Week 9 Renal system 1 Flashcards
What is the functions of the kidney?
Eliminating metabolic waste products
Regulating fluid and electrolyte balance
Influencing acid-base balance
Production of some hormones
What hormones are produced by the kidney?
Renin: fluid balance
Erythropoietin: stimulates red cell production
What are the different presentations of renal disease?
Acute renal failure
Nephrotic syndrome
Acute nephritis (nephritic syndrome)
Chronic renal failure
Haematuria
Proteinuria
What are the 5 ways of diagnosing a patient?
Renal physician Radiologist Biochemist Urologist Pathologist
Where are the glomerulus in the kidney found?
Glomerulus are coiled capillary that are found in the bowmans space
What structures in the kidney allow filteration of the blood?
Podocyte foot processes, endothelial cells and basement membrane allow filtration
What are the immunological mechanisms of glomerular damage?
Circulating immune complexes deposit in glomerulus
Circulating antigens deposit in glomerulus
AutoAntibodies to basement membrane or other components of glomerulus
What is the consequence of immunoligical mechanisms that cause glomerular damage.
Lead to Complement activation
Neutrophil activation
Reactive oxygen species
Clotting factors
What are the non-immunological mechanisms of damaging glomerur?
Injury to endothelium of vessels e.g. hypertension
Altered basement membrane due to hyperglycaemia in diabetes
Abnormal basement membrane or podocytes due to inherited disease
Deposition of abnormal proteins in the kidney e.g. amyloid
What are the ischaemic mechanisms for causing tubular damage?
Hypotension –> septic shock can cause this
Damage to vessels within kidney
Glomerular damage
Why does glomerular damage cause damage to the tubular?
If anything damage the glomerular will damage the tubule because disruption to blood supply in the glomerular will reduce blood supply to the tubule and get necrosis and death
What are the toxic mechanisms of tubular damage?
Direct toxins
Hypersensitivity reactions e.g. to drugs
Deposition of crystals in tubules
Deposition of abnormal proteins in the tubules
What does damage to renal tubules correlate with?
The degree of damage to renal tubules correlates well with renal function
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What are the mechanisms of vascular damage of the kidney?
Thrombotic microangiopathy
Vasculitis
Hypertension
Diabetes
Atheroma e.g. Renal artery stenosis
How does vasculitis cause vascular damage to the kidney?
Most common cause
Acute or chronic inflammation of blood vessel walls
obliteration of lumen by inflammation
various different types affecting different sizes of vessel
adults and children can be affected
e.g. Wegener’s granulomato
What is the thrombotic microangiopathy mechanism for vascular damage?
Not very common
Thrombi in capillaries and small arterioles
Due to damage endothelium
Causes of endothelial damage include bacterial toxins, some drugs, abnormalities in complement or clotting systems
e.g. Haemolytic uraemic syndrome
How do you name glomerular disease?
Glomerular disease name can be based on the actual disease that has a idiopathic cause sometimes
Or can be based on the appearance (when secondary to a known cause)
What is the cause of nephrotic syndrome?
Always due to damage to glomerulus
What is the consequence of nephrotic syndrome?
Oedema --> can be chronic Proteinuria (>3g in 24h) Hypoalbuminaemia \+/- hypertension \+/- hyperlipidaemia
What are the complications of nephrotic syndrome?
Infection
Thrombosis
What are the common causes of nephrotic syndrome in adults seen on renal biopsy?
Membranous nephropathy (most common)
Focal segmental glomerulosclerosis (FSGS)
Minimal change disease
Other causes: diabetes, lupus nephritis, amyloid
What is the profile of membranous nephropathy?
Idiopathic
Primary glomerular disorder of unknown cause
Usually adults 30-60, M>F
20-30% progress to end stage renal failure
What is focal segmental glomerulosclerosis?
A pattern of kidney damage with various possible causes (idiopathic, genetic, heroin use, HIV. Most are idiopathic)
M>F
In minimal change disease is the biopsy abnormal and in which gender is it more common in?
Biopsy is normal on light microscopy
M=F
What is the common cause of nephrotic syndrome in children seen on renal biopsy?
Minimal change disease (most common)
No abnormality seen on light microscopy
Majority of children have excellent prognosis
Focal segmental glomerulosclerosis (FSGS)
rare
Other causes are rare
What are the presentations of acute nephritis?
