American Medical Association Family Medical Guide - American Medical Association [537]
No treatment is required for a painless, noncancerous kidney cyst. If it grows large enough to press on other organs or is causing discomfort or pain in the back or abdomen, the cyst may be drained by inserting a hollow needle into it (guided by ultrasound, CT, or MRI) and withdrawing the fluid. If it becomes large enough to be painful, fluid can be removed with a needle (aspirated) periodically, or the cyst can be drained with laparoscopy. If the cells in the fluid are found to be normal, no treatment is needed. If a cyst recurs after being drained, a doctor may perform laparoscopic surgery to remove it permanently. If a cyst is found to be cancerous, surgery is performed to remove part or all of the affected kidney. The healthy kidney will increase in size and level of function and do the work of both kidneys.
Polycystic Kidney Disease
Polycystic kidney disease is an inherited disease characterized by the growth of numerous fluid-filled cysts in the kidneys. The cysts grow out of the tiny filters (called nephrons) inside the kidneys. The cysts enlarge and eventually separate from the nephrons, and the kidneys begin to enlarge as the cysts multiply. The number of cysts can reach into the thousands. Over time, the cysts may make up the bulk of the kidneys, affecting kidney function and eventually causing kidney failure.
There are two types of inherited polycystic kidney disease—autosomal dominant (the most common type) and autosomal recessive. Autosomal dominant polycystic kidney disease, which primarily affects adults, occurs when a person inherits a copy of the defective dominant gene from only one parent, who also has the disease. Typically, the family has a long history of kidney problems. But in about one fourth of all cases, a mutation of a gene in a parent’s egg or sperm produces the disease for the first time in a family. This form of the disease is the most common life-threatening inherited disorder in the United States, affecting roughly half a million people. The disorder affects men and women in equal numbers.
The autosomal recessive form, which is rare and affects only infants and children, occurs when a copy of the defective recessive gene is inherited from both parents. A third form of polycystic kidney disease, which is not inherited, is called acquired cystic kidney disease and occurs mainly in people who have another long-term kidney disease and are on kidney dialysis (see page 818).
Symptoms
In autosomal dominant polycystic kidney disease, cysts may begin to develop early in life without causing any symptoms. The age at which symptoms first appear varies from person to person, but most people begin to notice signs of the disease between ages 30 and 40. Common symptoms include pain in the back and in the sides between the ribs and hips, headaches, blood in the urine, urinary tract infections, kidney stones, and an enlarged abdomen. High blood pressure is common.
The disorder can affect the entire body, causing liver, pancreas, and intestinal problems. It can also weaken blood vessels, producing an aneurysm (a balloonlike swelling) that can rupture in a blood vessel of the abdomen or brain. Blood vessels in the walls of the intestine or abdomen can also be affected, producing a hernia (see page 762). One quarter of people with polycystic kidney disease have an abnormality in a heart valve, called mitral valve prolapse (see page 591), that causes a fluttering feeling or pounding in the chest, along with possible chest pain. Cysts can also form in the ovaries, testicles, pancreas, spleen, central nervous system, and liver. By age 60 the disease advances to kidney failure in more than half of all affected people. The risk of kidney failure increases in people who have high blood pressure or blood or protein in their urine.
Infants and children who have the rare recessive form of polycystic kidney disease have the above symptoms along with high blood pressure and frequent urinary tract infections. They usually develop kidney failure within a few years of birth; in rare, severe cases, a baby dies