Acute Kidney Injury Flashcards
(34 cards)
What is the difference between acute kidney injury and acute renal failure?
Nothing!
What is AKI?
Acute kidney injury
Abrupt rise in serum urea and creatinine caused by a loss of kidney function that develops within 7 days
What is nephropathy?
Disease of the kidney
What is nephritis?
Nephropathy caused by inflammation
What is nephrosis?
Nephropathy not caused by inflammation
What does the kidney usually do?
Filter blood Clear waste Control blood pressure Help make blood (erythropoietin) Control Ca and K levels
What happens to blood pressure in AKI? Why?
It increases
Could be something to do with the kidney not being perfused as well due to narrowing/damage to blood vessels
So the kidney thinks blood pressure is low and raises it using the RAAS
What categories of causes of AKI are there?
Pre-renal
Intrinsic renal
Post-renal
What is meant by pre-renal causes of AKI?
List some.
Impaired perfusion of the kidneys
Hypovolaemia of any cause
- infection
- haemorrhage
- cardiac failure
- dehydration
- many more
What is meant by intrinsic renal causes of AKI?
List some.
Damage to renal parenchyma
Vasculitis
Glomerulonephritis
Drugs
Ischaemia: due to oxygen deprivation
Obstruction: tumours, casts/plugs in renal tubules
Many more
What are the components of renal parenchyma?
Vessels
Glomeruli (capillaries associated with nephrons)
Tubulointerstitium (tubes where filtering occurs)
What is meant by post-renal causes of AKI?
List some.
Outflow obstruction
Obstruction of ureters, bladder, prostate, urethra
- tumour
- stone
- fibrosis
- benign prostatic hyperplasia
What are the symptoms of uraemia?
Uraemia = urea in the blood
Lethargy Nausea Anorexia Itch Confusion Pericardial rub (caused by pericarditis?
What are the SYMPTOMS of AKI?
Can be asymptomatic
Uraemia related symptoms:
- lethargy
- nausea
- confusion
Systemic features
- rash
- joint pain
- haemoptysis
- bleeding
- oliguria or anuria
What are some risk factors of AKI?
Being elderly Already having CKD Diabetes Prostate cancer Heart failure Sepsis Dehydration
What are the SIGNS of AKI?
Haematuria + proteinuria
Hypertension, raised JVP
Oedema in peripheries and in lungs
Pericardial rub
Abdomen:
- distended bladder
- dull suprapubic percussion
Low O2 stats + high resp rate
What is a pericardial rub?
When does it occur?
Occurs if they are very uraemic
A crunchy snow type noise when listening to heart
Caused by pericarditis, rubbing of the two layers of the pericardium
What should you do immediately if you hear a pericardial rub?
Start dialysis, they are very uraemic
Baseline investigations of AKI?
Blood tests
Urinalysis:
- protein
- blood
USS: look for kidney abnormalities, obstructions,
ECG: to check if high K+ levels are affecting the heart
CXR: look for pulmonary oedema
ABG: look at K+ levels and pH
What blood tests should you do when investigating AKI?
Urea + electrolytes
Glucose: check for diabetes
Liver function
Coagulation
CRP/ESR: look for signs of inflammation
Blood film: look at shape of RBCs, is there anaemia?
Serology: look for autoantibodies
What investigations should you do if the baseline investigations don’t identify a cause of AKI?
Did they have a fall and were lying there for a while? Could be rhabdomyolysis
Have they had any recent chemotherapy or do they have lymphoma? Could be tumour lysis causing intrinsic renal failure
Screen for myeloma
Renal biopsy
What type of investigations should you avoid in cases of AKI?
Contrast imaging
Because contrast will need to be cleared by the kidneys and if they are failing this won’t happen
You’ll get build up of contrast, toxicity
How does myeloma cause renal failure?
Myeloma causes abnormal plasma cells which divide uncontrollably
They release an antibody called paraprotein which builds up in places it shouldn’t
These causes casts or plugs to form in the kidney, impairing its function
What is rhabdomyolysis?
Breakdown / wasting of skeletal muscle
The breakdown products (myoglobin) enter the blood stream and damage the kidney
