Creatinine (English: Creatinine), also known as creatinine, creatine and
creatine phosphate metabolism end products, which is mainly generated by
non-enzymatic reactions in muscle creatine phosphate. Normal adults, the daily
amount of creatinine produced is constant, and the amount of creatinine produced
is proportional to the amount of muscle, and therefore the value in general
little men than women. Regular exercise muscle and non-vegetarians value is
higher. Generating a certain amount of creatinine, but not after the filtering
tubular reabsorption. It reflects the excretion of creatinine levels in blood
and glomerular filtration rate, which is the function of the kidneys. When
severe kidney disease, the creatinine excretion is blocked, blood creatinine
levels increased. Determination of creatinine in the blood can be known whether
there is severe renal function impairment, creatinine higher the value, the
greater the kidney disorder; blood creatinine, but only when there is a serious
obstacle to the kidney will be significantly improved, not as early renal
disease indicators. Generally normal to: Men 0.7 ~ 1.2 mg / dL (60 ~ 110 μmol /
L), F 0.5 ~ 1.0 mg / dL (45 ~ 90 μmol / L), the under-five 0.3 ~ 0.5mg/dl.
Blood urea nitrogen urea nitrogen is the main end-product of human protein
metabolism. Deamination of amino acids to generate NH3, and C02, both the
synthesis of urea in the liver, per gram of protein metabolism urea 0.3g. Urea
nitrogen content of 28/60, almost half. Renal excretion of urea is usually the
main organ of urea from the glomerular filtration may be reabsorbed in the
tubules of each segment, but within the renal tubular reabsorption of urine flow
rate, the faster the less, that reached a maximum clearance. And serum
creatinine, as in early renal dysfunction, blood urea nitrogen in the normal
range. When the glomerular filtration rate drops to below 50% of normal, blood
urea nitrogen concentration was increased rapidly. Under normal conditions,
blood urea nitrogen and creatinine ratio (BUN / Scr) value of about 10,
high-protein diet, high catabolic state, water shortages, renal ischemia,
hypovolemia, and some acute glomerulonephritis, are The ratio can increase, even
up to 20 to 30; while low-protein diet, liver disease often makes ratio
decreased, this time called low azotemia.
BUN to fasting normal adults 3.2-7.1mmol / L (9-20mg/d1). Variety of renal
parenchymal lesions, such as glomerulonephritis, interstitial nephritis, acute
and chronic renal failure, renal space-occupying lesions and destructive can
make blood urea nitrogen increased. Multi-renal factors may also cause elevated
blood urea nitrogen, one can rule out uremia diagnostic indicators such as the
kidney and external factors, BUN), 21.4mmol / L (60mg/d1) is.
More vulnerable to the effects of diet, renal blood flow, if protein
degradation factors - infections, intestinal bleeding, elevated blood urea
nitrogen, which will enable hyperthyroidism. Glomerular filtration rate
decreased to the normal 1/2 ~ 1/3, urea nitrogen gradually increased, the ratio
of blood urea nitrogen and serum creatinine under normal circumstances is 10.1,
the ratio increased due to a gastrointestinal hemorrhage , hemolysis, cardiac
dysfunction and tissue breakdown enhancement (burns, fever, adrenocorticotropic
hormone therapy, etc.), mostly pre-renal factors, ratio decreased seen too
little protein intake, severe liver and kidney dysfunction.
Inflammation of renal fibrosis generally less pathological damage, only mild
blood circulation disorders, and injuries limited range, no glomerular and renal
interstitial fibrosis, and no change in renal function. But if in the
inflammatory response of the disease has not been effectively controlled, then
will enter the growth of renal fibrosis, forming period, with a vivid metaphor
for the human skin after the process is the formation of scar impaired renal
fibrosis, The difference is that the non-proliferation of skin scarring damage,
but also damage the kidneys are different ranges have local * early start to
spread.
Impaired renal function induced renal cells under inflammatory stimuli role
of virulence factors, cytokines, growth factors, occur gradually transformed
phenotype, but also to stimulate the kidney fibroblasts into myofibroblasts,
synthesis of a series of cellular secretion extracellular matrix, extracellular
matrix synthesis increased, their degradation and synthesis homeostasis
mechanisms are disrupted, the ultimate cause of a lot of extracellular matrix
deposition, and gradually replace healthy kidney units, resulting in glomerular
sclerosis continues, tubular - interstitial fibrosis, renal vascular fibrosis.
After this time the majority of organizations have kidney fibrosis, the original
kidney function were also damaged, the symptoms began to appear complications,
serum creatinine, blood urea nitrogen rises; renal filtration rate decreased and
so on.
Serum creatinine and blood urea nitrogen levels generally reflect the status
of renal function in patients with renal failure, the higher their level, the
more serious injury of renal function, serum creatinine more serious damage, the
higher the level of urea nitrogen, therefore, active treatment Early kidney
disease, lower serum creatinine and blood urea nitrogen, cut the vicious cycle
of deterioration of the chain, delaying the development of renal fibrosis.
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