Renal vascular disease Flashcards by Clara Sage

What is renovascular disease defined as?

Stenosis of the renal artery or one of its branches

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Causes of renal artery stenosis

Normally atherosclerosis - older patients - can progress and cause complete occlusion
Fibromuscular dysplasia in younger patients - doesn’t usually cause occlusion

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Why hypertension in renal artery stenosis

Because decreased renal perfusion stimulates JG apparatus to release renin - vasoconstriction and salt and water retention

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Renal impairment in renal artery stenosis

Angiotensin II constricts efferents more than afferents therefore maintains glomerular filtration rate - if give ARB or ACEi - decreasing renal function

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Oedema in renal artery disease

Angiotensin II causes increased glomerular pore size therefore mild proteinuria can occur

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Rarer causes of renal artery stenosis

Takayasu’s inflammatory artertitis, neurofibromatosis, pressure from renal artery aneurysms and extrinsic pressure

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What biochem finding in renal artery stenosis

Hypokalaemia - aldosterone promotes K+ secretion

Therefore hypokalaemia unless there is renal impairment

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DX of renal artery stenosis

MR angiography and USS

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Rx of renal artery stenosis

Transluminal angioplasty
Stenting
Revascularisation surgery

HTN treatment - ARB or ACEi need careful monitoring

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What is haemolytic uraemic syndrome?

Microangiopathic haemolytic anaemia
Endothelial damage in microvasculature - usually caused by E.Coli (in outbreaks in children after eating uncooked meat)
Endothelial damage triggers thrombosis, platelet consumption and fibrin deposition

Causes mechanical destruction of RBCs

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What does HUS cause?

Thrombcytopenia and AKI

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Signs of HUS

Abdominal pain, bloody diarrhoea and AKI

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Rx of HUS

Dialysis may be needed for AKI

Plasma exchange for severe cases

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Other features present in Thrombotic Thrombocytopenia

CNS signs (seizures, hemiparesis, decreased consciousness and fever)

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Management of kidneys in diabetes

Screening for microalbuminuria - as soon as detected started on ACE i (or ARB) even if not HTN

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What is renal tubular acidosis?

Metabolic acidosis due to impaired acid secretion by the kidney
Hypercholeraemic acidosis and normal anion gap

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Types of RTA

4 types 
1 - distal 
2- proximal 
3 - rare combination of 1 + 2 
4 - hyperkalaemic

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What causes type 1 RTA

Failure to excrete H+ in distal tubule - even when metabolic acidosis
- Inherited disorders but also acquired with SLE, and drug related

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Features of type 1 RTA

Rickets, osteomalacia - because buffer H+ with calcium in bone

Nephrocalcinosis with renal calculi - recurrent UTIs (due to hypercalciuria, decreased urinary citrate (reabsorbed as buffer for H+) and alkaline urine - all favour calcium phosphate stone formation

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Treatment of type 1 RTA

Oral sodium bicarbonate or citrate

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What causes type 2 RTA

Bicarbonate leak from proximal tubule

Normally associated with more general tubular defect - Fanconi’s

What biochem in type 2 RTA

Hypokalaemia because of osmotic diuretic effect of decreased bicarb reabsorption causing increased flow rate and increased K+ excretion

DX of type 2 RTA

Sodium bicarb load and there is high fractional excretion of bicarb

RX of type 2 RTA

High dose bicarb - patients find it intolerable

What causes type 4 RTA?

Hyporeninaemic hypoaldosteronism Addisons Diabetic nephropathy Interstitial nephritis Hypoaldosteronism causes hyperkalaemia and acidosis

Rx of type 4 RTA

treat underlying cause | furosemide to hyperkalaemia

What is Fanconi syndrome?

Proximal tubular dysfunction leading to loss of amino acids, phosphate, bicarb and glucose

What does Fanconi syndrome cause

Dehydration Osteomalacia Metabolic acidosis Electrolyte abnormalities

Congenital causes of Fanconi syndrome

Congenital - idiopathic, cystinosis, Wilsons, tyrosinemia, Lowe syndrome

Acquired causes of Fanconi syndrome

heavy metal poisoning drugs (gent, cisplatin, ifosfamide) light chains (myeloma, amyloid)

Rx of Fanconi syndrome

Treat cause replace K+, bicarb, phosphate Vit D supplements

What is cystinosis and features

Congenital accumulation of cystine Causes Fanconi syndrome, visual impairment, myopathy, hypothyroidism Progression to ESRF

Rx of Cystinosis

Can give oral cysteamine - poorly tolerated | Renal transplant - fanconis does not reoccur but extra-renal disease progresses

What is Bartter's syndrome?

Inherited mutation in the co-transporter targeted by LOOP diuretics Therefore alkalosis, hypokalaemia and hypercalciuria Usually presents in infancy - polyuria, polydipsia, tendency to dehydration

Rx of Bartters syndrome?

Replace K+, consider DOMETHACIN - prostaglandin synthesis inhibitor - resolves abnormalities

What is Gitelman syndrome?

Inherited mutation in co-transporter targeted by thiazide diuretics therefore Low K+, metabolic alkalosis, hypocalciuria and low mg2+

Presentation and Rx of Gitelman syndrome?

Usually present later than Bartters- with muscle cramps, weakness and low BP Replace Mg2+ K+ supplementation

Prevalence of autosomal dominant polycystic kidney disease (APKD)

1 in 1000

2 types of autosomal dominant polycystic kidney disease

PKD1 mutation - 85% - reach ESRF by 50s | PKD2 mutation - 15% - reach ESRF by 70s

Renal signs of PCKD

``` Renal enlargement with cysts Abdominal pain (stretching of capsule) Haematuria - haemorrhage into a cyst (pain also) Cyst infection Renal calculi HTN Progressive renal failure ```

Extrarenal signs of PCKD

``` Liver cysts Intra-cranial berry aneurysms - SAH Mitral valve prolapse Ovarian cysts Diverticular disease ```

Treatment of PCKD

``` Low target BP Treat infections Dialysis or transplantation Genetic counselling High water intake and decrease salt intake Can do cyst removal or nephrectomy ```

Screening for SAH in PCKD

Magnetic resonance angiography Done in 1st degree relatives of those with SAH + ADPKD Or if certain occupations - pilot

Prevalence of autosomal recessive PCKD, presentation and treatment

1 in 40,000 Present in infancy with multiple renal cysts and congenital hepatic fibrosis No current therapy

What is medullary cystic disease

Inherited disorder with tubular loss and medullary cyst formation Juvenile (recessive) form accounts for 10-20% of all ESRF in children Adult form (dominant) is rare

Signs of medullary cystic disease

Shrunken kidneys, cysts only in medulla | Salt wasting, polyuria and polydipsia, enuresis (can't concentrate urine) failure to thrive and renal impairment

Extrarenal signs of medullary cystic disease

``` Retinal degeneration Retinitis pigmentosa Skeletal changes Cerebellar ataxia Liver fibrosis ```

What is Von-Hippel Lindau syndrome?

Chief cause of inherited renal cancers - mutations in VHL tumour-suppressor gene

What is Alport syndrome?

Mutation in gene coding type 4 collagen - GBM splitting - collagen targeted in GP therefore risk of Goodpastures post-renal transplant

Signs of Alport

Haematuria, proteinuria and progressive renal insufficiency | Often systemic manifestations too