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