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Nefropatia urica
Acidul uric
- Rezultat din metabolismul purinelor- Solubilitate limitata, dependenta de pH:
- acid: acid uric in urina (pH = 5)- bazic: urat in spatiul extracelular (pH = 7,4)
Nepropatia urica
- NTI urica acuta
- NTI urica cronica
- litiaza urica
Nefropatia urica acuta
Cauze
- sindrom de liza tumorala
- pre-eclampsie/eclampsie
- tratament cu Ciclosporina in transplantul renal
Nefropatia urica acuta
Patogenie
- obstructie tubulara prin cristale de urat si acid uric in conditii de hiperuricemie acuta
- creste presiunea tubulara
- creeste presiunea in reteaua venoasa intrarenala – creste rezistenta vasculara, scade FSR
- scade RFG
Nefropatia urica acuta
Diagnostic
- Hiperuricemie > 15 mg/dl
- Retentie azotata
- LDH seric crescut – masa tumorala mare
- Urina:- cristale de acid uric si monourat sodic- acid uric urinar 150 – 200 mg/dl- acid uric/creatinina > 1
Nefropatia urica acuta
cristale de acid uric
Nefropatia urica acuta
Tratament
-Allopurinol (Milurit) – inhiba xantin oxidaza- cu 2 – 5 zile inainte de cura citostatica- 300 – 600 mg/zi- reducerea dozei in IRC
- Hidratare cu solutie salina 3 – 5 l/zi- Diuretice de ansa – - Alcalinizarea urinii
- Acetazolamida- NaHCO3 – in corectia hiperuricemiei
- Rasburicase (Elitek) – urat oxidaza recombinanta- Dializa
Nefropatia urica cronica
Cause
- Hiperuricemia si guta
- Deficite enzimatice ereditare
Nefropatia urica cronica
Patogenie
- Studii clasice: microtofi in medulara renala
- Hiperuricemia – factor de risc pentru boala renala cronica
- tulburari ale autoreglarii renale
- duce la: HTA, microalbuminurie, IRC
- Asocierea hiperuricemie-IRC:
- expunerea cronica la Pb
- sindrom Lesch-Nyhan (absenta congenitala HGPRT)
Nefropatia urica cronica
Histologie
- Scleroza vasculara
- Reactie inflamatorie si fibroza interstitiala
- Degenerescenta / atrofie tubulara
- Cristale de acid uric/urat in tubii renali
Scleroza vasculara, fibroza interstitiala, atrofie tubulara (HE)
Cristale de acid uric intratubular, degenerescenta tubulara, reactie inflamatorie si fibroza interstitiala. (HE x200)
Nefropatia urica cronica
Clinica
- Guta
- HTA
- Litiaza renala urica
- Pielonefrita cronica litiazica
Nefropatia urica cronica
Paraclinic
- Hiperuricemie
- Hiperuricozurie
- Hematurie
- Proteinurie de tip tubular
- Cristale acid uric si monourat sodic in urina
Nefropatia urica cronica
Tratament
- Reducerea aportului de purine
- Hidratare +/- alcalinizarea urinii
- Inhibitori xantin-oxidaza
Allopurinol 50 – 300 mg/zi
Febuxostat 40 – 80 mg/zi
- Reducerea altor factori de risc: HTA, DZ, obezitate etc