Renal Medicine 2 Flashcards
Describe the the ways diabetes can affect the kidneys?
Direct glomerular damage: there is basement membrane thickening, leading to increased leakiness of the capillary wall and proteinuria, with eventual glomerular hyalinisation leading to CKD
Ischaemia due to arterial disease: atherosclerosis extends further into the small arteries to cause reduced eGFR and glomerular ischameia
Ascending infection: more common in DM
What is the cause of PKD?
AD or AR inheritance
Describe what PKD is?
ADPKD = more common, both kidneys are gradually replaced by enlarging fluid filled cysts, compressing the parenchyma out of existence
What is the presentation of PKD?
Systemic hypertension, CKD and abdominal swelling due to very large kidneys bilaterally
Balottable kidneys
Renal failure occurs in later life
Cysts in liver, lungs and pancreas but without symptoms
What do cysts in the liver lead to?
Portal hypertension and fibrosis
What is the management of PKD?
As per CKD and screening for berry aneurysms
How does hypertensive renal damage occur?
Long standing renal disease leads to thickening of renal artery walls, making the afferent arterioles inelastic and rigid
Chronic progressively reducing blood flow leads to chronic ischaemia, with progressive loss of glomeruli, replaced by hyaline tissue
This can be exacerbated by renal artery stenosis due to atherosclerosis
What are the two forms of chronic interstitial nephritis?
Reflux associated chronic interstitial nephritis - due to incompetent vesicoureteric valves, predisposing to infection and scarring
Obstructive interstitial nephritis: recurrent episodes of infection occurring due to anatomical abnormality (prostate, retroperitoneal fibrosis, genetic abnormalities or a stone)
What drugs generally require dose reduction due to decreased eGFR?
Gentamicin Cephalosporins Heparin Lithium Opiates Digoxin
What are the three layers of the glomerulus?
Fenestrated capillary epithelium
Basement membrane
Visceral layer: formed by podocytes
What is the purpose of the layered glomerulus?
Together create a sieve that allows small, charged ions through, yet will not allow transport of proteins or blood
What is the primary cause of glomerular disease?
Immunological attack by an antibody or T cell attacking an antigen in the glomerulus, which may be primary (always there) or secondary (acquired/deposited)
What are the secondary factors causing deposition of antigens in glomerular disease
NSAID HSP:
Neoplasm SLE Amyloid Infection Diabetes
HSP
What is the effect of glomerular disease on the capillary layer?
Endothelial cell proliferation: leading to bigger fenestra
Capillary wall necrosis
Glomerulosclerosis: scarring in the mesangium leading to the fenestra and capillaries being pulled apart
What is the effect of glomerular disease on the basement membrane?
Thickened membrane, leading to structural distortion and thus becomes more permeable
What is the effect of glomerular disease on the tubules?
Deposition of cells in Bowman’s space
What do the following terms mean histologically? Global segmental Diffuse Focal
Global: whole glomerulus is decreased
Segmental: small patches of one glomerulus are damaged in a ‘patchy’ fashion
Diffuse: affecting >50% of glomeruli
Focal: affecting <50% of glomeruli
What is the clinical manifestation of glomerulonephritis?
AKI CKD Asymptomatic haematuria Nephrotic syndrome Nephritic syndrome
Rapidly progressive glomerulonephritis (rare - an acute version of nephritic syndrome)
What is nephrotic syndrome?
Triad of:
Proteinuria (at least 3.5g/day)
Hypoalbuminaemia (30g/l)
Oedema (due to decreased oncotic pressure and water retention)
Renal loss of thromboregularatory proteins or liporegulatory proteins may lead to hyperlipidaemia or venous thrombosis
Where does oedema from nephrotic syndrome tend to occur?
Periorbitally and peripherally in limbs
What are the most common primary causes of nephrotic syndrome?
Minimal change nephropathy
Membranous glomerulonephritis
Proliferative glomerulonephritis