Diabetic nephropathy

Image:Nodular glomerulosclerosis.jpeg Diabetic nephropathy (nephropatia diabetica), also known as Kimmelstiel-Wilson syndrome and intercapillary glomerulonephritis, is a progressive kidney diseasecaused by angiopathyof capillariesin the kidneyglomeruli. It is characterized by nodular glomerulosclerosis. It is due to longstanding diabetes mellitus, and is a prime cause for dialysisin many Western countries.

History

The syndromed was discovered by BritishphysicianClifford Wilson(1906-1997) and Germany-born Americanphysician Paul Kimmelstiel(1900-1970) and was published for the first time in 1936.

Epidemiology

The syndrome can be seen in patients with chronicdiabetes(15 years or more after onset), so patients are usually of older age (between 50 and 70 years old). The disease is progressive and may cause deathtwo or three years after the initial lesions. and is more frequent in women. Diabetic nephropathy is the most common cause of chronic kidney failure and end-stage kidney disease in the United States. People with both type 1 and type 2 diabetes are at risk. The risk is higher if blood-glucose levels are poorly controlled. However, once nephropathy develops, the greatest rate of progression is seen in patients with poor control of their blood pressure.

Etiopathology

The earliest detectable change in the course of diabetic nephropathy is a thickening in the glomerulus. At this stage, the kidney may start allowing more albumin(plasma protein) than normal in the urine(albuminuria), and this can be detected by sensitive medical testsfor albumin. This stage is called "microabuminuria". It can appear 5 to 10 years before other symptoms develop. As diabetic nephropathy progresses, increasing numbers of glomeruli are destroyed by nodular glomerulosclerosis. Now the amounts of albumin being excreted in the urine increases, and may be detected by ordinary urinalysistechniques. At this stage, a kidney biopsyclearly shows diabetic nephropathy.

Signs and symptoms

Kidney failure provoked by glomerulosclerosis lead to fluid filtration deficits and other disorders of kidney function. There is an increase in blood pressure(hypertension) and of fluid retention in the body (edema). Other complicationsmay be arteriosclerosisof the renal arteryand proteinuria(nephrotic syndrome).

Throughout its early course, diabetic nephropathy has no symptoms. They develop in late stages and may be a result of excretion of high amounts of protein in the urine or due to renal failure:

• edema: swelling, usually around the eyesin the mornings; later, general body swelling may result, such as swelling of the legs
• foamy appearance or excessive frothing of the urine
• unintentional weight gain (from fluid accumulation)
• anorexia(poor appetite)
• nauseaand vomiting
• malaise(general ill feeling)
• fatigue
• headache
• frequent hiccups
• generalized itching

The first laboratory abnormality is a positive microalbuminuria test. Most often, the diagnosis is suspected when a routine urinalysis of a person with diabetes shows too much protein in the urine (proteinuria). The urinalysis may also show glucosein the urine, especially if blood glucose is poorly controlled. Serum creatinineand BUNmay increase as kidney damage progresses.

A kidney biopsyconfirms the diagnosis, although it is not always necessary if the case is straightforward, with a documented progression of proteinuria over time and presence of diabetic retinopathyon examination of the retinaof the eyes.

Treatment

The goals of treatment are to slow the progression of kidney damage and control related complications. The main treatment, once proteinuria is established, is ACE inhibitordrugs, which usually reduces proteinuria levels and slows the progression of diabetic nephropathy. Many studies have shown that related drugs, angiotensin receptor blockers(ARBs), have a similar benefit. In fact, a combination may be best.

Blood-glucose levels should be closely monitored and controlled. This may slow the progression of the disorder, especially in the very early ("microalbuminuria") stages. Medications to manage diabetes include oral hypoglycemic agents and insulininjections. As kidney failure progresses, less insulin is excreted, so smaller doses may be needed to control glucose levels.

The dietmay be modified to help control blood-sugar levels.

High blood pressure should be aggressively treated with antihypertensive medications, in order to reduce the risks of kidney, eye, and blood vessel damage in the body. Therefore, it is the most effective way of slowing damage from diabetic nephropathy. It is also very important to control lipid levels, maintain a healthy weight, and engage in regular physical activity.

Patients with diabetic nephropathy should avoid taking the following drugs:

• Contrast agents containing iodine
• Commonly used non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofenand naproxen, or COX-2inhibitors like Celebrex, because they may injure the weakened kidney.

Urinary tractand other infectionsare common and can be treated with appropriate antibiotics.

Dialysismay be necessary once end-stage renal disease develops. At this stage, a kidney transplantationmust be considered. Another option for type 1 diabetes patients is a combined kidney-pancreas transplant.

Prognosis

Diabetic nephropathy continues to get gradually worse. Complications of chronic kidney failure are more likely to occur earlier, and progress more rapidly, when it is caused by diabetes than other causes. Even after initiation of dialysis or after transplantation, people with diabetes tend to do worse than those without diabetes.

Complications

Possible complications include:

• hypoglycemia(from decreased excretion of insulin)
• rapidly progressing chronic kidney failure
• end-stage kidney disease
• hyperkalemia
• severe hypertension
• complications of hemodialysis
• complications of kidney transplant
• coexistence of other diabetescomplications
• peritonitis(if peritoneal dialysis used)
• increased infections

Reference

• Kimmelstiel P, Wilson C. Benign and malignant hypertension and nephrosclerosis. A clinical and pathological study. Am J Pathol 1936;12:45-48.

External links

• Diabetic nephropathy. HealthCentral.
• Diabetic nephropathy. MedlinePlus Medical Encyclopedia. Text from this public domain article was partially used here.es:Nefropatía diabética

sv:Diabetesnefropati

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It uses material from the http://en.wikipedia.org/wiki/Diabetic+nephropathy Wikipedia article Diabetic nephropathy.