Kidney cysts are estimated to occur in 10 percent of healthy adults. These cysts range in size and are typically filled with clear or straw-colored fluid. They can occur spontaneously or be caused by a disease, such as polycystic kidney disease. Rupture of a kidney cyst is unusual but does occur. The most common symptom of a ruptured kidney cyst is pain. It is important to recognize the signs and symptoms of a ruptured kidney cyst and understand the situations that can lead to cyst rupture.
Back and Abdominal Pain
The typical sign of a ruptured kidney cyst is pain. This most often occurs along the flank -- one side of the back -- but may also be located in the abdomen. The pain may be severe and occur suddenly. Alternatively, it can feel like a dull ache. The pain will be constant in the beginning, and changing position does not alter the pain. The pain is related to stretching of the kidney. Occasionally, if blood or cyst fluid leaks into the abdomen, this can irritate the tissues around the intestines. In this case, the person will have a very tender abdomen that is made worse immediately after it is touched -- a symptom referred to as rebound pain.
Other Signs and Symptoms
There are other signs to be aware of in addition to pain. Blood in the urine, seen as light pink to dark red in color, may be present. If there is significant blood loss, low blood pressure may occur, leading to lightheadedness or even passing out. Individuals on peritoneal dialysis -- a type of dialysis involving fluid placed inside the abdomen -- may have blood in the fluid coming out of the abdomen during dialysis if a cyst has ruptured. A fever may develop, either due to an infection in the cyst or the body’s reaction to bleeding. If the cyst is large enough, there may even be a hard mass that can easily be felt.
Causes of Kidney Cysts
Kidney cysts can occur in a variety of conditions, including:
-- Small simple cysts: While cysts can be present at birth, simple cysts become more common after age 50. An estimated that 30 percent of those 70 years and older have a simple kidney cyst, according to a September 2009 "Journal of the American Society of Nephrology" article.
-- Polycystic kidney disease: This is the most commonly inherited cystic kidney disease and includes autosomal dominant and autosomal recessive types. The autosomal dominant type is most common and is not diagnosed until adulthood. The autosomal recessive type becomes apparent in early childhood.
-- Acquired kidney cysts: These cysts occur after starting dialysis for kidney failure, and the number of cysts relates to the time on dialysis.
Causes of Cyst Rupture
Cyst rupture is relatively uncommon. When it does occur, it usually happens under the following circumstances:
-- Growth of the cyst: The exact cause of cyst growth is unknown, but occasionally a kidney cyst grows so quickly that it ruptures.
-- Trauma: Damage to a cyst from trauma, such as a fall from a high height or a serious car accident, can lead either directly to cyst rupture or rupture after significant bleeding into the cyst.
-- Bleeding into a cyst: Bleeding can be spontaneous or related to trauma and can lead to rapid growth of the cyst, resulting in rupture. This is more likely if an individual is taking medications to thin the blood.
-- Infection in a cyst: Infections that start in the bladder can move up to the kidneys and settle in a cyst. Occasionally the infection causes enlargement of the cyst and, in turn, a rupture.
Warnings and Precautions
A ruptured kidney cyst can be a serious health condition resulting in pain and, potentially, changes in kidney function and blood loss. If you notice severe side, low-back or abdominal pain, with or without blood in your urine, contact your doctor. Also contact your doctor if you have a large kidney cyst, polycystic kidney disease or multiple family members with polycystic kidney disease and experience any blood in your urine with pain that might indicate a cyst rupture. If you have a fever in addition to these symptoms, seek medical care right away because you could have a serious kidney infection.