Histopath: Renal

Question 1

How can renal pathology be classified?

Answer 1

Anatomically based on what’s affected:

Glomerulous:

• Nephrotic (primary v secondary)
• Nephritic

Tubules + Interstitium (ATN + Tubulointerstital nephritis)

Blood vessels (HUS + TTP)

Question 2

What is nephrotic syndrome?

Answer 2

TRIAD of:

1. Hypoalbuminaemia
2. Proteinuria (>3g/24hr -> PCR ix >300mg/mmol) = frothy urine
3. Oedema - periorbital, gentital ascites and peripheral

Due to breakdown in selectivity of filtration barrier

Question 3

What are the different causes of nephrotic syndrome?

Answer 3

Primary:

• Minimal change disease
• Membranous glomerular disease
• Focal segmental glomerulosclerosis
• Membranoproliferative

Secondary:
- SLE, Diabetes and Amyloidosis

Question 4

What is minimal change disease?

Light microscopy, electron microscopy?

mx?

Answer 4

Most common cause of nephrotic syndrome in children

Light microscopy = NO changes
Electron microscopy = loss of podocyte FOOT PROCESSES

Oral prednisolone 1mg/kg for 4-16w (90% respond well)

Question 5

What is membranous glomerular disease

Light microscopy, electron microscopy?

mx?

Answer 5

Most common cause of nephrotic syndrome in adults

Light microscopy = Diffuse glomerular basement membrane thickening
Electron microscopy = loss of podocyte foot processes + SPIKEY SUBEPITHELIAL deposits

Poor response to steroids –> ACEi / ARB + BP control in all

Question 6

What antibody is found in membranous glomerular disease?

Answer 6

Ab against phospholipase A2 receptor (PLA2R) present in 75%

Question 7

What is focal segmental glomerulosclerosis?

Light microscopy, electron microscopy?

mx?

Answer 7

Most common cause of nephrotic syndrome in Afro-Carribeans

Light microscopy = focal and segmental scarring, hyalinosis
Electron microscopy = loss of podocyte FOOT PROCESSES

ACEi / ARB + BP control in all, 50% will respond to steroids

Question 8

What is membranoproliferative glomerulonephritis?

Light microscopy, electron microscopy?

mx?

Answer 8

More common cause of nephrotic syndrome in low / middle-income countries

Mx:
ACEi / ARB + BP control in all + Treat underlying cause

Least likely

Question 9

What are the main features of nepritic syndrome?

Answer 9

PHAROH:

Proteinuria
Haematuria (cola coloured urine)
Azootemia (High urea + creatinine - basically AKI)
Red cell casts
Oliguria
HTN

Question 10

What are the main causes of nephritic syndrome?

Answer 10

1. Acute post-infectious GN - IMPORTANT
2. IgA nephropathy (Berger disease) - IMPORTANT
3. Rapidly progressive (cresentic) GN
4. Alports syndorme (hereditary nephritis)
5. Thin basement membrane disease (benign familial haematuria)

Question 11

What are the main features of Acute post-infectious GN? ix? mx?

Answer 11

1-3w after streptococcal throat infection / impetigo

Bloods = High ASOT, Low C3

Biospy:

• Light microscopy - increased cellularity of glomeruli / mesangium
• Electron microscopy - subendothelial humps
• Immunoflurescence - granular deposition of IgG and C3 in BM

Supportive mx

Question 12

What are the main features of IgA nephropathy? (bergers)

Answer 12

Most common cause of GN worldwide -> more common in E. Asia / S. Asain descent

Occurs days after UTRI / GI infection, frank haematuria

Deposition of IgA immune complexes -> can progress to ESRF (end stage renal failure)

Question 13

What is the rule of 1/3s re IgA nephropathy?

Answer 13

1/3 = assymptomatic w/ urine dip abnormalities

1/3 = develop CKD

1/3 = develop progressive CKD -> dialysis / transplantation

Question 14

Ix in IgA nephropathy?

Answer 14

Bloods = High IgA

Immunoflourescence = granular deposition of IgA and C3 in mesangium

Question 15

What is rapidly progressive (cresentic) GN?

Answer 15

Most aggressive form of GN - can cause ESRF in weeks

w/ all types = crescents in glomeruli (prolif of macrophages + parietal cells in bowmans capsule)

Question 16

What are the different types of rapidly progressive (cresentic) GN?

Answer 16

o Type 1: Anti-GBM antibody (aka Goodpasture’s disease)
o Type 2: Immune complex mediated
o Type 3: Pauci-immune / ANCA-associated

Question 17

What is Alports syndrome (hereditary nephritis)?

Answer 17

Mutation in type IV collagen alpha 5 chain, X linked

TRIAD of Nephritic syndrome + sensorineural deafness + eye disorders (lens dislocation, cataracts)

Presents at 5-20yrs with nephritic syndrome progressing to ESRF

Question 18

What is thin basement membrane disease (benign familial haematuria)?

Answer 18

AD -> Diffuse thinning of GBM caused by mutation in type IV collagen alpha 4 chain

• Quite common – prevalence is ~5%
• Usually asymptomatic – incidentally diagnosed with microscopic haematuria
• Renal function usually normal
• Excellent prognosis

Question 19

What are the different types of renal cell carcinomas? + histology?

Answer 19

● Clear cell carcinoma – well differentiated (MOST COMMON)

● Papillary carcinoma – commonest in dialysis-associated cystic disease

● Chromophobe renal carcinoma – pale, eosinophilic cells