1. Renal Vascular Diseases
GENERAL OUTLINE
I. Hypertension
“Benign” Nephrosclerosis
“Malignant” Nephrosclerosis
Renal Artery Stenosis
Thrombotic Microangiopathies
Miscellaneous Vascular Diseases
HYPERTENSION
Definition: diastolic > 90 mm Hg or systolic > 140 mm Hg
pre-hypertension: 120/80 – 139/89
Prevalence:
20-25% population
4th and later decades
60% population after age 70
Approximately 72 million in US
Complications: CVA, LVH and CHF, coronary
artery disease, renal disease

2. TYPES OF HYPERTENSION
Primary Hypertension (Idiopathic) (could be genetic/polymorphisms w/mutations of Na Channels ( %)
Secondary Hypertension (5 - 10%)
Renal
Acute Glomerulonephritis
Chronic Renal Disease
Polycystic Disease
Renal Artery Stenosis
Renal Vasculitis
Renin-producing Tumors (Juxtaglomerular Tumor)
BP:
Regulated by adjustments to CO and peripheral resistance. CO is influenced by blood volume. Blood volume is controlled by Na concentrations which is a major function of the kidney!
Endocrine
Cardiovascular
Neurologic
Primary (aka essential) hypertension is probably due to a combination of genetic factors and environmental factors:
genetic; environmental; habits such as smoking, diet, alcohol; occupation; living conditions; and a host of other factors
Essential hypertension is mainly treated by adjusting these factors, for example, reducing dietary intake of salt, performing moderate exercise, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
Consequences of HTN:
Cardiac disease and stroke
Renal and retinal disease (half die of cardiac disease, 15% cerebrovascular accident, 10% renal failure)
HTN  primary renal injury  ESRD

3. Renal Vascular Diseases
Chronic “Benign” Nephrosclerosis
Definition
Sclerosis of small arteries/arterioles w/ attendant renal parenchymal (glomerular and tubulointerstitial) changes.
Clinical Features
Mild sustained hypertension of long duration.
Pathogenesis
Hemodynamic changes, genetic defects or both resulting in abnormalities in the wall of small arteries and arterioles (medial and intimal thickening, hyaline deposition).
Pathology
Gross: finely granular contracted kidney. Shallow scars, thinned cortex.
Microscopic:
medial, intinal fibrotic thickening of small arteries. Reduplication of lamina elastica interna, medial hypertorphy w/ luminal narrowing.
Hyaline deposition in arterioles (accumulation of plasma proteins in BM) w/ loss or displacement of smooth muscle
Glomeruli w/ ischemic collapsing changes or global glomerulosclerosis (BM is wrinkled)
Tubular atrophy and interstitial fibrosis
Course
Renal insufficiency/failure if hypertension is prolonged, or if superimposed upon an underlying disease (diabetes).
African-Americans more susceptible to develop ESRD.
Primary (aka essential) hypertension is probably due to a combination of genetic factors and environmental factors:
genetic; environmental; habits such as smoking, diet, alcohol; occupation; living conditions; and a host of other factors
Essential hypertension is mainly treated by adjusting these factors, for example, reducing dietary intake of salt, performing moderate exercise, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
Primary (aka essential) hypertension is probably due to a combination of genetic factors and environmental factors:
genetic; environmental; habits such as smoking, diet, alcohol; occupation; living conditions; and a host of other factors
Essential hypertension is mainly treated by adjusting these factors, for example, reducing dietary intake of salt, performing moderate exercise, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are: Renovascular Disorder, Renal Parenchymal Disease, Coarctation of the Aorta, Pheochromocytoma , Pregnancy Induced Hypertension.

