Case 3- acute kidney disease and chronic kidney disease Flashcards
Acute kidney disease (AKI)
A sudden episode of kidney injury that happens over a few hours or days. It causes a build up of waste products in your blood and makes fluid balance harder, Can affect other organs like the brain, heart and lungs. It is treatable
Creatine levels and urinary output in AKI
In a blood test where there is an increase in creatine levels 1.5 times the baseline or more than 26.5 micro mol/L within 48 hours. Also reduced urine output at less than 0.5ml/kg/hr for over 6 hours. AKI can lead to CKD, or even acute onset chronic kidney disease.
AKI risk factors
Over 65, history of AKI and CKD, heart failure, liver disease and diabetes. Neurological or cognitive impairment, sepsis, Hypovolemia, oliguria (little urine output) and nephrotoxic drug use within the last week like ace inhibitors. When you are immunocompromised, or can be the result of toxins, cancer and cancer therapy.
3 causes of AKI
Pre-renal, renal and post renal
Pre-renal causes of AKI
Reduction of perfusion to kidneys leading to injury before the kidney. Can be due to cardiac failure or acute coronary syndrome. You can be hypovolaemic for a number of reasons such as diarrhoea or dehydration. Volume can be lost into other tissues such as cirrhosis and nephrotic syndrome. You may have a blocked renal artery such as thrombosis or stenosis but will only affect one kidney. Can be caused by drugs such as ibuprofen or ace-inhibitors (NAIDS). Can also be due to 3rd space loss which is the abnormal accumulation of fluid into an extracellular and extravascular space
Renal causes of AKI
Damage to the kidney last thing to look at. Can be Glomerulonephritis .Could be acute tubular necrosis causing odemia, Hypertension and Haematuria. Vasculitis can occur in the kidney blood vessels which are inflammation based. Can be acute tubular necrosis due to either toxic substances or ischaemia. Can be acute interstitial nephritis
Glomerulonephritis
Inflammation of the Glomerulus, this leads to damage which allows blood and protein to leak into the urine. You have different types: segmental gomerulosclerosis, membranous nephropathy and IgA nephropathy. Can present with isolated haematuria, proteinuria, nephritic and nephrotic syndrome, acute renal failure and chronic renal failure
Post renal causes of AKI
Blockage of urinary track causes a build-up of waste in the kidneys, will eventually cause damage and hydronephrosis. Can be unilateral or bilateral damage. Obstruction at any level such as tumour or stone. This will cause Hydronephrosis where the kidney swells. Blockage of the urethra will cause bilateral Hydronephrosis and will affect both kidneys.
Other causes of AKI
1) Rhabdomyolysis- damage of skeletal muscle release myoglobin into the circulation, it is toxic in the tubule
2) Crush injuries- due to a long-lie from overdose or age, presents with brown “coca-cola” urine
3) Haemolytic uraemic syndrome
Most likely cause of AKI
You first investigate pre-renal causes then post-renal and finally renal causes. Though renal causes are uncommon
Initial investigation in a pre-renal AKI cause
1) Urinary and electrolytes (U+E’s) to confirm AKI.
2) Dipstick analysis/urinary microscopy to detect micro-cultures.
3) Liver function tests and bone profile
4) Full blood count and C-reactive protein test (CRP)
5) ECG and chest X-ray
Investigations for a post renal cause
Ultrasound kidney ureter bladder (KUB) to look for evidence of obstruction like a stone or Hydronephrosis
Investigations for a renal cause
Done after post-renal and pre-renal. Immunology test and vasculitis screen. Renal biopsy may be performed
When is dialyses used?
Criteria is AEIOU Acidosis (7.1pH) Electrolytes (hypercalaemia) Intoxicants (get rid of drugs) Overload (too much fluid) Uraemia (remove urine)
Treatment for post-renal and pre-renal causes
Pre-renal treatment is about blood flow to the kidney and treating the cause, IV fluid is common. Post renal treatment is about removing the obstruction such as a urinary catheter.
