Renal diseases 1 Flashcards
What are the 4 main functions of the kidney?
1) Eliminating metabolic waste products
2) Regulating fluid and electrolyte balance
3) Influencing acid-base balance
4) Production of hormones - renin, eryhtropoietin (stimulates red cell production)
What are the 6 main presentations of renal disease?
1) Acute renal failure
2) Nephrotic syndrome
3) Acute nephritis (nephritic syndrome)
4) Chronic renal failure
5) Haematuria
6) Proteinuria
Does the clinical presentation necessarily indicate the cause of renal disease?
No - each clinical presentation has a variety of causes
What are the clinical features of acute renal failure? 2
1) Rapid rise in creatinine and urea
2) Generally unwell
What 3 things make up nephrotic syndrome?
1) Oedema
2) Proteinuria
3) Hypoalbuminaemia
What is important about the proteinuria in nephrotic syndrome?
Must be greater than 3g per 24 hours
Mostly albumin
What are the 4 things that make up nephritic syndrome/acute nephritis?
1) Oedema
2) Proteinuria
3) Haematuria
4) Renal failure
How does chronic renal failure present?
Slowly declining renal function
What 5 disciplines are needed for diagnosis of renal disease?
1) Renal physician - clinical history and examination
2) Biochemists - blood tests and urinalysis
3) Pathologist - always light microscopy of renal biopsy, sometimes, electron microscopy and fluoroscopy in specific cases
4) Urologist
5) Radiologist- obstruction, kidney size, structural abnormalities
When may a urologist be needed in diagnosis of renal disease?
Cytoscopy may be needed in cases of obstruction and some cases of haematuria (could be a sign of malignancy)
What blood tests and urinalysis is performed in diagnosing renal disease?
Bloods - urea, creatinine
Urine - protein, electrolytes
What are the 3 things forming the filtration barrier in the kidneys?
1) Podocyte foot processes
2) Endothelial cells
3) Basement membrane
NB. damages to any of these can impair filtration and thus renal function
What is the course of blood/ filtrate through the nephron?
1) Branches of renal artery
2) Afferent arteriole
3) Filtrate filtered out into bowman’s capsule
4) Filtrate through proximal convuluted tubule
5) Through descending limb of henle, loop of henle and ascending limb of henle
6) Through distal convuluted tubule
7) All excreted filtrate through the collecting duct leading to the pelvis of the kidney
Why can damage of the glomerulus lead to damage to the tubule?
Blood flowing through the glomerulus and the efferent arteriole is the blood supplying the tubules so any damage to glomerulus could alter the blood supply to the tubules which can become ischaemic and thus damaged
What are the 2 classes of mechanisms which can damage the glomerulus?
1) Immunological
2) Non immunological
Name 3 immunological mechanisms of damage to the glomerulus, which part specifically is damaged?
1) Circulating immune complexes deposited in the glomerulus
2) Circulating Ag deposit in the glomerulus
3) Ab to basement membrane or other components of the glomerulus produced
All of these lead to damage to the basement membrane through complement an neutrophil activation, production of reactive oxygen species and presence of clotting factors in glomerulus
Name a non immunological mechanism of damage to th glomerulus, which in particular damages the blood vessels of the glomerulus?
Injury to the endothelium of the vessels
Name 3 non immunological mechanisms of damage to the glomerulus which in particular damage the basement membrane?
1) Altered basement membrane due to hyperglycaemia in diabetes (abnormal sugars and glyocosylated proteins in blood)
2) Abnormal basement membrane or podocytes due to inherited disease
3) Deposition of abnormal proteins in the kidney eg. amyloid
What are the 2 classes of mechanisms damage to the tubules of the nephron?
1) Ischaemic
2) Toxic
What are the 3 ischaemic mechanisms of damage to the tubules of the nephron?
1) Hypotension
2) Damage to vessels within the kidney
3) Glomerular damage
All lead to reduced blood supply to the tubules and thus tubular damage
What is important about renal function in tubular damage?
The degree of tubular damage correlates well with renal function (this isnt however always the case with glomerular damage)
What are the 4 toxic mechanisms of damage to the tubules of the nephron?
1) Direct toxins
2) Hypersensitivity reactions eg. to drugs
3) Deposition of crystals in tubules (most common is gout)
4) Deposition of abnormal proteins in the tubules
Give the 5 mechanisms of vascular damage to the kidneys (blood supply to both glomerulus and tubules)?
1) Hypertension
2) Diabetes
3) Atheroma eg. renal artery stenosis
4) Thrombotic microangiopathy
5) Vasculitis
Give a common cause of thrombotic microangiopathy?
Haemolytic uraemic syndrome
What is thrombotic microangiopathy?
Thrombi in the capillaries and small arterioles due to damage to the endothelium
Causes of that endothelial damage include bacterial toxins (ie this can a complication of bacterial infection), some drugs and abnormalities in complement or clotting systems
What is vasculitis?
- Acute or chronic inflammation of blood vessel walls
- Can get obliteration of lumen by inflammation
- Various different types affecting different sizes of vessel
- Can affect adults and children
Give one common type of vasculitis?
Wegener’s granulomatosis
Which 3 glomerular ‘diseases’ can be both descriptions of the microscopic appearance due to a known cause and also disease names when the cause is unknown ie. idiopathic diseases?
All can be secondary to known cause or idiopathic diseases:
1) Membranous nephropathy
2) Focal segmental glomeruloscelrosis (FSGS)
3) Mesangiocapillary glomerulonephritis
Are: 1) proliferative glomerulonephritis 2) Crescentic glomerulonephritis 3) Thrombotic microangiopathy appearances or diseases of the glomeruli?
Appearances secondary to known causes
Name 6 glomerular diseases (which don’t describe glomerular appearances but just diseases)?
1) Minimal change disease
2) Post infective glomerulonephritis
3) Anti-GBM disease
4) IgA nephropathy
5) Henoch-Schonlein purpura
6) Lupus nephritis (SLE)
What is always the cause of nephrotic syndrome?
Always due to damage to the glomerulus
Other than the 3 defining features of nephrotic syndrome, what 2 other clinical features can be present?
1) Hypertension
2) Hyperlipidaemia
What are the 2 main complications of nephrotic syndrome?
1) Infection
2) Thrombosis
What is the most common cause of nephrotic syndrome in adults seen on renal biopsy?
Idiopathic membranous nephropathy
Which age group and gender is idiopathic membranous nephropathy most common in?
More common in males than females
Common in adults 30-60
What percentage of people with idiopathic membranous nephropathy progress to end stage renal failure?
20-30%
What are the second and third most common causes of nephrotic syndrome in adults seen on renal biopsy?
2nd = focal segmental glomerulosclerosis 3rd = minimal change disease