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Flashcards in Vascular disorders of the kidney Deck (25)
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1
Q

List the vascular disorders

A

Arterial:

  • Renal Artery Stenosis - the most frequent one
  • Cholesterol embolisation
  • Vasculitis

Capillary:
Thrombotic microangiopathies
- HUS, Hemolytic uremic syndrome
- TTP, Thrombotic thrombocytopenic purpura

Veins:
- Renal vein thrombosis

2
Q

Mechanisms of renal artery stenosis

A

65% - Atherosclerosis, age related

35% - Fibromuscular dysplasia

rare causes:
Aortic aneurysm or dissection
External compression, malignancy
Takayasu arteritis

3
Q

Describe fibromuscular dysplasia

A

non-atherosclerotic, non-inflammatory blood vessel constriction. (idk wtf its called fibromuscular, it just affects arteries)

Caused by abnormal, non-neoplastic growth of the intima, media, or pararterial tissue of a vessel.

Most commonly occurs in females, under the age of 50.

Occurs distally in the Renal Artery, as opposed to atherosclerotic stenosis, which usually occurs very proximal to the aorta.

Can affect any artery, but most commonly the renal and carotids.

Causes secondary hypertension due to RAAS activation of the kidneys.

Usually affects multiple spots, creating a beaded appearance on the artery, with alternating stenosis and aneurysm.

4
Q

Unilateral Stenosis,
features,
effects of RAS blockade

A

Plasma renin activity is high

RAS blockade reduces blood pressure acutely,
Increased lateralization of lab tests (lateralization of Renin expression)
GFR may drop precipitously in stenosed kidney, lowering overall function.

5
Q

Bilateral Stenosis, RAS blockade

A

Normal or low plasma renin activity

Blood pressure only drops after volume is reduced,
May lower GFR.

6
Q

Symptoms and signs suggestive of renal artery stenosis:

A
  • Sudden onset of hypertension and age under 50 years
  • Sudden onset of hypertension with diffuse atherosclerosis
  • Therapy resistant hypertension
  • Abdominal bruit
  • Decreasing renal function with unclear cause
  • Renal function deteriorated by ACE-Is or ARBs.
  • Size difference between kidneys >1cm
  • Hypokalemia of unknown origin - excessive RAAS
  • Peripheral artery disease
  • Atherosclerotic retinopathy
7
Q

Diagnosing RAS

A

CT-angiography - contrast contra’d less than 3GFR, hydration if >60.

Duplex ultrasound

MR-Angiography- no contrast if eGFR <30ml/mg

Captopril renography - aka Renal scintigraphy,
pre and post- ACE-I administration
ACE-I will significantly reduce flow to the stenosed kidney in unilateral stenosis.

8
Q

Renal artery stenosis therapy

A

Angioplasty and stenting
or Surgical revascularization

Control hypertension:
CCBs
Diuretics
BBs
Alpha blockers

Control atherosclerosis risk:
Statins
Antiplatelet drugs

9
Q

Complications of Revascularisation in renal artery stenosis

A

Just angioplasty has fewer complications than stenting

Stenting
Results are not great, ‘dubious’ according to lecture
May worsen daibetes

Cholesterol embolisation
Arterial dissection, thrombosis, occlusion

Contrast induced nephropathy

10
Q

When is surgical revascularization indicated and what are its comlications

A

indications:

  • Aortic aneurism
  • Aorto-illiac stenosis
  • Multiple stenoses,
  • Fibromuscular dysplasia with large aneurysms

Complications
Artery dissection
Acute vascular occlusion
General surgery complications, is a major vascular surgery, significant risk and expense.

If successful in well-selected cases, significant blood flow improvement and 80% survival at 5 years.

11
Q

Indications for renal revascularization

A

Sudden, rapidly worsening renal function due to stenosis

Therapy resistant severe HTX

Pulmonary edema and HTX

12
Q

Cholestrol embolisation, causes

A

Spontaneously from significant atherosclerosis

After major surgery or endovascular intervention
Immediately or 1-3 days later.

13
Q

Cholesterol emoblisation, presentation

A
Multi-organ involvement
Livedo Reticularis
Blue toe syndrome, necrosis of the extremities
Bowel Ischemia and necrosis
Acute Kidney Injury
Acute pancreatitis

Fever
Nausea
Leg/flank pain

labs
Eosinophiluria
Low complement

Definitive diagnosis by histology, with arterioles containing thrombosed regions with cholesterol clefts or biconvex gaps that are empty due to cholesterol washout on slide preparation.

14
Q

Cholesterol embolisation treatment

A

ACE-I’s
Corticosteroids
Statins

do NOT give anticoagulants.

15
Q

What are the thrombotic microangiopathies,

what are their common features

A

TTP and HUS

Acute disorders, in

Thrombocyte activation and thrombocytopenia, with impaired micro circulation from small vessel/capillary thrombi formation.

Hemolytic anemia,
Generation of Schistocytes
Increased LDH, 
Increased Bicarb
Decreased haptoglobin
16
Q

What causes TTP?

A

Acquired defect in the level or activity of ADAMTS13 metalloprotease
from autoantibodies against it.

Decreased cleavage of ultralarge vWF.
Increased circulating vWF.
Excessive systemic thrombocyte activation and depletion.

17
Q

What causes HUS

A

Usually E. coli O157:H7 strain, carrying shiga-like toxin

Sometimes Shigella dysenteriea

18
Q

The two types and presentations of HUS

A
d-HUS: Diarrheal HUS
shigatoxin or shiga-like toxin induced endothelial damage
- bloody dysentery
- AKI about 1 week later
- 30% also have neurologic symptoms

a-HUS: atypical HUS
very rare,
idiopathic, genetic, or autoimmune disorder causing chronic complement system activation.
- AKI with no diarrhea
- multiorgan involvement, but especially kidneys
Rx: plasmapheresis and eculizumab - complement C5 inhibitor.

19
Q

HELLP syndrome

A

Severe pre-eclampsia
Hemolysis and thrombopenia

Hemolysis, Elevated Liver enzymes, and Low Platelet sydrome.

Life threatening.

20
Q

Suystemic disorders that can cause thromboti microangiopathy

A

Antiphospholipid syndrome of SLE

Scleroderma

Malignant hypertension

Metastatic gastric cancer

21
Q

Drug induced TMA

A

Chemotherapy agents
Calcinuerin inhibitors

somehow clopidogrel

22
Q

Renal vein thrombosis risk factors

A

Chronic renal vein thrombosis:

  • Nephrotic syndrome
  • Renal tumors

Acute

  • Trauma
  • Dehydration
  • Hypercoagulable states
23
Q

Symptoms of acute and chronic renal vein thrombosis

A

Chronic: often asymptomatic, but causes chronic congestion/ischemia, and eventual renal fibrosis/ESRF

Acute:
Flank/loin pain
Hematuria
Increased LDH
Proteinuria

Bilateral acute:
AKI and oligo/anuria

24
Q

Renal vein thrombosis diagnosis

A

Duplex ultrasound
Spiral CT

MRI
Venography

25
Q

Renal vein thrombosis treatment

A

Prophylatic anticoagulation in all nephrosis patients
also in patients with severe hypoalbuminuria

Acute thrombosis:
Catheter guided thrombectomy
LMWH, followed by warfarin for 6-12 months.