Oedema Haematuria Proteinuria Hypertension Acute renal failure
What are the common causes of acute nephritis?
Post-infective glomerulonephritis IgA nephropathy Vasculitis Lupus Other forms of primary glomerulonephritis
How does post infective glomerulonephritis occur?
Typically occurs a few weeks after Streptococcal throat infection
The antibodies against strept cross react with the kidney and cause renal failure
Most recover completely
How common is IgA nephropathy?
Most common primary glomerular disease worldwide
Teenagers and young adults with haematuria
20-50% progress to renal failure over 20 years
How does vasculitis cause acute nephritis and what is its presentation?
Inflammation to the blood vessel that damage the glomerulus
Presentation–> Fever, generally unwell, may have rash, myalgia, arthralgia
In who do you see lupus causing acute nephritis?
Young women
What are the common cause of acute nephritis in children?
Post-infective glomerulonephritis
IgA nephropathy
Henoch-Schonlein purpura
What is Henoch-Schonlein purpura?
Specific type of IgA nephropathy, M>F
Typically young boys/teenagers with arthralgia, abdo pain, rash, haematuria, acute renal failure
Most recover completely
What is haemolytic uraemic syndrome?
Typically children with E. Coli 0157 enteritis
Acute nephritis + haemolysis + thrombocytopaenia
What is the diagnosis and prognosis of acute renal failure?
Diagnosis – anuria/oliguria + raised creatinine and urea
Many patients will recover and have good renal function if they had healthy kidneys previously
Short term dialysis may be needed in some patients
What are the caues of acute renal failure?
Pre-renal: reduced blood flow to kidney
Severe dehydration
Hypotension e.g. Bleeding, septic shock, left ventricular failure
Post-renal: obstructed urinary tract Tumours of urinary tract Tumours in pelvis Bladder stones Prostatic enlargement
Renal: damage to kidney
When is biopsy helpful to identify acute renal failure?
When the cause is damage to the kidney
Not useful in pre or post renal causes
What do all biopsies show in acute renal failure?
All biopsies will show “ATN” – acute tubular necrosis/ injury/damage/acute kidney injury (ATI/ATD/AKI)
What is the main cause of acute renal failure in adults?
Vasculitis –> rash fever, muscle pain
Acute interstitial nephritis/tubulointerstitial nephritis (tubular damage with inflammation, most commonly caused by drug reactions)
What is the common cause of renal failure in children?
Henoch-Schonlein purpura
Haemolytic uraemic syndrome
Acute interstitial nephritis
What is the most common cause of acute renal failure?
Pre renal –> reduced blood flow to kidney
What are the complications of acute renal failure?
Cardiac failure (fluid overload)
Arrythmias (electrolyte imbalance –> imbalanced potassium levels)
GI bleeding
Jaundice (hepatic venous congestion)
Infection, especially lung and urinary tract
What is the treatment of acute renal failure?
Short term dialysis may be needed
Treat the underlying cause
Define chronic renal failure?
Permanently reduced GFR – reduced number of nephrons
What are the 5 stages of chronic renal failure?
Stage 1: Kidney damage with normal or increased GFR (>90 mL/min/1.73 m2)
Stage 2: Mild reduction in GFR (60-89 mL/min/1.73 m2)
Stage 3: Moderate reduction in GFR (30-59 mL/min/1.73 m2)
Stage 4: Severe reduction in GFR (15-29 mL/min/1.73 m2)
Stage 5: Kidney failure (GFR
What is the common cause of chronic renal failure in adults?
Diabetes (commonest)
Glomerulonephritis
Reflux nephropathy
What is reflux nephropathy?
Chronic reflux of urine up the ureter leading to repeated infections and scarring of the kidney
Commonly for younger patients
At what stage of chronic renal failure do you need treatment?
Stage 4 and 5
If you are on dialysis what stage are you at?
Automatically stage 5
What are the common causes of chronic renal failure in children?
Developmental abnormalities/malformations
Reflux nephropathy
Glomerulonephritis
Why is renal biopsy not helpful in establishing chronic renal failure?
Kidney shows severe scarring with loss of glomeruli and tubules
Similar changes are seen in end-stage renal disease due to any cause
What are the effects of chronic renal failure? (4)
Reduced excretion of water and electrolytes: oedema, hypertension
Reduced excretion of toxic metabolites
Reduced production of erythropoietin: anaemia
Renal bone disease
What is the common cause if a elderly patient has acute renal failure?
