Block 34 Week 1 Flashcards
functions of the kidney - homeostasis?
- Elimination of metabolic waste
- Water homeostasis
- Electrolyte homeostasis
- Acid base homeostasis
- Blood pressure control
kidney functions - synthesis of?
- activatesVitamin D
- Erythropoietin
- Renin
kidney functions - excretion of?
drugs and drug metabolites
what is serum creatinine affected by?
- influenced by gender ethnicity, age, body mass, diet, exercise
- not sensitive to small changes in function
eGFR?
- Calculated from creatinine, age, gender, ethnicity
- Better reflection of kidney function
- Best measure for use in stable renal function
classification of CKD
CKD =
- eGFR of under 60
- or kidney damage (e.g. abn blood, urine, imaging)
- must be present for more than 3 months
- irreversible and tends to progress
systemic disease causing KD?
- diabetes
- HTN
- atherosclerosis
Immune mediated causes of KD?
- membranous nephropathy
- IgA nephropathy
- SLE
Drugs that can lead to KD?
nsaids
infections that can lead to KD?
- HIV
- HBV
- HCV
- TB
Genetic diseases -> CKD?
- polycystic kidneys
- cystinosis
RF for progression of CKD?
- Untreated underlying disease e.g. SLE, polycystic kidney disease
- modificable
- worse proteinuria
- older age
- smoking
- uncontrolled P
complications of CKD - main cause of death?
- Cardiovascular disease (main cause of death)
other complications of CKD - electrolyte abn?
- Salt/water retention (oedema)
- Electrolyte abnormalities (↕ Na/K)
- Metabolic acidosis
other complications of CKD?
- Hypertension
- Mineral-bone disease (vitamin D, PTH, PO4)
- Anaemia (erythropoietin)
- Uraemia
- Altered drug metabolism
general management of CKD?
- Control blood pressure
- Reduce proteinuria (if present) – ACEi/ARB
- Stop smoking
- Avoid nephrotoxic drugs (eg NSAIDs)
treating complications of CKD - bone related?
- 1α vitamin D
- Phosphate restriction/binding
treatment for complications of CKD - dietary changes?
- Salt restriction
- Bicarbonate supplementation
- EPO replacement
Preparation for CKD 5 (if progressing)?
- Dialysis
- Transplant
- End of life care
AKI stage 1?
Creatinine
- > 26mmol rise
- 50-100% from baseline
- urine output <0.5ml/kg/hr for 6 hrs
stage 2 AKI?
- 100-200% inc in creatinine
- <0.5ml/kg/ hr for 12 hrs
stage 3 AKI?
- > 200% inc in creatinine
- or >354
- or needs dialysis
urine output in stage 3 AKI?
- <0.3ml/kg/hr for 24 hrs
- or anuria for 12 hrs
- or needs dialysis
AKI staging
who is at risk of AKI?
causes of AKI - pre-renal?
- Perfusion failure (“Shock” or blockage of renal artery)
- Made worse by medication eg
- Antihypertensives
- ACEi/ARB, NSAID – interfere with renal autoregulation
ACE, ARB, NSAID can lead to ? AKI
pre-renal
Renal causes of AKI?
Disease affecting the kidney tissue (vasculitis, SLE, multiple myeloma, interstitial nephritis)
Post-renal causes of AKI?
Obstruction of the urinary system (eg stones, tumours, blocked catheters)
Complications of AKI?
- death - mainly sepsis
- HTN
- metabolic acidosis
- salt/water retention - oedema
- anemia - from EPO
general management of AKI?
- Careful fluid balance
- Dietary restriction if needed (eg low potassium)
- Safe prescribing (eg reduce dose of antibiotics)
- Appropriate clinical setting (eg HDU/ITU if needed)
gen management of AKI - dialysis?
Dialysis if needed to control complications (eg pulmonary oedema, hyperkalaemia, acidosis, uraemia)
what is needed for there to be nephrotic syndrome?
- Heavy proteinuria
- Clinical evidence of peripheral oedema
- Hyperlipidaemia
heavy proteinuria in nephrotic syndrome?
