11 - Vascular Diseases and Chronic Kidney Disease Flashcards
What are four renal vascular diseases?
- Hypertensive nephrosclerosis
- Renovascular HTN: renal artery atheroscleorsis, fibromusclar dysplasia
- Atheroembolic disease
- Thrombotic microangiopathy
What is hypertensive nephrosclerosis?
Chronic kidney disease in a pt with long-standing, poorly controlled HTN.
Typically evidence of other target organ damage as well - scarring of the kidney preventing normal filtering function.
Proteinuria often present.
What are morphological features hypertensive nephrosclerosis on gross and light microscopy?
Gross: normal to slightly small with finely granular subcapsular surface
LM: subcapsular glomerular sclerosis, tubular atrophy, initial fibrosis, arteriolar hyaline
What are morphological features of malignant HTN?
Mucoid intimal thickening (arteries)
Glomerular capillary wrinkling: constriction of afferent arteriole to avoid pounding from high BP
GBM duplication (similar to thrombotic microangiopathy (TMA))
What are causes of renovascular HTN?
Renal artery stenosis is a secondary cause of HTN with 2 main causes:
- atheroscleorsis in older people
- fibromuscular dysplasia in younger people, more commonly females
Trauma, dissection, extrinsic compression
What is the mechanism of HTN in renal artery stenosis?
Renin release converts angiotensinogen to angiotensin I.
ACE converts AngI to AngII, which causes vasoconstriction and aldosterone release.
This causes HTN.
In what pts should you suspect renal artery stenosis?
- Early or late onset HTN
- Difficult to control (many meds not helping)
- Abdominal or flank bruit
- Renal failure after starting ACE inhibitor (ACEs and ARBs treat chronic kidney fialure but can cause acute)
How do you dianose renal artery stenosis?
- CT with contrast
- MRA (MRI for BVs)
- Renal arteriography
- Doppler ultrasound
- Captopril renogram
- Renal vein renon sampling (renin will be high with unilateral stneosis)
What are the morphologic features of renal artery stenosis caused by atherosclerosis?
- stenosis usually in proximal renal artery
- Eccentric plaque with intimal fibrosis, cell debris, lipid and foam cells
- Medial and adventitial fibrosis
- Plaque may dissect of hemorrhage
- Calcification may occur
What are the morphological changes of renal artery stenosis caused by fibromuscular dysplasia (FMD)?
Usually in younger women.
Intimal, medial, and adventitial forms.
What arteries are commonly effected by fibromuscular dysplasia (FMD)?
Renal artery: 60-75% (bilateral in 35%)
Cervicocranial arteries: 25-30%
Visceral arteries: 9%
Extremity arteries: 5%
Two vascular beds involved in up to 28%
What happens to vessel walls in the medial fibroplasia form of fibromuscular dysplasia (FMD)?
- Alternating thinned media and thickening fibromuscular ridges
- Forms string of beads appearance radiographically.
- Beadining is larger than caliber of artery
- Middle to distal artery
What is the treatment for renal artery stenosis?
- Surgical revascularization
- Angioplasty and stenting
- Medical management only
You also need to fix implications: HTN
Stenosis itsenf needs surgical intervention
What are three thromboembolic diseases that impact the kidneys?
- Cortical infarcts
- Renal cholesterol microembolism synrome
- Thrombotic microangiopathy
What are morphological features of a cortical infarct?
Renal artery occlusion causing extensive parenchymal infarction.
Smaller branch: wedge-shaped infarct causing pale hyperemic border, coag necrosis, and hemorrhage and acute inflammation at edge (from damaged tissue)
Fibrotic (later)