Pathology 7 Flashcards
What is benign nephrosclerosis?
Sclerosis of renal arterioles and small arteries
What is benign nephrosclerosis associated with?
Some degree of ischemia –> This causes release of renin in response to the decrease in blood flow (HYPERTENSION)
What renal changes are seen in association with benign hypertension?
Hyaline arteriosclerosis
Where does hyaline deposit in benign nephrosclerosis?
Arterioles
-Get extravasation of plasma proteins through injured endothelial cells (also in BM)
With benign hypertension do you see renal insufficiency or uremia?
Not in uncomplicated cases
Which patient population has more severe blood pressure elevations that increase the risk of renal insufficiency?
Diabetes and African Americans
With benign nephrosclerosis what are the kidneys like?
They are atrophic
What 2 other diseases are seem simultaneously with benign hypertension
- Diabetes (Why we give ACEi to protect kidneys… they dilate efferent arteriole)
- Fibromuscular dysplasia
What are the clinical symptoms of benign nephrosclerosis?
- Mild oliguria
- Loss of concentrating mechanism
- Decrease GFR
- Mild degree of proteinuria is a constant finding
What usually kills patients with benign nephrosclerosis?
Hypertensive heart disease or cerebrovascular disease (not renal disease)
What is the pathogenesis associated with benign nephrosclerosis?
Medial and intimal thickening
What is seen in elderly patients (with or without HTN or diabetes) and in patients with long-standing diabetes, but most common and most severe in HTN patients?
Hyaline arteriolosclerosis
Is malignant hypertension more common than benign nephrosclerosis?
NO, less common
What 2 circumstances might malignant hypertension arise from?
- Novo (without pre-existing HTN)
2. Suddenly in patient with mild HTN (essential benign HTN)
What is the initial event in malignant HTN?
Some form of vascular damage to the kidney
What does vascular damage to the kidney result in?
Increased permability of small blood vessels to fibrinogen and other plasma proteins, endothelial injury, and platelet deposits
In malignant HTN what does increased permability of small blood vessels result in?
The appearance of fibrinoid necrosis in small arteries and arterioles and intravascular thrombosis
What does fibrinoid necrosis and intravascular thrombosis lead to?
Intimal hyperplasia of the vessels resulting in hyperplastic arteriosclerosis (MALIGNANT HTN)
What is the self-perpetuating cycle seen in malignant hypertension?
Narrowing of renal afferent arteriole (progressive ischemia) stimulates angiotensin II production with increased renin secretion (aldosterone will increase too)
-Constriction (angiotensin II) –> Vasoconstriction –> Ischemia –> Renin
What symptoms are seen with malignant HTN?
- Diastolic pressure over 130mmHg
- Papilledema
- Encephalopathy
- CV disorders
- Renal failure
What are the early symptoms due to in malignant hypertension and what are these symptoms?
Increased ICP - Headache, N/V, visual
What is hypertensive crisis?
- Loss of consciousness, convulsions
2. Proteinuria and hematuria (90%)
What is the frequent cause of death in malignant hypertension?
Uremia
What % of deaths from malignant HTN are due to CV or cerebral disorders (hemorrhage)?
10%
Describe the arteriolar wall in malignant HTN
- Has hyperplastic arteriolosclerosis
- Wall is thick, narrowed lumen
- Concentric circles
True or False: Unilateral renal artery stenosis is an uncommon cause of HTN
TRUE
What is renal artery stenosis commonly caused by?
Atheromatous plaque at the origin of the renal artery (70%)
What is the second leading cause of renal artery stenosis?
Fibromuscular dysplasia of the renal artery (hyperplasia of all the layers)
Which patient populations more frequently get renal artery stenosis due to fibromuscular dysplasia of the renal artery?
- Women
2. Younger (20-30)
Is renal artery stenosis cause a curable form of HTN?
Yes… it is related to the degree of stenosis
What is the cause of HTN in renal stenosis?
Renin secretion
What can be used to decrease HTN due to renal stenosis?
ACE Inhibitors… they show marked decrease in arterial BP
What is seen in the kidney suffering from renal artery stenosis?
That kidney is ischemic and shows signs of diffuse ischemic atrophy
In patients with renal artery stenosis, what does their presentation minic?
Essential HTN
What technique is required to localize the stenotic lesion?
Ateriography
What is the cure rate for renal artery stenosis?
70-80%
What type of emboli can be seen in renal artery stenosis?
Cholesterol emboli (causes platelet aggregation and occasional mononuclear cells)
What is thrombotic microangiopathies?
Widespread thrombosis in microcirculation causing damage to endothelial cells
What 2 diseases are associated with thrombotic microangiopathies?
- Childhood hemolytic-uremia syndrome (HUS)
2. Thrombotic thrombocytopenia purpura
What is one of the main causes of acute renal failure in children?
Childhood hemolytic-uremia syndrome
What is seen in the vessels in thrombotic microangiopathies
They vasoconstrict
What mediates vasoconstriction seen in thrombotic microangiopathies?
- Decrease NO
- Increased endothelin-1
- Decreased PGI2
What is characteristically seen in microangiopathic disorders?
Platelet-fibrin thrombi in the glomerular capillaries
What are the 2 predominant factors seen in thrombotic microangiopathies?
- Endothelial injury and activation, leading to vascular thrombosis
- Platelet aggregation