Renal (kidney) cystic disease is not a single disease. The term encompasses a number of diseases with differing origins but a common factor – cysts. Specialists at the Glickman Urological and Kidney Institute have experience in successfully treating all manifestations of cystic disease regardless of its origins.
What is a cyst?
Think of a cyst as an internal pimple. It is a closed cavity or sac, lined by epithelium (skin) and filled with fluid or semi-solid material. Cysts can appear nearly anywhere in the body. The cysts to be discussed here are those that appear in the kidney and urinary tract.
- Congenital cystic disease
- Usually diagnosed prenatally with sonograms before symptoms are present.
- Autosomal dominant polycystic kidney disease
- Chronic flank pain and/or intermittent blood in the urine (hematuria). Some may have cyst hemorrhage, kidney infections, or kidney stones. Those in their 50s often develop hypertension and chronic renal failure. Most progress to end stage renal disease in their 60s.
- Autosomal recessive polycystic kidney disease
- ARPKD usually co-exists with liver disease. Infants and younger children may develop hypertension (high blood pressure). Some will show growth retardation. The disease may progress to kidney failure and require transplantation. Children aged 4 to 8 may not have particularly bad kidney disease, but co-existing liver disease may dominate their health circumstances. By age 12 many of these children will experience variceal bleeding, or bleeding from the veins that line the esophagus and stomach. They are also susceptible to bacterial inflammation of the bile duct (cholangitis) and thrombocytopenia. This is a term for low platelet counts. Platelets are blood cells that help the blood to clot.
- Nephronophthisis-medullary cystic disease
- In children, this disorder can lead to a failure to thrive, growth retardation, bone deformities, or muscle spasms caused by low calcium. Juveniles may have poor bone formation and neurologic abnormalities. They may also have visual problems such a progressive loss of their peripheral vision (retinitis pigmentosa) and retinal degeneration. Adults can develop polyuria (excessive urination) polydipsia (excessive thirst, anemia (low red blood cells) and progressive renal failure.
- Acquired renal cysts
- These appear frequently in patients with end-stage renal disease, particularly those on hemodialysis. Treating physicians anticipate these cysts in these patients. They are characterized by flank pain and blood in the urine (hematuria).
- Simple renal cysts
- These seldom create noticeable symptoms and are usually discovered during the course of an examination for other problems. Some do grow large enough to become a mass that can be felt, cause pain in the lower sides or in the abdomen, and/or blood in the urine.
- Medullary sponge kidney
- Patients with MSK may have flank pain, blood in their urine, and elevated calcium levels in urine. This latter symptom is detected by urinalysis.
- Malignant cysts
- These pre-cancerous cysts are present in perhaps 1% of those with renal cell carcinoma. The symptoms are those of kidney cancer – persistent fatigue, unexplained weight loss, recurrent fevers, high blood pressure (hypertension), swelling (edema) in the ankles, a feeling of poor health, and blood in the urine (hematuria).
A number of cyst problems are inherited or appear at birth and others are associated with diseases. Some cysts just appear. Studies conducted during autopsies have found that half of all individuals 50 and older have one or more renal cysts.
Other studies have found a third of those aged 50 and older have evidence of one or more cysts that are visible on computed tomography scans.
Congenital cysts – These are often identified during pre-natal sonograms. After birth, they may be noted as a palpable mass in the infant’s flank. An intravenous pyelogram in which a harmless dye is injected and observed by x-rays as it moves through the kidneys will determine how well kidneys are functioning.
Autosomal dominant polycystic kidney disease – Gene analysis may be conducted in patients whose families have a history of the disease. This analysis in conjunction with sonograms will detect the disease in 88% of patients younger than 30 years-old and virtually all patients over 30 years-old.
Autosomal recessive polycystic kidney disease – Neonates, children in the first few weeks of life, may have hyponatremia (low sodium levels) in their blood. Urinalysis may show decreased osmolality (particles) or white blood cells in the urine (pyuria). Liver enzyme levels may be elevated. Computed tomography (CT) scans may show enlarged kidneys and ultrasound may produces images of the cysts and anatomic changes in the kidney.
Nephronophthisis-medullary cystic disease – A comprehensive urinalysis will reveal a number of characteristics consistent with NMCD. A genetic-linkage analysis may confirm the diagnosis. Sonography or CT scans will show diminished kidneys and the presence of the cysts.
Acquired renal cysts – Sonography will reveal cysts and CT scans may be used to rule out kidney cancer. Sometimes magnetic resonance imaging (MRI) is used in patients who may be unable to undergo the CT procedure.
Simple renal cysts – X-rays and sonography will identify cysts. The challenge is to determine whether they are benign or malignant. An additional CT scan can help differentiate benign cysts from malignant ones.
Medullary sponge kidney – Intravenous pyelograms will reveal specific characteristic features of these cysts.
Malignant cysts – Intravenous pyelograms (IVP) will reveal features that indicate malignancy. Magnetic resonance imaging (MRI) may be used in patients who are allergic to the dye used in the IVP or to supplement the information gathered by IVP.
In all these diseases, histology (the microscopic study of tissue structures) will offer additional information on characteristics of tissue and cells that are relevant to each disease. This information, coupled with the images, and a variety of laboratory tests on blood and urine will create the diagnosis
Congenital cysts – Care is focused on maintaining an adequate daily intake of fluids and sodium to compensate for the excessive excretion of sodium and the production of large volumes of dilute urine. Enlarged kidneys can interfere with breathing and other functions necessitating surgical intervention.
Autosomal dominant polycystic kidney disease – There is no cure as of yet. Primary treatment is focused on controlling disease-associated symptoms such as high blood pressure. Many of these patients, perhaps half, will have significant pain from kidney stones, blood clots and infection. Women with ADPKD are at significant risk of urinary tract infections. Surgical intervention in appropriate cases may provide relief from pain and other symptoms for several years. Minimally invasive (laparoscopic) surgical techniques, many of which have been developed at Cleveland Clinic, have produced excellent results.
Autosomal recessive polycystic kidney disease – There is no cure as yet for ARPKD. In childhood, treatment is focused on supportive measures such as dialysis. Blood pressure medications may be used to control hypertension. Advanced disease may require dialysis. Enlarged kidneys may affect breathing and other functions necessitating kidney removal.
Nephronophthisis-medullary cystic disease – Salt supplementation may improve kidney function and slow the deterioration of the kidneys. End stage kidney disease is treated with dialysis and may be followed by kidney transplantation.
Acquired renal cysts – Salt supplementation can improve or stabilize kidney functions and slow the destruction of the kidneys. Bleeding is a concern. Bed rest and mild analgesics can often control mild bleeding episodes associated with the disease. End-stage disease requires dialysis or kidney transplantation.
Simple renal cysts – Observation is the treatment for most of these cysts. Minor cysts are usually managed with medications to relieve pain. There are a variety of minimally invasive surgical options to improve blood and urine flow, and to remove affected sections of the kidney.
Medullary sponge kidney – There is no cure for MSK. Treatment is focused on reducing the appearance of kidney stones and urinary infections.
Malignant cysts – When these turn cancerous, the treatment is similar to that for kidney cancer. Nephrectomy, surgical removal of the kidney, is the standard of care.