4. Renal Vascular Diseases
“Malignant” Nephrosclerosis
Definition
Severe hypertension
Systolic >200 mm Hg, diastolic > 120 mm Hg
Acute tissue injury in multiple organs
Clinical Features
Men > women, around 40 years of age. (seen more in young African A. males)
Prior history of essential hypertension
HTN BP>200/130
papilledema, retinal hemorrhage
neurologic symptoms, hematuria, proteinuria, headache, congestive heart failure
acute renal failure
Pathogenesis
Unknown
Vascular chagnes due to preceding HTN complicated by renal ischemia, microvascular vasoconstriction  endothelial injury and activation of RAAS.
Most patients have high plasma renin.
Pathology
Gross: variable size, petechial subcapsular hemorrhage, mottling, occasional infarcts
Miccroscopic:
Fibrinoid necrosis of arteriles
Intimal edema
hyperpalstic arteriolar changes (“onion skinning”) in chronic injury
glomerular chagnes (necrotizing glomerulitis
thickening and wrinkling of glomerular capillary from hypoperfusion
Thrombosis of small vessels and capillaries.
Course
A medical emergency. Unattended patients may succumb to CVA, ARF or CHF within wks or mo.
Treated, 75% will survive 5 yrs. Recovery may occur with renal dysfunction.
PETECHIAE
Wrinkled Glomerulous
ONION SKIN
LESION
gen, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
FIBRINOID
NECROSIS
FIBRINOID
NECROSIS
THROMBOSIS
Young black men most commonly affected. Also women with toxemia of pregnancy, or persons with renal artery stenosis. Autoimmune diseases can also associate with mHtn.

5. RAS - Hyperplasia of JGA
Renal Vascular Diseases
Renal Artery Stenosis
Definition
Renal disease associated w/ stenosis of renal artery. 2-5% of hypertension
Clinical Features
2-5% of hypertension.
HTN in young (fibromuscular dysplasia), or senior adults (atheromatous plaque) w/ preserved renal function.
Usually unilaterial w/Bruit.
Confused with essential HTN in adults .
Renal angiogram is diagnostic and can stent open.
Kidney on side of stenosis is small.
Plasma renin increased due to hypersecretion from stenotic side.
Pathogenesis
Goldblatt type hypertension
Ischemia activates renin-angiotensin system
Causes:
Atherosclerotic (senosis)
Fibromuscular dysplasia (Intima, Media, Adventitia)
Arteritis
Arterial dissection
Pathology
Stonotic side: kidney is grossly small but smooth. Diffuse ischemic atrophy of tubules and interstitium w/crowding of glomeruli.
Contrlateral Kidney: Features of benign nephrosclerosis
Course
Unattended progressive loss of renal function (stenotic side).
Features of hypertension on contralateral
Nephrectomy, angioplasty curative ( %).
RAS - Hyperplasia of JGA
Renal
Atrophy
gen, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
STENOSIS
RAS - Atherosclerosis
Crowded Glomeruli

6. Renal Vascular Diseases
Thrombotic Micro-angiopathies
Definition
Group of renal diseases having in common thrombosis of small arteries and capillaries with microangiopathic hemolytic anemia and renal insufficiency or renal failure
Clinical Features
Classic HUS: Childhood hemolytic uremic syndrome (HUS) (infectious; E.coli O157:H7) (GI infection w/microganiopathic anemia, renal involvement, renal failure.
Adult HUS: (infections E.coli, shigella, drugs, anti-phospholipid Ab, hypercoagulable)
Familial HUS: mutation in Factor H
Idiopathic Thrombotic Thrombocytopenic Purpura (TTP) systemic thrombotic and purpuric lesions, neurlogical symptoms predominate
Pathogenesis
Endothelial injury and activation, platelet aggregation and vascular thrombosis and/or vasospasm
HUS - Shiga toxin (injury to endothelial cell and platelet activation) associated with decreased fibrinolysis
TTP – Inherited mutation of Factor H. Other cases have unusually large von Willebrand factor; metalloproteinase deficiency (ADAMTS13)
Pathology
Acute phase dominated by thrombotic changes, and chronic with vascular repair/remodeling
Thromboic changes and fibrin depostion in wall of interlobular ateries, afferent and glomerular capillaries (double contour appearance)
Organizing/remodeling chagnes in intralobular arteries, afferent and flomerular capillaries
Cortical necrosis/infarcts
Course
Renal failure requiring dialysis
Long term prognosis depends on extent of initial injury & adequacy of management
1/3 of patients recover renal function and 1/2 go into CRF
TTP requires plasmapheresis to remove large von Willebrand factors
Recent
Old
Infarcts
gen, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
Organizing
Thrombosis
Organizing
Thrombosis
Glomerular
Thrombi
Childhood HUS: verotoxin from E. Coli
Adult HUS: causative agent varies – infections, chemo, radiation, pregnancy related, anti-phospholipid antibodies.
Familial HUS: mutation in Factor H
TTP: deficiency of metalloproteinase for von Willebrand factor
Helmet
Burr

