Chronic Kidney

He goes to the emergency room, where the nurse and doctor appear very concerned. After reviewing the blood work, the emergency room doctor informs him that he has “kidney failure”.

The kidneys help to remove unwanted substances from the body. They also help to regulate water balance, the level of certain vital chemicals in the body, and produce a chemical required to make red blood cells. The kidneys act as filters, which retain substances the body needs, while removing substances it does not need. Some of these unwanted substances are harmful to the body and may result in illness or death if they are allowed to accumulate. There are also several ‘pumps’ in the kidney which help in regulating chemicals important to body function. The level of these chemicals in the body must be precisely regulated. Erythropoietin, a hormone produced by the kidney, stimulates the bone marrow to produce red blood cells, which help to carry oxygen and nutrients to vital tissues and organs. A low blood count (anemia) may be one of the consequences of poorly functioning kidneys.

The most common cause of chronic kidney disease in the United States is diabetes. Hypertension is the second commonest cause. Other causes include glomerulonephritis (inflammation of the kidneys), polycystic kidney disease, obstruction to the flow of urine (as caused by an enlarged prostate or kidney stones), medications (including over the counter pain medications), and certain infections (hepatitis B and C, HIV).

Roughly 26 million Americans have chronic kidney disease. Because kidney disease has few symptoms until the very late stages, many people (including Michael) are unaware that they have it. There is a belief that back pain is a common symptom of kidney disease. On the contrary, back pain rarely indicates kidney disease. Kidney stones or kidney infections may cause back pain, but most types of kidney disease will not. The symptoms of kidney disease, when present, are usually not specific for the kidneys, and must be viewed in the right context. Leg swelling, facial swelling, weight gain and shortness of breath may develop as a result of the inability of the kidneys to remove water from the body. Weakness, fatigue and nausea may result if poisonous chemicals accumulate in the body. Weakness may also develop because of anemia.

A blood test and a urine test are the simplest ways to detect kidney disease. The blood test may show an elevated blood creatinine as well as BUN (blood urea nitrogen). Elevations in these chemicals are a reflection of the body’s inability to remove waste products from the body. These results are used to calculate a number called the GFR (glomerular filtration rate) which estimates the severity of the kidney disease. A lower GFR indicates more severe kidney disease. A urine test may show protein in the urine, which may indicate kidney disease before blood tests become abnormal. An ultrasound of the kidneys can show evidence of obstruction, or kidney stones, and also estimates the size of the kidneys. In most cases, patients with chronic kidney disease have small kidneys, except in polycystic kidney disease, where the kidneys are large. A biopsy of the kidney may be recommended if the cause of the kidney disease is not apparent from the clinical evaluation.

Because diabetes and hypertension are the commonest causes of kidney disease in the United States, we can prevent chronic kidney disease by preventing these illnesses. Blood pressure control in persons already diagnosed with hypertension prevents or delays the onset of chronic kidney disease.

In diabetics, the use of a type of medicine called ACE inhibitors (e.g. Lisinopril) can delay the progression of kidney disease. Another type of related medications (called ARBs) is also useful. Patients with chronic kidney disease may be placed on special diets that restrict sodium (to decrease swelling and blood pressure), potassium, and phosphorus. Medications may be prescribed if dietary control is not effective. If the kidney function deteriorates to a GFR less than 10, then dialysis will be required to preserve life. The other option for patients at this end stage of kidney disease is a kidney transplant.

The most common causes of kidney function are preventable or controllable. Careful attention to our day to day activities (diet, exercise) as well as regular assessment of the blood sugar, blood pressure and the kidney function will help to preserve kidney function and quality of life.