TOPIC 12: vascular diseases of the kidney

Question 1

RENAL ARTERIES:large vessel vasculitis

two types, some symptoms, age differences

Answer 1

1. giant cell(temporal) arteritis
   - granulomatous inflammation of aorta and major branches -often the superficial temporal artery
   - patients >50 years old
   - ->headache
   - ->temporal artery tenderness(when combing hair)
   - -> jaw claudication
   - ->sudden blindness usually in one eye
   - typical 2 year course, then complete remission
2. takayasu arteritis
   - granulomatous inflammation of the aorta or major branches
   - often in patients <50 years old

Question 2

RENAL ARTERIES:medium vessel vasculitis (2)

Answer 2

1. polyarteritis nodosa (PAN)
   - necrotizing vascilitis
   - causes aneurysms and thrombosis- infarction in affected organs
   - ->predominantly skin (rash and punched out ulcers)
   - ->renal disease( main cause of death)
   - -> cardiac, GI, GU symptoms
2. Kawasaki disease
   - childhood variant of PAN
   - affects coronary arteries (aneurysms)
   - causes lymph node enlargement

Question 3

RENAL ARTERIES:small vessel vasculitis (6)

Answer 3

1. microscopic polyangitis
   - ANCA in 70%
   - antigen is MPO
   - bleeding in the lungs
   - RPGN in kidneys
2. wegener’s granulomatosis
   - ANCA in 85%
   - antigen is PR3
   - Granulomas and necrosis in upper airways
   - infiltration, granulomas & bleeding in lungs
   - RPGN in kidneys
3. churg strauss syndrome
   - ANCA in 50%
   - antigen is MPO
   - allergic rhinitis (upper airways)
   - asthma (lungs)
   - RPGN in kidneys
   - eosinophilia
4. henoch- schölein purpura
   - IgA immune complex deposits
   - mainly affect: skin,GI, glomeruli, joints
   - renal manifestations: nephritis sy or isolated hematuria
5. goodpasteur syndrome
6. cryoglobinemia
   - MPGN (nephritic syndrome)

Question 4

RENAL CAPILLARIES: HNS & TMA

Answer 4

1. hypertensive nephrosclerosis (HNS)
   - Long standing benign hypertension–> slow, progressive loss of renal function
   - histo: 1)afferent arteriolar thickening&hyalinization
   2) glomerulosclerosis
   3) interstitial inflammation& fibrosis
   - other organs affected: LVH, retinal changes, microalbuminuria
2. thrombotic microangiopathies(TMA)
   - group of acute syndromes including:
   1) microangiopathic hemolytic anemia (MAHA)
   2) Thrombocytopenia
   3) AKI
   4) CNS abnormalities
   - all share common pathophysiology:
   1) an event triggers thrombosis
   2) platelet consumption
   3) fibrin strand deposition
   4) mainly in the renal vasculature–> mechanical destruction of passing RBCs
   - include:
   1) hemolytic uremic syndrome(HUS)
   2) thrombotic thrombocytopenic purpura( TTP)
   3) Transplant nephropathy
   4) radiatino nephropathy
   5) scleroderma crisis
   6) malignant HTN
   7) antiphospholipid syndrome
   8) HELLP syndrome

Question 5

HUS (sy, treat, prog)

Answer 5

• Due to e.coli strain 0157 that produces the Shiga Toxin that attacks endothelial cells
• typically affects young children <10 after eating undercooked meat
• atypical cases can be caused by complement component deficiencies

symptoms:

1) abdominal pain
2) bloody diarrhea
3) AKI- hematuria and proteinuria
4) blood film: fragmented RBCs (schistocytes), decreased PLT count and decreased HB
5) normal clotting tests

Treatment:

• dialysis may be required in case of AKI
• plasma exchange used in severe persistent disease

prognosis:

• worse in non e.coli cases
• mortality 3-5%
• good prognosis if caught early

Question 6

TTP (sy, treat)

Answer 6

• genetic or acquired deficiency of ADAMTS13
• this normally cleaves multimers of VWF
• VWF large multimers formed causing PLT aggregation and fibrin deposition in small vessels leading to microthrombi.

symptoms:

1) MAHA
2) low PLT
3) AKI
4) Flunctuating CNS signs (seizure)
5) fever

Treatment:

• urgent plasma exchange (TTP is a hematological emergency)
• eculizumab, rituximab

Question 7

RENAL VEINS: renal vein thrombosis (RVT) -chronic and acute, sy, diag, treat

Answer 7

• Chronic RVT usually asymtomatic ( happens in nephrotic syndrome or renal malignancy and may worsen proteinuria and renal function)
• Acute RVT may result from trauma, dehydration or hypercoagulable state

symptoms:

1) flank pain
2) hematuria
3) increased LDH
4) proteinuria
5) renal failure (if bilateral)

diagnosis:

1) US
2) MR
3) CT
4) venography

treatment:

1) LMWH followed by anticoagulation therapy for 6-12 months
2) in acute: catheter thrombectomy
3) prophylactic anticoagulation is recommended in high risk pts (low albumin, heavy proteinuria)

Question 8

RENAL ARTERIES: RAS

causes, hemodynamic cons.,sy, tests, treat

Answer 8

renal artery stenosis

causes:

1) atherosclerosis (65%): elderly, comorb eg IHD stroke or PVD
2) Fibromuscular dysplasia (35%): younger than 55
3) rarely: takayasu, thromboembolism, external compression, APS, after transplant

hemo changes:
decreased perfusion–>decreased GFR–> RAAS activation–> Systemic HTN

Signs:

1) rapid onset HTN resistant to treatment
2) worsening renal function after ACEi (in bilateral artery stenosis)
3) pulmonary edema (‘flash’ pulm edema)
4) bruits and weak leg pulses

test:

1) US: renal asymmetry(affected side smaller)
2) doppler US (renal blood flow disturbance)
3) CT/MR more sensitive but contrast nephropathy
4) RENAL ANGIO is the ‘GOLD STANDARD’ but do after CT/MR bec it’s invasive

treat:
1)ANTIHTN therapy:
(ACEi, Ca channel blockers, diuretics, statins, aspirin)
2) transluminal angioplasty and stent placement

Question 9

RENAL ARTERIES: Cholesterol Embolism

Answer 9

• lodge of an embolism in distal microcirculation
• inflammatory response
• after endovascular procedures such as arterial cathetirisation

sy:

1) fever, myalgia, eosinophilia (due to inflammatory resp)
2) uncontrolled BP
3) oliguria and AKI

4) livedo reticularis
5) gangrene
6) GI bleeds