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