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Chronic renal failure: diagnosis
Last reviewed: 19.10.2021
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Inspection and Physical Examination
In the terminal stage of chronic renal failure, patients are sluggish, apathetic. Skin pale, dry, icteric, with a gray tinge (anemia and staining with urochromes), with hemorrhages, bruises and traces of scrapings. With pericarditis listen to the noise of friction of the pericardium.
Laboratory Diagnosis of Chronic Renal Failure
Early diagnosis of chronic renal failure is based on laboratory methods.
In favor of chronic renal failure are polyuria with nicturia, persistent arterial hypertension in combination with anemia, symptoms of gastroenteritis and secondary gout, hyperphosphataemia with hypocalcemia.
The most informative and reliable determination of the maximum relative density or osmolarity of urine, the magnitude of CF and the level of creatinine of the blood. Depression of the maximum relative density of urine below 1018 in Zimnitsky's trial with a decrease in CF below 60-70 ml / min indicates an initial stage of chronic renal failure. The method of calculating CF by the formula Cockroft-Gault is more accurate, since it takes into account the age, body weight and sex of the patient.
KF (for men) = (140 - age, years) х m: (72 х Сr), КФ (for women) = (140 - age, years) х m х 0.85: (72 х Сr),
Where m is the body weight, kg; Cr - creatinine of blood, mg / dl.
Azotemia (creatinine more than 1.5 mg / dL) is found in a later stage of chronic renal failure - with a decrease in CF to 30-40 ml / min. Chronic renal failure in diabetic nephropathy is more difficult to diagnose than non-diabetic nephropathies. Diagnosis of chronic renal failure with the help of Zimnitsky's test is difficult because of glucosuria. In addition, with a severe diabetes deficiency in muscle mass and steatosis, the level of creatinine and urea does not reflect the severity of chronic kidney failure. An informative calculation of the CF value by the Cockroft-Gault formula .
With uremic hyperparathyroidism, hyperphosphatemia and hypocalcemia are detected, an increase in the level of the bone fraction of the APF and PTH of the blood. Long-term violations of nutritional status due to chronic renal failure are indicated by hypoproteinemia, hypoalbuminemia.
Instrumental diagnosis of chronic renal failure
Characteristic decrease in the size of the kidneys according to ultrasound or an overview of the X-ray of the kidneys.