biopsia/patologia

Question 1

Kidney has three main histological compartments including glomerular, vascular and tubulointerstitial.

First localize in which department the main injury occurs and to recognize the severity and extent of the renal injury in each department.

Answer 1

Then, the type of injury is to be assessed such as active versus chronic.

Active lesions includes cellular proliferation, crescents, edema, necrosis and acute inflammation while

chronic lesions represent fibrosing conditions such as fibrous crescents, interstitial fibrosis, glomerulosclerosis, tubular atrophy or vascular sclerosis.

Question 2

Glomerular lesions

No or minimal hypercellularity

Answer 2

The first step is to determine whether there is hypercellularity or not.

No or minimal hypercellularity offers usually a limited differential diagnosis.

Then, in such cases further investigations with immunofluorescence (IF) and electron microscopy(EM) are needed along with a detailed clinical history.

If glomerular capillaries are abnormal three main categories are defined; glomerular capillary wall thickening, sclerosis/capillary wall collapse e luminal occlusion

. If the patient has nephrotic syndrome three main diagnosis are considered ; minimal change disease, membranous GN(early stage ) and also amyloidosis in which amyloid deposits can be very subtle to detect on light microscopy.

However, these disorders can be easily differentiated by immunofluorescence and ultrastructural microscopic findings.

Minimal change diseases(MCD) is the most common cause of idiopathic nephrotic syndrome and characterized by absence of pathologic changes by light microscopy but diffuse effacement of foot processes of podocytes by EM.

It is usually a primary disease but it may be secondary to malignant diseases and nonsteroidal anti-inflammatory drugs Proteinuria is generally massive, selective and mostly of abrupt onset

Question 3

biopsia sem ou minima hipercelularidade

1) sem ou minimo achado na microscopia otica
2) anormalidade capilar glomerular

Answer 3

1) sem ou minimo achado na microscopia otica
a) SINDROME NEFROTICA
- DLM
- amiloidose
- GN membranosa em estagio inical
b) HEMATURIA

sind de alport

doença da membrana fina

nefropatia por igA

nefrite lupica classe I ou II

normal

Question 4

doença lesao minima

Answer 4

microscopia eletronica com apagamento dos podocitos

Question 5

NECROSE SEGMENTAR IGA – Glomérulo com área de necrose segmentar e cariorrexe às 9h. A microscopia de imunofluorescência foi condizente com Nefropatia da IgA.

Answer 5

definicao de necrose por: 1- ruptura da membrana basal do capilar glomerular com 2- exsudação de fibrina e 3- cariorrexe. Ao menos duas dessas três alterações devem estar presentes para que seja atendido o critério diagnóstico de necrose. Idealmente, a necrose não deve ser avaliada ao PAS com digestão, mas sim, preferencialmente, em cortes histológicos corados pelo HE ou por impregnação pela prata.

Question 6

indicacoes d ebiopsia

Answer 6

• Acute kidney injury of unknown etiology
• Nephrotic syndrome • Proteinuria > 1 g/day
• Isolated hematuria (lower diagnostic yield than proteinuria, exclude urologic causes)
• Reduced kidney function in the setting of a monoclonal paraprotein [(to assess for monoclonal gammopathies of renal significance (MGRS)]
• Rapid rise in serum creatinine or rapid rise of proteinuria in a patient with diabetes with/ without retinopathy
• AKI in an allograft
• Transplant surveillance in a high risk patient (high PRA, positive DSA)