- 24 hour urine collection >3-3.5g protein/24 hour or
- Spot urine PCR >300-350 mg/mmol
when does nephrotic syndrome occur?
- when glomerular filtration barrier is damaged leading to inc protein leak
primary diseases causing nephrotic syndrome?
- Focal segmental glomerulosclerosis
- Membranous nephropathy
- Minimal change disease
secondary causes of nephrotic syndrome?
- Diabetes Mellitus
- Cancers
- Drugs
- Infections (eg HIV, HBV, HCV)
- sLE
- Amyloid
Complications of nephrotic syndrome - haematological?
- Thromboembolism
- DVT +- PE
- Renal vein thrombosis
- Arterial (rare)
other complications of Nephrotic S?
- Infection
- Hyperlipidaemia
- Malnutrition
- Acute kidney injury
- Chronic kidney disease
tx of nephrotic syndrome - pharm?
- Diuretics (loop eg furosemide) if massive fluid overload
- Proteinuria reduction – ACEi/ARB
- Thrombo-prophylaxis
- Salt restriction
what is nephritic syndrome?
- proteinuria - <3g protein/ 24 hrs or spot urine PCR <300-350mg/mmol
- haematuria
- oedema
Nephritic syndrome is a ?
medical emergency
what is nephritic syndrome caused by?
- caused by damage to the glomerular endothelium, often inflammation/ immune mediated
what are the autoimmune causes of nephritic syndrome?
- autoimmune diseases - SLE, ANCA vasculitis, Anti-glomerular basement membrane antibody disease
infection related nephritic syndrome?
postinfectious glomerulonephritis, bac endocarditis, HCV
How do patients w CKD present?
- Commonly through routine monitoring of eg hypertension, SLE, drug monitoring
*I ncidental finding (eg routine medical, routine urinalysis, found during investigation for something else) - Family with genetic disease (eg polycystic kidneys)
- Sometimes symptoms (eg pain in polycystic kidney)
- Symptoms caused by lost renal fu nction – only at a late stage (CKD4/5)
how do patients present w AKI?
- Usually in high risk patients in hospital (eg trauma, GI bleed, post surgery)
- Symptoms due to underlying disease (eg SLE, vasculitis)
- Monitoring of known chronic disease (eg prostate disease, chemotherapy)
- Sometimes due to nephritic syndrome (oedema, generally unwell)
- Haematuria (rare)
CKD summary?
- slow - months to years
- eGFR used to measure function
- caused by chronic diseases, genetic diseases, glomerular diseases - diseases that can nephotic syndrome
AKI summary?
- fast - hours to days
- measure serum creatinine or urine output
- caused by acute illness, immune mediated dieasses e.g. nephritic syndrome
- aim is to restore baseline function
urine in nephrotic syndrome?
oedema, frothy urine
what is important in nephritic syndrome?
- immunology tests e.g. ANA, ANCA is important in nephritic syndrome
Most common Ix for renal issues?
US
Proteinuria + haematuria could be
glomerulonephritis
mortality from AKI is?
50%
principle causes of acute renal insuffiency?
common causes of hosp acquired AKI?
the surgical triad -post-op volume depletion, infection and nephrotoxic drugs
at rism groups for AKI?
- elderly
- diabetics
- vasculopaths
- known chronic renal impairment
- sig cardiac dysfunction
- CLD
drugs related to AKI - ACEI?
- ACE-inhibitors and angiotensin II receptorblockers– efferent vasodilatation
drugs related to AKI - NSAIDs?
- NSAIDS– afferent vasodilatation
drugs related to AKI - PPI?
- Proton pump inhibitors– Interstitial nephritis
Other drugs leading to AKI?
- Aminoglycosides
- Contrast medium – 20% risk of AKI
Ix for AKI?
- urine dipstick
- haematology - FBC, coagulation profile, eosinophils, palsma viscosity
- CRP, glucose
- microbiology
- radiology - US, CXR
- immunology - ANA, ANCA, ANTI-GMB
life threatening complications of AKI?
