Renal Flashcards
what is an acute kidney injury (AKI)? how is it measured?
- an acute drop in kidney function
- serum creatinine
NICE criteria to diagnose an AKI?
- rise in creatinine of 20 micromol/L or more in 2 days (48 hours)
- rise in creatinine of 50% or more in 7 days
- urine output of less than 0.5ml/kg/h for over 6 hours
what is normal urine output?
0.5ml per kg per hour
risk factors for developing an AKI?
- chronic disease: CKD, HF, DM, liver disease
- old age (>65)
- cognitive impairment
- drugs (NSAIDs, ACE-i)
- contrast used in CT scans
how can the causes of AKI be classified? which is most common?
- pre-renal (most common)
- renal
- post-renal
examples of pre-renal causes of AKI?
- dehydration
- hypotension (shock)
- HF
describe the pathophysiology of pre-renal AKI
- pathology causing reduced blood flow to the kidneys
- less blood gets filtered through them
describe the pathophysiology of renal AKI
- intrinsic disease of the kidney
- makes it less able to filter blood
examples of renal causes of AKI?
- glomerulonephritis
- interstitial nephritis
- acute tubular necrosis
describe the pathophysiology of post-renal AKI
an obstruction to outflow causes urine to build up in the kidney and reduce kidney function
examples of post-renal causes of AKI?
- kidney stones
- Ca of abdomen / pelvis
- ureter / urethral strictures
- enlarged prostate (BPE)
- Ca of prostate
investigations in AKI?
- urinalysis
- USS of urinary tract (?obstruction)
what might urinalysis show in AKI?
depends on underlying cause:
- leukocytes and nitrites (infection)
- protein and blood (acute tubular necrosis, infection)
- glucose (diabetes)
how can AKI be prevented?
- avoid nephrotoxic meds where possible
- ensure adequate fluids are given
management of AKI?
treat underlying cause:
- fluid rehydration (IV)
- stop NSAIDs / antihypertensives
- relieve obstruction (e.g. catheter to get past an enlarged prostate)
if severe without clear cause, refer to renal
complications of AKI?
- hyperkalaemia
- fluid overload, HF, pulmonary oedema
- metabolic acidosis
- uraemia
which 2 complications could uraemia (secondary to AKI) cause?
- pericarditis
- encephalopathy
what is CKD?
permanent and progressive reduction in kidney function
causes / risk factors of CKD?
- DM
- HTN
- age-related decline
- glomerulonephritis
- polycystic kidney disease
- drugs
drug causes of CKD?
- NSAIDs
- PPIs
- lithium
presentation of CKD?
- may be asymptomatic
- pruritus
- reduced appetite, nausea
- oedema
- muscle cramps
- peripheral neuropathy
- pallor
- HTN
investigations for CKD?
- eGFR
- urine albumin : creatinine ratio (ACR)
- urine dipstick
- renal USS
how must eGFR be done in order to diagnose CKD?
2 tests done 3m apart
what is a significant urine ACR reading in CKD? what does this mean?
- 3mg/mmol or more
- indicates proteinuria
what might urine dipstick show in CKD? why is this important?
- haematuria
- could be bladder Ca, investigate!!!!
which CKD patients should be offered renal USS?
- accelerated disease
- haematuria
- FHx of polycystic kidney disease
- evidence of obstruction
how is CKD staged?
G score for each eGFR:
- G1 = >90
- G2 = 60-89
- G3a = 45-59
- G3b = 30-44
- G4 = 15-29
- G5 = <15 (end-stage renal failure)
what is A score in CKD?
score based on the albumin : creatinine ratio
how is CKD diagnosed?
at LEAST eGFR <60, OR proteinuria
complications of CKD?
- anaemia
- bone disease
- CVD
- peripheral neuropathy
- dialysis-related problems
when does a CKD patient need a renal referral?
- eGFR <30
- ACR 70mg/mmol or more
- accelerated disease
- uncontrolled HTN despite 4 or more any-hypertensives
in CKD, what is classed as “accelerated disease”?
one of the following: - eGFR drops by 15 - eGFR drops by 20% - eGFR drops by 15ml/min all within 1 year
how can the progression of CKD be slowed?
- optimise DM and HTN control
- treat glomerulonephritis
how can complications be reduced in CKD?
- exercise to maintain healthy weight
- stop smoking
- special dietary advice on phosphate, sodium, potassium and water intake
- atorvastatin 20mg for CVD prevention
how are complications in CKD treated?
- PO sodium bicarbonate (metabolic acidosis)
- iron and erythropoietin (anaemia)
- vit D (bone disease)
- dialysis / transplant for ESRF
first line drug for HTN in CKD? target BP?
- ACE-i
- <140/90
which electrolyte needs to be monitored closely in someone with CKD and on an ACE-i?
- serum K+
- hyperkalaemia can result from both of these
how does CKD cause anaemia?
healthy kidney cells should produce erythropoietin but they don’t in CKD
How should the iron deficiency in CKD be treated?
- erythropoietin
- IV iron used in dialysis patients
which bone diseases can arise from CKD?
- osteomalacia (softening)
- osteoporosis (brittle)
- ostesclerosis (hardening)
X-ray changes seen in CKD bone disease?
- “rugger jersey”
- sclerosis on both ends of vertebra
- osteomalacia in the middle
how does CKD cause secondary hyperparathyroidism?
the parathyroid glands respond to the low Ca by secreting more PTH
management of renal bone disease in CKD?
- active forms of vit D (alfacalcidol, calcitriol)
- low phosphate diet
- bisphosphates if osteoporotic
AEIOU: indications for acute dialysis in AKI patients
- Acidosis (severe, refractory)
- Electrolytes (severe hyperkalaemia)
- Intoxication (drug OD)
- Oedema (severe, pulmonary)
- Uraemic symptoms
features of uraemia indicating dialysis?
- seizures
- reduced consciousness
2 indications for long-term dialysis?
- ESRF (CKD stage 5)
- any acute indications continuing long-term
what are the 3 main types of dialysis?
- continuous ambulatory peritoneal dialysis
- automated peritoneal dialysis
- haemodialysis
which factors are taken into account when choosing a method for dialysis?
- patient preference
- comorbidities
- individual risks of each type
which factors are taken into account when choosing a method for dialysis?
- patient preference
- comorbidities
- individual risks of each type
complications of peritoneal dialysis?
- bacterial peritonitis
- peritoneal sclerosis
- ultrafiltration failure
- weight gain
- psychosocial effects
which 2 methods are there to access blood flow in order to carry out haemodialysis?
- tunnelled cuff catheter
- AV fistula
complications of an AV fistula?
- aneurysm
- infection
- thrombosis
- stenosis
- STEAL syndrome
- high output heart failure
what is STEAL syndrome?
inadequate blood flow to limb distal to AV fistula (it literally STEALS the blood rip)
describe the scar left by a renal transplant
hockey stick scar over ipsilateral iliac fossa