Understanding Your Kidneys

Chronic Kidney Disease:

Chronic kidney disease (CKD) means that your kidneys are not working as well as they once did.  Various conditions can cause CKD.  Severity can vary but most cases: are mild or moderate, occur in older people, do not cause symptoms, and do not progress to kidney failure.  People with any stage of CKD have an increased risk of developing heart disease or stroke.  This is why it is important to detect even mild CKD, as treatment may not only slow down the progression of the disease, but also reduce the risk of developing heart disease or stroke.

Understanding the kidneys and urine

In the inner part of the kidneys, tiny blood vessels cluster together to form structures called glomeruli.  Each glomerulus is like a filter.  The structure of the glomerulus allows waste products and some water and salt to pass from the blood into a tiny channel called a tubule.  The liquid that remains at the end of each tubule is called urine.  The urine then passes down a tube called a ureter, which goes from each kidney to the bladder. back links  Urine is stored in the bladder until it is passed out of the body.

The main functions of the kidneys are to:

  • Filter out waste products from the bloodstream, to be passed out in the urine.
  • Help control blood pressure – partly by the amount of water passed out of the body as urine and partly by making hormones which are involved in blood pressure control.
  • Make a hormone called erythropoietin, which stimulates the bone marrow to make red blood cells. This is needed to prevent anemia.
  • Help keep various salts and chemicals in the blood at the right level.

What causes chronic kidney disease?

A number of conditions can cause permanent damage to the kidneys and/or affect the function of the kidneys and lead to CKD.  The three most common causes of renal disease in adults are:

  • Diabetes – Diabetic kidney disease is a common complication of diabetes.
  • High blood pressure – Untreated or poorly treated high blood pressure is a major cause of CKD.  However, CKD can also cause high blood pressure, as the kidney has a role in blood pressure regulation.  About nine out of ten people with CKD stages 3-5 have high blood pressure.
  • Aging kidneys – There appears to be an age-related decline in kidney function.  About half of people aged 75 or more have some degree of CKD.  In most of these cases, the CKD does not progress beyond the moderate stage unless other problems of the kidney develop, such as diabetes.

Other less common conditions that can cause CKD include diseases of the glomeruli, such as glomerulonephritis (inflammation of the glomeruli in the kidneys.)  In many cases a kidney biopsy may be necessary if certain kidney conditions are suspected.

Glomerulonephritis includes a range of immune-mediated disorders that cause inflammation within the glomerulus and other compartments of the kidney. Glomerulonephritis results from a variety of immune and inflammatory mechanisms.  It is often described as primary, when there is no associated disease elsewhere, or secondary, when glomerular involvement is part of a systemic disease such as systemic lupus erythematous (SLE).

Such conditions include:

  • Minimal Change Disease
  • Focal Segmental Glomerulonephritis
  • Membranous Neuropathy
  • Membranoproliferative Glomerulonephritis
  • IgA Nephropathy
  • Diffused Proliferative Glomerulonephritis
  • Crescentic Glomerulonephritis

The treatment of glomerular disease depends on factors such as: acute vs chronic, the underlying cause, and the severity of the condition.  Some forms of glomerular disease, such as that caused by infection, improve after the infection is treated.  Other types of glomerular disease may require treatment with immune suppressant medications.  Some forms of glomerular disease do not require treatment, while others do not respond to any therapy.  It is important to establish a close relation with your nephrologist to monitor the response of treatment and the progression of the disease.

References:

http://www.patient.co.uk/health/chronic-kidney-disease

http://www.patient.co.uk/doctor/Glomerulonephritis-(GN).htm

http://www.uptodate.com/contents/glomerular-disease-overview-beyond-the-basics

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