Back pain is the most common pain symptom reported by people with polycystic kidney disease (PKD). Finding ways to manage the pain associated with this disease is a major component of treatment.
PKD is characterized by the development of cysts, or fluid-filled sacs, in the kidneys. There are different forms of the disease, both acquired and genetic. Two kinds of genetic PKD exist, one which usually manifests in childhood (autosomal recessive) and one whose symptoms generally delay until adulthood (autosomal dominant). Autosomal dominant PKD accounts for the vast majority of cases.
Cysts grow gradually in the kidneys. Once adulthood is reached, kidney space filled by the cysts may cause urinary problems, such as blood in the urine and urinary tract infections. High blood pressure is also common among those with PKD. Though less appreciated, one of the main symptoms of the disease is back pain, which may be acute or chronic.
Back Pain and PKD
There are a number of causes of back pain, and by itself, it is not a good indicator of PKD. If you have a family history of the disease and urinary problems, however, it may be the symptom that leads to diagnosis.
People with PKD may experience back pain due to muscular changes and degenerative changes affecting spinal joints and discs. Kidney cysts can grow very large, adding weight to the abdominal region. According the National Kidney and Urologic Diseases Information Clearinghouse, a cyst-filled kidney can weigh as much as 30 pounds. Extra stomach weight pulls forward on the spine and back muscles, causing the spinal arch in the lower back to increase. This shortens the length of muscles in the lower back and creates chronic tension.
Structures of the spine may suffer from the growing cysts nearby. Often kidneys are more impacted on one side than the other, meaning weight distribution will be uneven. Slowly, posture will adjust to changes in weight distribution with and the pelvis will become uneven. As the pelvis tilts, the spine undergoes a change in alignment (the spine and pelvis are attached via the sacroiliac joints and a network of muscles). Uneven forces may cause degeneration of the sacroiliac joints, facet joints in the spine and spinal discs. Aside from localized pain, spinal misalignment and herniated discs can lead to radicular pain in the form of sciatica if the nerve is impinged by these structures.
Treatments
At present there is no cure for PKD. The disease is associated with a number of serious health complications that usually take effect after the age of 50, including polycystic liver disease and renal failure. Current treatments focus on the management of pain and correlative complications as well as slowing the growth of cysts within the kidneys.
Back pain from kidney cysts can sometimes be managed by physical therapy and postural training, such as the Alexander Technique. This helps people better cope with the uneven weight distribution characteristic of PKD. In some cases, steroid injections are used to simply numb the pain in the lower back and hips. Other medications like over-the-counter anti-inflammatories and prescription pain killers are sometimes prescribed if pain is severe. Surgery for back pain is rare, and is usually only prescribed to those who have degenerative spinal conditions and who conservative treatments have not helped.
Though a unified approach has yet to be identified, there are studies that provide evidence of ways to slow cyst development. One study found that a soy protein-based diet led to less cyst development than a diet heavy in casein protein (found in milk) in animal controls ( http://jasn.asnjournals.org/content/10/2/300.abstract ). Another study showed that increasing water intake actually slowed the proliferation of PKD cells, leading to smaller kidney size in rats ( http://jasn.asnjournals.org/content/17/8/2220.abstract ). A number of drugs are being tested for their ability to slow cyst growth, but none are standard as of yet.
Managing high blood pressure is an important part of PKD treatment. Medication may be part of this management, as well as healthy weight maintenance and a low-sodium diet.
Though there is no cure for PKD at this time, there are steps you can take to slow the disease’s progression and manage its painful symptoms. Acting early can help to delay or prevent kidney failure later on.