How is renal cystic disease diagnosed?
How is renal cystic disease diagnosed?
- 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