1) Nearly all renal diseases secondarily involve the renal blood vessels, with the main diseases affecting the kidneys' blood vessels being benign nephrosclerosis, malignant nephrosclerosis, and thrombotic microangiopathies. 2) Benign nephrosclerosis is characterized by hyaline thickening of small arteries and arterioles causing ischemic atrophy, while malignant nephrosclerosis features hyperplastic "onion skin" thickening of arterioles and fibrinoid necrosis. 3) Thrombotic microangiopathies include hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, characterized by microangiopathic hemolytic anemia

1. Diseases Involving
Blood Vessels of the
Kidneys

3. Presented By
Prof. Dr.
Nabil Tadros Mikhail
MBBS, MS Pathol., PhD Pathol.
Prof. of Pathology
Alexandria University - Egypt
Consultant & Chief Pathologist
King Fahad Central Hospital
Gizan - KSA

4. 

Nearly all renal diseases of the kidney
involve the renal blood vessels
secondarily.
However the main diseases affecting
blood vessels of the kidney are
1.
2.
3.
Benign nephrosclerosis ,
Malignant nephrosclerosis
Thrombotic microangiopathies.

5. Benign Nephrosclerosis

6. I- Benign nephrosclerosis



This lesion describe the renal changes
in benign hypertension.
Morphology:
The kidneys are symmetrically
atrophic with diffuse fine granularity.

7. 
Benign nephrosclerosis. The smaller arteries in the kidney have become
thickened and narrowed. (Hyaline arteriolosclerosis.) This leads to
patchy ischemic atrophy with focal loss of parenchyma that gives the
surface of the kidney the characteristic granular appearance
(symmetrical)

8.  Patchy ischemic atrophy with focal loss of parenchyma that gives
the surface of the kidney the characteristic granular appearance (symmetrical)
Slide 21.61

9. I- Benign nephrosclerosis




Microscopically: The basic changes is
Hyaline thickening of the wall of small
arteries and arterioles.
(hyaline arteriolosclerosis) .
Homogenous pink hyaline thickening
of vessel wall & narrowing of lumen.
This produces ischemic atrophy of
kidney

10. hyaline deposition, marked thickening of the walls
narrow lumen
Benign nephrosclerosis.
High power view of two arterioles with hyaline
deposition, marked thickening of the walls, and
narrow lumen.
Slide 21.62

11. II- Malignant Nephrosclerosis

12. II- Malignant nephrosclerosis



It is renal lesion associated with
malignant hypertension .
The latter is less common than benign
hypertension .
Occur in only in 5% of hypertensive
patients or may arise denovo.

13. Malignant hypertension




Pathogenesis:
The initial event appear to be some form
of vascular damage to the kidney.
This results in increase permeability to
fibrinogen and platelet deposition .
This lead to fibrinoid necrosis of
arterioles and platelet deposition,

14. Malignant hypertension



Pathogenesis:…
Mitogenic factors from platelets (PDGF)
cause intimal hyperplasia of vessels
resulting in hyperplastic arteriolosclerosis
typical of malignant hypertension.
The kidney is markedly ischemic and there
is increased level of renin and aldosterone

15. Malignant hypertension




Morphology:
The kidney is normal or slightly
shrunken.
Small pinpoint hemorrhage may
appear on cortical surface due to
rupture of arterioles .
It has flea bitten appearance.

16. 

In malignant nephrosclerosis.
The kidney demonstrates focal small pinpoint hemorrhages.
Giving a flee bitten appearance

17. Malignant hypertension



Microscopically:
Larger arterioles shows a characteristic
finding of hyperplastic arteriolosclerosis.
It show onion-skin concentric laminated
thickening of the wall of arterioles with
progressive narrowing of the lumen.

18. Malignant hypertension



Microscopically:
In addition, small blood vessel shows fibrinoid
necrosis and the wall show homogenous
granular eosinophilic appearance.
Also there is infiltration of inflammatory cells
giving rise to necrotizing arteriolitis which
may extend to glomeruli

19. 
Thickening of the arterial wall with malignant hypertension
also produces a hyperplastic arteriolitis The arteriole has
an "onion skin" appearance.

20. 
Malignant hypertension leads to fibrinoid necrosis of small
arteries as shown here. The damage to the arteries leads
to formation of pink fibrin--hence the term "fibrinoid

21. Malignant hypertension

Clinical picture:
It is characterized by

Marked elevation of blood pressure
(diastolic pressure more than 120 mm/Hg)




Papilledema
Encephalopathy
Renal failure
Cardiac abnormalities.

22. Malignant hypertension


Clinical picture:…
The common presenting symptoms are
related to increase of intracranial
pressure



Headache
Vomiting
Visual disturbances

23. Malignant hypertension


Malignant hypertension require
immediate treatment .
Death may occur particularly in those
without treatment, due to



Renal failure
Cerebrovascular accident
Cardiac failure.

24. III
Thrombotic microangiopathy

25. III- Thrombotic microangiopathy


These represent clinical syndrome
characterized by widespread thrombosis in
microcirculation and
clinically by




Microangiopathic hemolytic anemia,
Thrombocytopenia
In some cases renal failure.
These include hemolytic uremic syndrome and
thrombotic thrombocytopenic purpura.

26. III- Thrombotic microangiopathy
These include


Hemolytic uremic syndrome
Thrombotic thrombocytopenic purpura.

27. (Hemolytic Uremic Syndrome (HUS- 1
It can occur in adults or children.
A- adult HUS:
 It is usually due to damage of
endothelium as a result of exposure
to certain drugs or radiation


28. B- Children HUS



Most cases usually follow infectious
gastroenteritis cause by E coli strain
which elaborate toxins that produce
damage of endothelium .
This damage initiate platelet activation
and thrombosis.
Ingestion of infected meat (hamburger)
is a risk factor.

29. B- Children HUS

Clinically, there is



Later on



Bloody diarrhea ,
Hematemesis.
Oliguria and
Renal failure develop.
The disease is one of the main cause
of renal failure in children.

30. Thrombotic thrombocytopenic purpura
((TTP

TTP is another microangiopathy
characterized by its occurrence in
females mainly.




Thrombocytopenia,
microangiopathic hemolytic anemia ,
neurological symptoms and
renal failure may develop.
-2

31. Thrombotic thrombocytopenic purpura
-2
((TTP



Pathogenesis:
TTP is not due to endothelial damage
(unlike HUS)
TTP is due to deficiency of cleaving
protease enzyme (metalloprotease),
that normally degrade very high
molecular weight vonWillibrand factor
(vWF) .

32. TTP pathogenesis

In the absence of this enzyme vWF
accumulate in plasma and promote
platelet aggregation through out
circulation.

33. 
A small platelet-fibrin thrombus is seen in a glomerular capillary
above the arrow. This occurred in a patient with thrombotic
thrombocytopenic purpura (TTP).

34. 
A small platelet-fibrin thrombus is seen in a glomerular capillary
above the arrow. (MSB stain for fibrin)
Slide 21.65