Acute interstitial nephritis due to drug reactions
Myeloma –> tumor of plasma cells which will release large amount of immunoglobins that accumulate in the glomeruls and tubules that cause damage to the kidneys
What is the diagnosis if a young male has haematuria and rash?
Henoch-Schonlein purpura
What is the possible diagnosis if a teenager/young adult has haematuria?
Post-infective glomerulonephritis
IgA nephropathy
What is the likely cause if a adult has renal failure, fever and mylgia?
Vasculitis?
What is the diagnosis if a young women has haematuria and facial rash?
Lupus
What is the diagnosis if a adult has nephrotic syndrome?
Membranous nephropathy
Mostly idiopathic
What is the likely diagnosis if a child has nephrotic syndrome?
Minimal change disease
What investigations are needed to identify the cause of isolated haematuria?
Cystoscopy and other urological investigations are likely to be needed
What are the likely renal cause of Haematuria +/- proteinuria with normal renal function?
IgA nephropathy
Thin basement membrane disease
Alport type hereditary nephropathy
What is thin basement membrane disease?
Inherited condition causing abnormally thin basement membranes in the glomerulus
If no other renal disease present, kidney function will remain normal
What is Alport type hereditary nephropathy?
Inherited abnormalities of collagen type IV cause abnormal basement membrane in the glomerulus, sometimes with eye and ear problems
Renal failure +/- deafness +/- ocular problems
May be autosomal or X-linked
What is isolated proteinuria?
Proteinuria less than the nephrotic range, without haematuria, renal failure or oedema
What are the causes of isolated proteinuria in adults?
FSGS
Diabetes
Lupus
What is the common cause of isolated proteinuria in children?
Henoch-Schonlein purpura
FSGS
What is a complication of acute pyelonephritis ?
Abscess formation
What is Pyelonephritis ?
Infection of the kidney
What is the action of acute pyelonephritis?
Instrumentation of urinary tract
Structural abnormalities of urinary tract
In who is acute pyelnophritis common in?
Diabetics
More common in women (ascending infection)
What are the two routes of pyelonephritis?
Infection can occur via haematogenous spread
Infection via ascending route from bladder
What is chronic pyelonephritis associated with?
most associated with obstruction of urinary tract and reflux of urine up ureter
What can chronic pyelonephritis lead to?
Leads to scarring of the kidney and can lead to renal failure
What are the complications of chronic pyelonephritis?
Scarring of kidney
-Chronic renal failure
What is the cause of renal artery stenosis?
Due to atheroma (most common) or arterial dysplasia
What does renal artery stenosis lead to?
Leads to ischaemia of the affected kidney
Activation of renin-angiotensin-aldosterone system leads to hypertension
Loss of renal tissue due to ischaemia leads to reduced renal function
How does vasculitis affect the kidney?
Vasculitis is inflammation of blood vessels
Various types occur and affect different sizes of vessels
Inflammation can affect the glomerular vessels and lead to clotting with obliteration of capillary lumens and destruction of the glomerulus
Inflammation of larger arterioles within the kidney can lead to hypoxia of the tubules
Often affects other vessels around the body causing rash, muscle and joint pains
Patients can also have fever and weight loss due to the inflammation
How does hypertesion affect the kidney?
Hypertension damages renal vessels leading to thickening of the vessel wall and reduction in size of the lumen
This produces chronic hypoxia which leads to loss of renal tubules and reduced renal function
Reduced blood flow in the kidney leads to activation of the renin-angiotensin-aldosterone system which exacerbates hypertension
How does diabetes affect the kidney?
Diabetes is the commonest cause of end-stage renal failure in Europe and the USA
Hyperglycaemia is the main cause of diabetic nephropathy by damaging the basement membrane
Basement membrane becomes thicker and the glomerulus produces excess extracellular matrix which forms nodules
How does myeloma affect the kidney?
Tumour of plasma cells producing immunoglobulins
Excess immunoglobulins deposit in kidney tubules
Tubules become damaged
Inflammation and fibrosis of kidney occurs
Loss of renal tubules leads to declining kidney function
Renal impairment due to myeloma is usually irreversible
