Diagnosis of interstitial nephritis
Last reviewed: 23.04.2024
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In patients with acute tubulointerstitial nephritis, the urinary syndrome is characterized by hematuria (macro- and micro-), abacterial leukocyturia, moderate proteinuria (0.03-0.09% o), and cylindruria. In the morphology of the urinary sediment, lymphocytes and eosinophils are detected.
The tubular dysfunction syndrome manifests itself in a decrease in titrated acidity, a decrease in ammonia excretion and a concentration ability. Possible disruption of the processes of reabsorption and transport in tubules (aminoaciduria, glucosuria, acidosis, hyposthenia, hypokalemia, hyponatremia, hypomagnesemia).
The study of enzymes - markers of mitochondrial activity - reveals mitochondrial dysfunction. The study of urine enzymes in the active phase of acute tubulointerstitial nephritis shows, first of all, an increase in γ-glutamyltransferase, alkaline phosphatase, as well as beta-galactosidase, N-acetyl-O-glucosaminidase and cholinesterase, which emphasizes the interest in the pathological process of the glomerular apparatus.
According to ultrasound and DG, half of patients with acute tubulointerstitial nephritis have an increase in echogenicity of the renal parenchyma, and 20% have an increase in their size. In the CDC regime, there are no signs of a violation of the intra-arterial blood flow. Pulse dopplerometry in 30% of patients shows a decrease in indices of resistance at the level of interlobar and arterial arteries.
Functional disorders in chronic tubulointerstitial nephritis are characterized by a fairly rapid decrease in the secretory and excretory capacity of tubules, manifested by a decrease in the relative density of urine, ammonia and titrated acidity, aminoaciduria, increased excretion of sodium and potassium, and other tubular dysfunctions. Glomerular filtration for a long time remains safe.
Ultrasonography of kidneys in patients with chronic tubulointerstitial nephritis in 50% of cases reveals a violation of the differentiation of the parenchyma on the cortical and brain substance, an increase in the echogenicity of the cortical layer of the kidneys in 38% of children. The results of pulsed dopplerometry show a significant violation of the intrarenal hemodynamics at the level of the arterial artery in patients with chronic tubulointerstitial nephritis.
The diagnosis of tubulointerstitial nephritis is very complicated and requires taking into account all anamnestic, genealogical and clinico-laboratory data, however, in most cases only a morphological examination of the renal biopsy allows a final diagnosis.
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