Chronic Kidney Disease|Symptoms and Stages|Treatment

What is Chronic Kidney Disease ?

Chronic kidney disease or often called chronic kidney failure is a common and serious medical problem. Chronic kidney disease is defined as the state resulting from a permanent (and usually progressive) reduction in kidney function. Chronic kidney happens gradually over time, usually months to years and usually permanent loss of kidney function over time.

The kidneys can fail acutely from a variety of causes including acute infections, injuries, poisonings and acute inflammatory disease of the kidney (nephritis). The threshold at which these develop is at around 40 per cent of normal excretory capacity

The term kidney failure normally implies a reduction in the glomerular filtration rate. Insidious (silent) progressive kidney disease can cause a 50% reduction in with glomerular filtration without causing any symptoms.

Knowledge of the patient's age, gender, and body-weight applied to the Cockcroft–Gault formula:

Glomerular Filtration Rate (GFR)=
[ (140 – age in years) × weight (kg) ]/plasma creatinine (µmol/l) × 0.82 (subtract 15 per cent for females)

Chronic kidney disease is divided into 5 stages of increasing severity (see Table below). Stage 5 chronic kidney failure is also referred to as end-stage renal disease, wherein there is total or near-total loss of kidney function and patients need dialysis or transplantation to stay alive.

Stage	Description	GFR* mL/min/1.73 m²
1	Slight kidney damage with normal or increased filtration	More than 90
2	Mild decrease in kidney function	60-89
3	Moderate decrease in kidney function	30-59
4	Severe decrease in kidney function	15-29
5	Kidney failure; requiring dialysis or transplantation	Less than 15

However, this grading of the severity of renal failure has limitations. There is a poor correlation between the actual glomerular filtration rate and symptoms, for example, breathlessness by pulmonary oedema or acidosis, fatigue by anaemia, muscle weakness by abnormalities in calcium and phosphate.

The decision when to start dialysis should be made after integrating knowledge of the estimated glomerular filtration rate, symptoms, and recognition of complications. Decisions should not be based on estimates of plasma creatinine or urea.

The National Kidney Disease Outcome Quality Initiative reported that end-stage renal disease has dramatically increased in the past two decades, and estimated that close to 20 million Americans probably have early stages of CKD.

The fact that as many as 30 per cent of new patients starting renal replacement therapy meet a nephrologist for the first time less than 3 months before dialysis is begun. There are about 500 to 1000 patients per million population with significant chronic kidney impairment. Examples include patients with malignant urinary tract obstruction, diabetes mellitus, renovascular disease with widespread cerebro- and cardiovascular disease.

The incidence is higher in males (1.3:1), in areas of social deprivation, and in particular ethnic groups. In the United Kingdom it is 3.5 times higher in citizens of Asian or Afro-Caribbean backgrounds. In 1997 in Australia the incidence in Aboriginals was six to seven times higher than in Caucasoids. In New Zealand the incidence in Maoris is three to four times higher than in Caucasoids.

Kidney disease is more common among Hispanic, African American, Asian or Pacific Islander, and Native American people. These ethnic variations (which are related to the higher prevalence of diabetes and hypertension) can account only for part of the huge difference in the incidence of end stage kidney failure between Europe and the United States.