The most characteristic kidney damage in diabetes is diabetic nephropathy, or glomerulosclerosis. Diabetic nephropathy develops in 50% of patients. It largely determines the prognosis of life in young patients with insulin-dependent diabetes.
Among patients with diabetes up to 30 years, 50% die from renal failure.
- At the symptomatic stage, diabetic nephropathy is accompanied by any disorders. Impaired renal function is characterized by an increase in glomerular filtration rate, a change in the circadian rhythm and response to water load.
- For stage I (pre-nephrotic), transient proteinuria is typical. Most often, it is detected by determination in daily urine. Other clinical symptoms, including hypertension, may be absent.
- The II (nephropathic) stage is characterized by the development of nephrotic syndrome. Daily proteinuria increases significantly, becomes resistant. Red blood cells, cylinders (hyaline and granular) are found in the urine sediment. Renal filtration function is reduced, but nitrogen excretion is usually preserved, or transient disorders are observed. In the clinical picture, edema is noted, initially alternating, and later persistent and massive. Secondary nephrogenic arterial hypertension occurs and stably remains. At this stage, hyperlipidemia is more pronounced, and hypoproteinemia are exacerbated.
- On average, after 5 years, the nephrotic stage passes into the III (nephrosclerosis, or azotemia). The clinical picture of this stage is characterized by various symptoms of chronic renal failure. Persistent (malignant) arterial hypertension is noted, which is difficult to correlate with antihypertensive drugs, constant pronounced edema of the whole body, significant proteinuria. Progressive azotemia is accompanied by general weakness, dyspeptic disorders, and sometimes convulsive skeletal muscle contractions.
3-4 years after the appearance of azotemia, uremia develops. A feature of the terminal stage of chronic renal failure in diabetes is that patients die at much lower rates of azotemia (as a rule, blood urea levels are less than 22 mmol / L and creatinine less than 884 mmol / L) than in non-diabetic patients.
The nephrosclerosis stage is characterized by severe hypoproteinemia, hyperlipoproteinemia, anemia, leukocytosis, (in the terminal phase, oliguria and anuria). With the progression of chronic renal failure, a phenomenon can develop: a visible improvement in the course of diabetes, which consists in a decrease in hyperglycemia and glucosuria, mainly due to a decrease in insulin activity and some other reasons.