Renal pathology Flashcards
What is the functional unit of the kidney?
Nephron
What does the nephron consist of?
Renal corpuscle (glomerulus w/ Bowman’s capsule)
PCT
Loops of Henle
Distal tubules
Collecting ducts
Discuss the clinical presentation of patient’s with renal disease
Proteinuria (nephrotic syndrome)
Haematuria (nephritic syndrome)
Systemic hypertension
Renal failure
UTIs
Nephrolithiasis
Renal tubular defects
What is proteinuria?
> 30mg/24h (adults)
100mg/m2/24h (children)
What are features of nephrotic syndrome?
Heavy proteinuria (>3.5g/24h)
Generalised edema
Hypoalbuminemia
Hyperlipidemia
What are the types of haematuria?
Macroscopic vs microscopic
Intermittent vs persistent
What are non-haematuria causes of red urine?
Foods (beets, blackberries, rhubarb)
Medications (rifampicin, laxatives)
Poisons (lead, mercury)
What is the pathophysiology of haematuria?
Glomerular disease -> dysmorphic RBCs in urine
What are the features of nephritic syndrome
Acute onset haematuria
Oliguria
Systemic hypertension
+/- peripheral edema
+/- proteinuria
What are the pathogenetic mechanisms of glomerular inflammation?
Majority are immune mediated
- immune complex formation and deposition
- non immune complex mediated (lymphokines, cytokines)
What kinds of antigens are involved in antigen-antibody complex formation?
Planted antigens
Fixed antigens
Which primary renal diseases result in nephrotic syndrome?
Minimal change disease
Focal segmental glomerulosclerosis
Membranous glomerulosclerosis
Membranoproliferative glomerulosclerosis
Which primary renal diseases result in nephritis syndrome?
Diffuse proliferative
Mesangioproliferative
Thin basement membrane disease
Anti-GBM disease
Focal segmental proliferative
Which systemic diseases involve the renal system?
DM
SLE
Amyloidosis
Infections (HIV, malaria, hepatitis)
Drugs (heroin)
What is the most common cause of nephrotic syndrome in children?
Minimal change disease
What is minimal change disease associated with? (minority of cases)
Infections
Immunisation
Drugs
Neoplasia
Discuss the aetiology of minimal change disease
Immunologic (lymphokine/cytokine)
Not immune-complex mediated
Discuss clinical features of minimal change disease
Caucasian > black
M > F
Proteinuria
Responsive to steroids
How does minimal change disease appear on histology?
Light microscopy - normal
IF microscopy - normal
Epithelial cell foot process effacement on ultrastructural examination
What is the epidemiology of focal segmental glomerulosclerosis with hyalinosis?
Adult > children in NS
Black patients
Increasing with HIV
Discuss the aetiology of focal segmental glomerulosclerosis
Lymphokine/cytokine
Not immune-complex mediated
How does focal segmental glomerulosclerosis appear on histology?
Focal lesions (<50% glomeruli involvement)
Segmental lesions
Loss of capillary loop patency
Glomerular tuft sclerosis
Epithelial cell foot process effacement
What is the prognosis of focal segmental glomerulosclerosis?
Poor response to steroids
50% progress to chronic renal failure
Disease recurs in renal transplants
Discuss the aetiology of membranous glomerulnephritis
Immune-complex mediated
Ag-Ab complex deposition in relation to glomerular BM (sub-epithelial)
Name causes of membranous glomerulonephritis
85% idiopathic (primary)
Infections
Drugs
Tumours
Auto-immune disease
Name infectious causes of membranous glomerulonephritis
HBV
Malaria
Syphilis
Bilharzia
Name toxin causes of membranous glomerulonephritis
Gold
Mercury
Heroin
Name neoplastic causes of membranous glomerulonephritis
Carcinoma
Melanoma
Lymphoma
Name auto-immune disease causes of membranous glomerulonephritis
SLE
Discuss the features of membranous glomerulonephritis on histology
Glomerular BM changes
- diffuse spike formations
- subepithelial deposits
No cellular proliferation
Discuss the prognosis of membranous glomerulonephritis
Adults - majority unresponsive to therapy and progress to chronic RF
Children - better prognosis, 10% to chronic RF
Discuss the aetiology of membranoproliferative glomerulonephritis
Immune-complex mediated
Ag-Ab complex deposition in relation to glomurular BM (sub endothelial) and within the mesangium
What is the difference in the Ag-Ab complexes in membranous glomerulonephritis and membranoproliferative glomerulonephritis
Membranous - subepithelial
Membranoproliferative - subendothelial
Discuss the features of membranoproliferative glomerulonephritis on histology
Diffuse proliferative process
Crescentic
Distinctive glomerular BM changes
- increased mesangial cellularity
- double contour ‘tram tracks’
Discuss the prognosis of membranoproliferative glomerulonephritis
Poor
Majority progress to CF
Discuss the aetiology of post-infectious glomerulonephritis
Diffuse proliferative glomerulonephritis
Ag-Ab complex deposition following a transient infection
Which organisms can result in post-infectious glomerulonephritis?
Bacteria
- BHS
- staph
- meningo
- pneumo
Viruses
Malaria
Bilharzia
Toxoplasmosis
Discuss the features of post-infectious glomerulonephritis on histology
Diffuse proliferative glomerulonephritis
Large subepithelial humps
What is the prognosis of post-infectious glomerulonephritis?
Generally good
What is mesangioproliferative glomerulonephritis?
A heterogeneous group of diseases including SLE and IgA nephropathy
Discuss the causes of mesangioproliferative glomerulonephritis
Majority = idiopathic
Autoimmune (SLE)
Infectious (HBV, bilharzia)
Drugs
Neoplasm (carcinoma, malignant, lymphoma)
What are the 3 main kidney lesions in HIV renal disease?
HIV associated nephropathy (HIVAN)
HIV immune complex kidney disease (HIVICKD)
Thrombotic microangiopathy
What are the histological features of thrombotic microangiopathy?
Intimal swelling
Arteriolar thrombi
Fibrinoid material in vascular lumina
Which genes are implicated in HIVAN?
APOL1
MYH9
(African descent)
Discuss the clinical presentation of HIVAN
Acute onset proteinuria
Progressive renal insufficiency
Hypoalbuminemia
Minimal peripheral edema
BP normal
Enlarged kidneys
Discuss the histological features of HIVAN
Pan-nephropathy (collapsing variant of FSGS)
Microcystically dilated tubules
Interstitial inflammation and fibrosis
What is the prognosis of HIVAN?
Poor
In which amyloidosis types is renal involvement common?
AL
AA
Discuss the histological features of amyloidosis
Extracellular deposits within the glomerulus, around blood vessels and within interstitial
Discuss the pathogenesis of diabetic glomerulopathy
Increased GMB permeability -> excess collagen IV deposition -> protein glycosylation -> hyperinfiltration
Discuss the histological features of diabetic glomerulopathy
Capillary wall thickening
Mesangial expansion
Kimmelstiel Wilson lesion
