Nephrology

Nephrology is the subspecialty of internal medicine that focuses on the diagnosis and treatment of diseases of the kidney. Because the kidney performs so many critical functions, nephrologists maintain expertise in primary kidney disorders, but also the management of the systemic consequences of kidney dysfunction. Although the prevention and identification and management of early kidney disease is a large part of general internal medicine practice, nephrologists are usually called upon to assist and manage more complex or advanced nephrologic disorders.

Examples of conditions cared for by nephrologists include primary kidney disorders such as glomerular diseases (such as glomerulonephritis or the nephrotic syndrome), tubulointerstitial kidney diseases, tubular defects, and the effects of toxins on the kidney, including various diagnostic and therapeutic agents. Knowledge of disorders of the kidney vasculature (such as renal artery stenosis), infections and neoplasms of the kidney, and abnormalities of the kidney, collecting system and bladder (such as nephrolithiasis) are important aspects of nephrology practice.

A thorough understanding of the involvement of the kidneys in other systemic diseases (such as vasculitis or heart failure) is a primary role of nephrologists, and because of the central role of the kidney in maintaining blood pressure, nephrologists also possess expertise in the management of hypertension, particularly when difficult to control. Nephrologists also help in managing fluid, electrolyte, and acid-base disturbances, particularly those occurring in advanced kidney disease. A major role of nephrology is the oversight of dialysis (including hemodialysis and peritoneal dialysis) in patients requiring renal replacement therapy, and participation in the kidney transplant process, if indicated.

Many nephrologists work in individual or group practices seeing patients in consultation for other physicians and following patients with chronic kidney disease longitudinally. Nephrologists may also provide in-hospital consultation as part of their practice. Nephrologists also oversee dialysis units which may be associated with their own practice, may be free-standing, or affiliated with a hospital. Some clinicians maintain practices containing a mix of nephrology and general medical patients. In academic settings, nephrologists provide consultative and ongoing care in ambulatory and inpatient settings, perform basic science and clinical research in kidney diseases, and teach medical students and residents.

Conditions a nephrologist treats

Nephrologists can work with you to help diagnose and treat the following conditions:

• blood or protein in urine
• chronic kidney disease
• kidney stones, although a urologist may also treat this
• kidney infections
• kidney swelling due to glomerulonephritis or interstitial nephritis
• kidney cancer
• polycystic kidney disease
• hemolytic uremic syndrome
• renal artery stenosis
• nephrotic syndrome
• end-stage kidney disease
• kidney failure, both acute and chronic

A nephrologist can also be involved when other factors cause kidney disease or dysfunction, including:

• high blood pressure
• diabetes
• heart disease
• autoimmune conditions, such as lupus
• medications

If you’re visiting a nephrologist, they may be involved in performing a variety of tests and procedures or interpreting the results.

Laboratory tests

A wide range of tests can be used to assess the function of your kidneys. These tests are typically performed on either a blood or urine sample.

Blood tests

• Glomerular filtration rate (GFR). This test measures how well your kidneys are filtering your blood. GFR begins to decrease below normal levels in kidney disease.
• Serum creatinine. Creatinine is a waste product and is present at higher levels in the blood of people with kidney dysfunction.
• Blood urea nitrogen (BUN). As with creatinine, finding high levels of this waste product in the blood is a sign of kidney dysfunction.

Urine test

• Urinalysis. This urine sample can be tested with a dipstick for pH as well as the presence of abnormal amounts of blood, glucose, protein, or bacteria.
• Albumin/creatinine ratio (ACR). This urine test measures the amount of the protein albumin in your urine. Albumin in the urine is a sign of kidney dysfunction.
• 24-hour urine collection. This method uses a special container to collect all of the urine that you produce during a 24-hour period. Further testing can be performed on this sample.
• Creatinine clearance. This is a measure of creatinine from both a blood sample and a 24-hour urine sample that’s used to calculate the amount of creatinine that’s exited the blood and moved to the urine.

Procedures

In addition to reviewing and interpreting the results of your laboratory tests, a nephrologist may also perform or work with other specialists on the following procedures:

• imaging tests of the kidneys, such as ultrasounds, CT scans, or X-rays
• dialysis, including placement of the dialysis catheter
• kidney biopsies
• kidney transplants