Diagnosis of chronic renal failure

Stages of diagnosis of chronic renal failure.

• Medical history: presence and duration of proteinuria, arterial hypertension, delayed physical development, recurrent urinary tract infection, etc.
• Family history: indications of polycystic disease, Alport syndrome, systemic connective tissue diseases, etc.
• Objective examination: growth retardation, underweight, skeletal deformities, signs of anemia and hypogonadism, increased blood pressure, pathology of the fundus, decreased hearing acuity, etc.
• Instrumental examination methods allow to establish the etiology of the underlying disease that led to chronic renal failure. They include ultrasound examination (US) of the urinary system with assessment of renal blood flow, micturition cystourethrography, excretory urography, nephroscintigraphy, nephrobiopsy, densitometry, etc.
• Clinical, laboratory and instrumental studies to determine the severity of chronic renal failure: determination of creatinine concentration, urea nitrogen, SCF.
• Diagnostics of complications of chronic renal failure: determination of the content of total protein, albumin, potassium, sodium, calcium, phosphorus, iron, ferritin and transferrin, parathyroid hormone, hemoglobin, alkaline phosphatase activity, absolute lymphocyte count, daily excretion of protein, electrolytes, ammonia and titratable acids, renal concentrating capacity; assessment of acid-base balance; electrocardiography, echocardiography, blood pressure monitoring, radiological confirmation of osteodystrophy, etc.

Depending on the disease that caused the irreversible death of nephrons, chronic renal failure is diagnosed both in the early stages of development and in the decompensation stage. For example, with severe glomerulonephritis (hematuria, proteinuria, arterial hypertension, edema), chronic renal failure is diagnosed earlier. In the case of latent hereditary and congenital nephropathies, chronic renal failure is determined only in the terminal stage.

The presence of thirst, subfebrile temperature, polyuria, delayed physical development (more than 1/3 of the age norm) in a child should serve as a reason to exclude chronic renal failure. If laboratory tests confirm polyuria, nocturia, hypoisosthenuria, anemia, azotemia and electrolyte disturbances, the diagnosis of chronic renal failure leaves no doubt. The concentration of urea does not always accurately reflect the severity of the impairment of the functional capacity of the kidneys and the mass of functioning nephrons. In a number of diseases, urea is not only filtered, but partially reabsorbed and secreted. The content of creatinine in the blood is considered a more stable indicator. The amount of its secretion and reabsorption is insignificant, so its concentration in the blood is used to determine glomerular filtration.

Differential diagnosis of chronic renal failure

In the early stages of chronic renal failure, polyuria is often mistakenly interpreted as:

• pituitary diabetes insipidus, but the lack of effect from the use of adiurecrin, a negative test with pituitrin and hyperazotemia allow us to suspect chronic renal failure;
• acute renal failure; unlike chronic renal failure, it is characterized by a sudden onset, an inverse sequence in the development of the oliguric and polyuric phases, and a better prognosis.

Severe anemia in chronic renal failure is often mistakenly interpreted as anemia of unknown etiology. Resistance to antianemic therapy, polyuria, hyposthenuria and subsequent development of hyperazotemia indicate chronic renal failure.

In the terminal stage of chronic renal failure, erroneous diagnosis is practically excluded, which is associated with the severity of characteristic clinical symptoms.

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