7. Sickle cell nephropathy Atheroembolic Renal Disease
OTHER MISCELLANEOUS Renal Vascular Diseases
Renal Embolism
Secondary to heart/valvular disease, aortic catheterization, or trauma
Small are asymptomatic but large result in hematuria or occlusion.
Cause renal infarctions from inconsequential to loss of kidney (arterial is pale, venous is hemorrhagic)
Atheromatous embolization results in occlusion of smaller vessels by embolic material (fiberous deposit post occlusion) followed by giant cell reaction within two week.
Infective endocarditis may cause septic embolization and renal infection, pyelonephritis.
Sickle Cell Nephropathy
Homo or heterozygous individual with hematuria and progressive decrease in concentrating urine due to sickling of red cells (perticularly in hypozic renal medulla)
Intravascular thrombosis results in glomerular changes (focal segmental glomeruloscelerosis and less common membranoproliferative glomerulonephitis), ischemic scarring of medulla, infarcts and papillary necrosis
Can cause proteinuria or hematuria
Prone to medullary fibrosis.
Iron deposits from hemolysis
Sickle cell nephropathy
Cholesterol
Clefts
gen, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
Atheroembolic Renal Disease
Segmental sclerosis
Infarct
Ischemic
Old
Hemorrhagic
Recent
Medullary
Fibrosis

8. OTHER MISCELLANEOUS Renal Vascular Diseases
Cortical Necrosis
Ischemic necrosis or part of all of the renal cortex secondary to thrombosis and/or vasospasm associated with shock, sepsis, obstetric emergencies (blood loss), and trauma.
Intravascular thrombi may be present
Diffuse: permanent renal failure will result.
Focal: reanl function will be predicated on extent of involvement
Infarct in cortex can lead to ESRD
Pale/Homogeneous necrosis of cortical membrane
gen, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.

9. OTHER MISCELLANEOUS Renal Vascular Diseases
Renal Artery Thrombosis
Usually complication of atherosclerosis, vascular surgery (correction of stenosis, renal transplant, dissecting aneurysm or aorta, and rarely arteritis).
Partial Thrombosis  flank pain, hematuria, w/ HTN to follow.
Complete Occlusion (and bilateral involvement)  anuria followed by acute renal failure. Surgery may salvage kidney.
Renal Vein Thrombosis
Unilateral or bilateral, renal vein thrombosis is a complication of hypercoagulable states
Prone to occur in patients with nephrotic syndrome (40%)
Can occur in patients with retroperitoneal infection or tumor, trauma, pancreatitis, and severe dehydration in young children.
Hematuria, anuria, and acute renal failure can be presenting symptoms.
Grossly large, swollen, hemorrhagic
Micro vascular congestion, edema, hemorrhage
gen, improve living conditions and in unresponsive cases, supplemented by antihypertensive drugs such as diuretics and ACE inhibitors.
The main causes of secondary hypertension are:
Renovascular Disorder,
Renal Parenchymal Disease,
Coarctation of the Aorta,
Pheochromocytoma
Pregnancy Induced Hypertension.
Renal Vein Thrombosis