Renal vascular disease
Malignant hypertension
- Characterised by severe increase in BP, grade III or IV hypertensive retinopathy and renal failure
Pre-eclampsia
- Increased BP plus proteinuria and oedema in the 2nd3rd trimester
- The proteinuria is due to glomerular endothelial cell swelling
- It may result in ARF
Renal diseases causing hypertension are the commonest cause of secondary hypertension
- Most renal diseases are associated with a rise in BP
- Most common are;
- DM
- GN
- Chronic interstitial nephritis
- Polycystic kidneys
- Renovascular disease
Renovascular disease
- Stenosis of the renal artery or one of its braches
- Causes;
- Atherosclerosis
- Fibromuscular dysplasia
- Rarer causes;
- Takayasu’s arteritis
- Antiphospholipid syndrome
- Post-renal transplant
- Thromboembolism
- External mass compression
- Clinically there is increased BP that is resistant to therapy, worsening renal function after ACEI or ARB, sudden onset pulmonary oedema
- Tests
- Ultrasound
- CT/MRI
- Renal angiography is the gold standard
- Treat with percutaneous renal angioplasty +/- stent or revasularisation surgery
Haemolytic uraemic syndrome
- Characterised by microangiopathic haemolytic anaemia, intravascular haemolysis and red cell fragmentation
- Endothelial damage triggers thrombosis, platelet consumption and fibre strand deposition mainly in the renal microvasculature
- The strands cause mechanical damage of passing red cells
- Thrombocytopenia and ARF result
- Most commonly caused by E.coli 0157 which produces a verotoxin which damages endothelial cells
- Tests
- Blood film -fragmented RBC (shistocytes)
- Reduced platelets and Hb
- Clotting tests are normal
- There may be haematuria or proteinuria
- Often resolves spontaneously
- Dialysis for AFR may be required
- Plasma exchange with cryoprecipated depleted FFP may be required
Thrombotic thrombocytopenic purpura
- Associated with;
- Fever
- Fluctuating CNS signs - fits, hemiparesis, reduced consciousness, reduced vision
- Microangiopathic haemolytic anaemia (severe often with jaundice)
- Thrombocytopenia (severe, often with mucosal bleeding)
- Renal failure
- Adult females are generally affected - associated with a high mortality
- There is a genetic or acquired deficiency in the protease that cleaves multimers of von Willebrand factor (vWF) resulting in large multimers which cause platelet aggregation and fibrin deposition in small vessels leading to microthrombi
- It is a haematological emergency so get expert help
- Urgent plasma exchange may be life saving
- Give steroids
Cholesterol emboli
- May be released from atheromatous plaques which lodge in the distal circulation o cause ischaemia
- An inflammatory response leads to fever, myalgia and raised eosinophils
- Risks;
- Atheroma
- Rasied cholesterol
- Aortic aneurysm
- Thrombolysis
- Arterial catherisation
- Signs;
- Livedo reticularis, gangrene, GI bleeds, renal failure