Lecture 15: Renal disease Flashcards
(34 cards)
What can happen to glomerular function?
Can become leaky or blocked
Problems with glomeruli = Blood or protein in urine
What happens to a blocked glomeruli?
AKI or CKD
- Increased creatinine
- Low GFR
Describe normal renal-protein handling:
- Kidneys handle <150mg/24h urinary protein
Barriers to urinary protein
- Glomeruli
- Tubules - reabsorb and degrades most of filtered protein
What is Haematuria? and what can it be from? and whats important to remember?
- Blood in urine
Can be from: glomerular disease, tumour, infection
Important to consider there is a spectrum of degrees of blood in the urine
What happens with a leaky filter?
- Leaking of blood or protein through glomerulus
- Kidney function may be normal
What is the main type of protein in the urine?
Albumin
Other types of proteins in small amounts
How is protein in the urine measured?
- 24hr urine
- Albumin:Creatinine
- Protein:Creatinine
What is microalbuminuria?
- 30-300mg albumin/24hrs normally
Albumin:Creatinine ratio
- 2.5mg/nmol (normal)
- 2.5-25 mg/nmol (MICROALBUMINURIA)
- >25mg/nmol (PROTEINURIA)
What are the causes of microalbuminuria?
- Diabetes mellitus
- Fever
- Exercise
- HF
- Poor glyceamic control
What is nephrotic syndrome?
- > 3.5g/day urinary protein
- Low serum albumin
- Oedema
Frothy urine, Hypercholesterolaemia, Blood clots
Renal function normally impaired.
What are the mechanisms for oedema?
- Increased albumin excretion
- Liver cant keep up producing albumin
- Reduction in oncotic pressure (protein in blood)
- Egression of fluid into interstitial space
What is starling equation?
Starlings equation:
Flux = Cap. permeability (intravascular hydrostatic P - interstitial hydrostatic P)
Cap hydrostatic P: Pushes fluid out of vessel if high
Cap oncotic P: Pulls fluid into vessel if high (derived from plasma proteins)
What happens to starlings forces in nephrotic syndrome?
Nephrotic syndrome = low albumin
- Low oncotic P and high hydrostatic P
- Water pushed from intravascular compartment into tissue
How does nephrotic syndrome altered blood lipid profile?
Low plasma oncotic P -> Increased lipoprotein produced by liver -> Increased cholesterol production.
Meanwhile:
Reduced metabolism VLDL-LDL -> Increased triglycerides
What are some possible consequences of nephrotic syndrome?
Thromboembolism risk increases
Malnutrition risk increases
Risk of infection increases
- Reduction of AB production
- Decreased complement pathway
i.e
- Increased bacterial infections
- Increased chickenpox in children
What happens to renal function in nephrotic syndrome?
Can be normal, can be AKI or CKD.
SPECTRUM
What else can cause leaking glomeruli?
- Majority due to glomeruli disease
- Other major cause is diabetes (mainly protein in urine)
Describe the timecourse of GFR in a person with diabetic nephropathy:
GFR increases to a hyperfiltration state before it declines over time and continues to
Meanwhile a microalbuminuria develops and then an over proteinuria
CONTROLLING BLOOD PRESSURE CAN LIMIT DECREASE IN GFR AND PROTEINURIA
What happens in acute tubular necrosis?
Tubular epithelium are damaged and then become necrotic because of ischeamic injury. These cells slough away and block the tubule, decreasing GFR
What are the signs and symptoms of acute glomerulonephritis?
Leaky glomeruli: Blood +/- protein
Nephrotic syndrome:
- Unwell
- oliguric
- hypertensive
- volume overload
- Signs of other multi-system disease i.e heamoptysis, rash, arthritis, fever
- MSU - Blood/proteins i.e red cell casts
What are red cell casts in glomerulonephritis?
Damaged RBC b/c passed the glomerulus
Whats nephrotic syndrome versus nephritic syndrome:
Nephritic syndrome:
- Inflammation
- Blood in urine
- RBC casts
- AKI
Nephrotic syndrome
- Oedema
- Proteinuria
- Variable renal function
Whats the diagnosis of proteinuria?
- May be associated with AKI or CKD but may have normal kidney function
- Need to find cause of proteinuria i.e is it diabetes or glomerulonephritis
- Generally need kidney biopsy
What is the treatment of proteinuria?
Key treatment is management of blood pressure!!