- Hyperkalaemia
- Pulmonary oedema
- Intravascular volume depletion
- Uraemic encephalopathy
- Pericardial fluid
requires dialysis
What is glomerulonephritis?
- inflammation of glomerulus
- 3 cell types of glomerulus: endothelial, epithelial, mesangial cells - produces mesangial matrix
- can be primary or secondary
histology of glomerulonephritis?
- diffuse: all glomeruli affected
- focal: some glomeruli affected
- global: whole glomerulus affected
- segmental: only part of the glomerulus is affected
features of nephrotic S?
- peripheral oedema - pitting oedema
- proteinuria - more than 3.5g/day
- hypoalbuminaemia
what occurs in nephrotic syndrome that increases the thromboembolic risk?
- hypercholesterolaemia
- (inc risk of infection and inc risk of thromboembolic risk)
Nephrotic S - low serum albumin ->
imbalance in starling forces -> fluid in IS space -. secondary hyperaldosteronism -> peripheral oedema
What are the causes of nephrotic syndrome in children?
- minimal change glomerulonephritis - most common cause
- focal segmental glomerulosclerosis - 2nd most common cause
minimal change?
- person has Nephrotic S but light microscopy is normal
- fusion of foot processes on EM
types of minimal change disease?
- Treat w steroids without a biopsy - steroid responsive nephrotic syndrome
- some relapse on steroid withdrawal - relapsing nephrotic syndrome
- steroid dependent NS - requires cont steroid therapy
- steroid resistant nephrotic syndrome
most common cause of nephrotic syndrome in adults?
membranous glomeruloneophritis -
other causes of nephrotic syndrome in adults?
- IgA nephropathy
- diabetic nephropathy
- SLE, amyloidosis
Membranous GN?
- most common finding is thickening of capillary loops - spikes on them are characteristics
How does membranous GN present?
- adults
- presents w proteinuria +/- renal impairment
prognosis of memb GN?
- 1/3 spont recovery, 1/3 persistent proteinuria, 1/3 ESRF
- majority autoimmune
mem GN is associated with?
- adenocarcinoma (lung and GI)
- hep B
- SLE
- drugs - gold. penicillamine - used be used to treat RA
how does IgA nephropathy present?
- commonly presents w visible haematuria 1-2 days following URTI in 75% of younger patients
- can present w nephrotic S, renal failure
IgA nephropathy can be benign but can ?
but 1/3 progress to ESRF/ death over 20 yrs
when is prognosis worse for IgA nephropathy?
- proteinuria
- HTN
- scarring on biopsy
- male
- abn renal function
Alport’s syndrome?
- genetic defect in the gene for alpha-5- chain of type 4 collagen found in the basement membrane
forms of alport’s syndrome?
- X linked
- autosomal recessive
- autosomal dominant
X linked form of alport’s syndrome?
- young males
- haematuria
- proteinuria
- progressive renal failure
what else can be seen with alport’s syndorome?
- haematuria
- proteinuria
- progressive renal failure
- sensorineural deafness
- anterior lenticonus - displacement of the lens of the eye
Female carriers of alports syndrome tend to have?
- non-visible haematuria
How does nephritic syndrome present?
- visible haematuria - smoky urine
- HTN
- AKI
- often oliguria
- some proteinuria
oedema in nephritic syndrome?
- oedema may be present - secondary to oliguria causing salt and water retention, not proteinuria
urine
what is charactistic of nephritic syndrome?
red cell cast in urine
most classical cause of nephritic syndrome in children?
post-streptococcal GN
other causes of nephritic syndrome in children?
- haemulytic uraemic syndrome
- henoch-schonlein purpura
classic causes of nephritic syndrome in adults?
- goodpasture’s
- ANCA-assocuated vasculitis
Other causes of nephritic syndrome in adults?
- SLE
- primary/ secondary mesangiocapillary GN
Post-streptococcal GN?
- presents w diffuse proliferative GN
- Typically 10-14 days after a streptococcal throat infection