>Clinical Connection

The Division of Nephrology and Hypertension in the Department of Pediatrics at Vanderbilt University School of Medicine evaluates and treats children with congenital or acquired kidney disorders. The research interests of clinicians in the Division include cardiovascular disease in children with chronic kidney disease, the impact of the renin-angiotensin system in the outcome of renal disease, podocyte injury and fibrosis in the development and progression of kidney disease, and cancer-related renal disease.

 

Dr. Tracy Hunley, M.D. 

Dr. Tracy Hunley is a pediatric nephrologist who sees patients in the clinic at the Monroe Carell Jr. Children’s Hospital at Vanderbilt. Among the most common conditions that he sees in his patients are polycystic kidney disease, chronic kidney disease, and proteinuria. Most cases of polycystic kidney disease have an autosomal dominant inheritance pattern, meaning the patient only has one mutated copy of the PKD1 or PKD2 gene. Polycystic kidney disease can be autosomal recessive, meaning the affected individual has inherited two genetic mutations in the PKHD1 gene. Mutations in the HNF1β gene can also lead to the development of renal cysts. Chronic kidney disease is characterized into 5 stages, ranging from mild kidney damage in stage 1 to complete kidney failure in stage 5. Patients with stage 4 or stage 5 kidney disease need to prepare for dialysis or a kidney transplant. These patients may be placed on the UNOS waiting list in the hopes of finding a match for a kidney transplant. Proteinuria refers to an excess of protein in the urine. This can be detected by a dipstick test, where a thin, plastic stick with strips of chemicals on it is placed in a patient’s urine to detect abnormalities. Proteinuria can have a number of causes, including high blood pressure, diabetes, medications, trauma, toxins, infections, or immune system disorders.

Besides seeing patients with these more common kidney conditions, Dr. Hunley also treats patients with rare kidney problems. Two of these that I was able to observe were Hemolytic Uremic Syndrome (HUS) and nutcracker syndrome. HUS is caused by E. coli infections when bacterial toxins enter the bloodstream and damage the blood vessels. The glomeruli in the kidneys become clogged with platelets and damaged red blood cells. This leads to problems with the kidney’s ability to function and can cause kidney failure. Nutcracker syndrome results from the compression of the left renal vein between the abdominal aorta and the superior mesenteric artery. The compression causes renal vein hypertension, which can lead to abdominal pain. Nutcracker syndrome can be treated with endovascular stenting, renal vein re-implantation, or a renal autotransplantation, where the kidney is transferred from its original location to another location in the body to prevent the venous compression.

Figure 1. Nutcracker Syndrome