertension, cerebral aneurysms, and mitral valve prolapse (MVP).  MVP is present in approximately 26% of people who have ADPKD compared to 2%-3% of the general population.  Symptoms associated with MVP are heart palpitations, a feeling that the heart is fluttering or racing, and chest pain that is not associated with exercise or exertion.  Also, people with ADPKD have approximately a 5%-10% risk of developing intracranial aneurysms.  The symptoms of a ruptured aneurysm include sudden severe headache, pain in moving the neck, nausea and vomiting, and loss of consciousness.  A person experiencing an intracranial aneurysm will require immediate medical attention as it is a medical emergency.  According to the PKD Foundation website, "Patients with ADPKD and a family history of intracranial aneurysms have a higher incidence of developing an aneurysm (22%) and should be screened more frequently."

Many people with ADPKD develop liver cysts; however, they rarely occur in those under the age of 30.  Liver cysts tend to develop and grow in size as the person ages.  Though this leads to an increase in the size of the liver, the amount of functioning liver tissue remains relatively unvarying.  Both genders are susceptible to liver cysts; however women tend to present with cysts at a younger age while men tend to present with more progressive liver disease.  Pregnancy is a factor that increases the likelihood and size of liver cysts in women with PKD.

Medications

There is no cure for PKD, so the best way to manage it is by controlling or minimizing symptoms. Controlling blood pressure is one of the most important ways to manage PKD. While it is unsure which blood pressure medications are best for the PKD patient population, many nephrologists agree that ACE inhibitors (Angiotensin Converting Enzyme inhibitors) or ARB (Angiotensin Receptor Blockers) are good medications to start with.  Both of these medications work via various pathways to block or inhibit angiotensin II; an enzyme that constricts the blood vessels thereby increasing blood pressure.

As stated above, urinary infections are common in people with PKD. Prompt administration of antibiotics for management of kidney, bladder, or urinary tract infections is important for people with PKD as well as drinking plenty of fluids to dilute blood in the urine.

PKD patients should avoid using all NSAID (Non Steroidal Anti Inflammatory Agents) products such as aspirin, Advil, Aleve, etc. unless told to do so by a physician due to the negative effects on the kidneys.  Patients with PKD may take acetaminophen (Tylenol) for their back and flank pain.  Unlike NSAIDS, acetaminophen does not have the same negative effects on kidney function; however, overtime, usage of acetaminophen can have negative effects on the liver.

Diagnostic Tests/Lab Tests/Lab Values

A urinalysis can be used to determine if there is blood or protein in the urine.   If the disease has progressed the enlarged kidneys may be palpable upon examination.   An ultrasound or CT scan can be used to determine if a malignancy is present, and surgery may be necessary to make a definitive diagnosis.   Genetic testing can also be done by taking and comparing a blood sample from the person and three family members who are either known to have or not have PKD.

Etiology/Causes

A positive family history of PKD is reported in approximately 75% of cases.   ADPKD results from a genetic mutation on the short arm of chromosome 16.   According to the PKD Foundation website, 85% of mutations in ADPKD occur in chromosome 16 (PKD1 gene) while 15% of mutations in ADPKD occur in chromosome 4 (PKD2 gene): see Figure 6.

Systemic Involvement

add text here

Medical Management (current best evidence)

add text here

Physical Therapy Management (current best evidence)

add text here

Alternative/Holistic Management (current best evidence)

add text here

Differential Diagnosis

add text here

Case Reports/ Case Studies

add links to case studies here (case studies should be added on new pages using the case study template)

Resources

add appropriate resources here

Recent Related Research (from Pubmed)

Failed to load RSS feed from http://eutils.ncbi.nlm.nih.gov/entrez/eutils/erss.cgi?rss_guid=1x_POZXjwvkjsbqoxrw-rdu4DMX7g2mfhld--JC3_3sMGGWYzP|charset=UTF-8|short|max=10: Error parsing XML for RSS

References

see adding references tutorial.