3.1. Kidney Injury - Acute Kidney Injury Flashcards
What is Acute Renal Disease?
The Rapid loss of Glomerular Filtration and Tubular Function over hours-days.
What fraction of Hospital admissions are complicated by this?
1/7
What are risk factors for developing an Acute Kidney Injury?
- Age
2. Underlying predisposign conditions (e.g. Diabetes)
What are the 3 types of Renal Disease?
- Pre-Renal - Blood Flow to the Kidney (Common)
- Renal (Intrinsic) - Damage to the Kidney Parenchyma
- Post-Renal - Obstruction to the Urine Exit (Common)
What are causes of Pre-Renal Acute Kidney Injury?
- Sepsis - Major contributor (50% of cases of AKI)
- Hypotension / Renal Artery Occlusion
- Hypovolaemia / Shock
- Hepato-renal Syndrome (Liver Failure)
- Congestive Cardiac Failure
What are causes of Renal Acute Kidney Injury?
- Acute Tubular Injury
- Tubulointerstitial Injury
- Glomerulonephritis
- Myeloma
- Vasculitis
What are causes of Post-Renal Acute Kidney Injury
- Kidney Stones
- Intramural Obstruction
- Extramural Obstruction
What are some aetiologies of Hypovolaemia (causing Pre-Renal Acute Kidney Injury)?
- Haemorrhage
- Burns
- Diuretics
- Vomiting / Diarrhoea
What are some aetiologies of Acute Tubular Injury (causing Renal Acute Kidney Injury)?
- Ischemia
- Pre-Renal Acute Kidney Injury
- Nephrotoxins
What is a cause of Tubulointerstitial Injury (causing Renal Acute Kidney Injury)?
Acute Interstitial Nephritis
What are some aetiologies of Vasculitis (causing Renal Acute Kidney Injury)?
- Lupus
2. Anti-Neutrophil Cytoplasmic Antibodies (ANCA)
What are some aetiologies of Kidney Stones (causing Post-Renal Acute Kidney Injury)?
- Calculus
- Clot
- Sloughed Papilla
What are some aetiologies of Intramural Obstruction (causing Post-Renal Acute Kidney Injury)?
- Malignancy
- Ureteric Stricture
- Prostatic Disease
What are some aetiologies of Extramural Obstruction (causing Post-Renal Acute Kidney Injury)?
- Retroperitoneal Fibrosis
2. Malignancy
What are the 4 Stages in the course of Acute Kidney Injury?
- Preventative Stage
- Management Stage
- Complications
- Death
What is the Preventative Stage?
There is a Normal Kidney which may be exposed to increase risk of Kidney Disease
What is the Management Stage?
Damage has occurred to the Kidney resulting in a decreased Glomerular Filtration Rate.
Note - This can lead to Complications and Kidney Failure
What is the Complications Stage?
These include the list of Complications which can occur due to the Acute Kidney Injury
Why can Death Occur?
Due to the Kidney Failure, or the Complications associated with the damage to the Kidney
When the Injury is initiated, what is it initiated by? And is the Acute Kidney Injury still preventable?
The aetiology (e.g. Toxins / Ischemic Insult) It is still potentially preventable as the Renal Parenchymal Injury will still need (and continue) to evolve
When is the patient usually maximally oliguric?
During the management stage when established Parenchymal Injury has occurred
Does the Kidney have the potential to regenerate?
Yes, resulting in a gradulal increase in urine output and decrease in serum creatinine
What are the Clinical Features of Acute Kidney Injury?
- Rapid Loss of Glomerular Filtration
- Rapid Loss of Tubular Function
- Retention of Urea
- Retention of Creatinine
- Oliguria
What investigations are necessary for Acute Kidney Injury?
- Detailed History / Examination
- Blood Tests
- Urinalysis (Urine Dipstick)
- Ultrasound Scan
- Renal Biopsy
What is the purpose of a Detailed History / Examination?
- To identify the insult (i.e. Drug)
2. To observe the Fluid Status / Urinary Obstruction etc
What Blood Tests will be Performed?
- Serum Creatinine
- Full Blood Count
- Urea and Electrolytes (Including Bicarbonate and Calcium)
- Liver Function Test (and Biochemistry)
- Coagulation Screen
- Arterial Blood Gas
- Serum Anti-Neutrophil Cytoplasmic Antibodies test
What is the purpose of the Blood Tests?
- To assess renal function (serum creatinine)
2. To try to identify any other potential cause
What is the purpose of the Urinalysis (Urine Dipstick)?
To identify Haematuria, and Proteinuria
What is the purpose of the Ultrasound Scan?
To try and find any Post-Renal causes of Acute Kidney Injury
What is the purpose of the Renal Biopsy?
To confirm the Diagnosis
How many stages are there in the KDIGO (Kidney Disease; Improving Global Outcomes) classification?
3
What is defined as a Stage 1, in the KDIGO (Kidney Disease; Improving Global Outcomes) classification, in terms of Creatinine / Urine Output?
Serum Creatinine:
a) 1.5 - 1.9 x the baseline
OR
b) Greater than 26.5 μmol/l increase
Urine Output:
Less than 0.5ml/kg/h for 6 - 12 hours
What is defined as a Stage 2, in the KDIGO (Kidney Disease; Improving Global Outcomes) classification, in terms of Creatinine / Urine Output?
Serum Creatinine:
a) 2.0 - 2.9 x the baseline
Urine Output:
Less than 0.5ml/kg/h for more than 12 hours
What is defined as a Stage 3, in the KDIGO (Kidney Disease; Improving Global Outcomes) classification, in terms of Creatinine / Urine Output?
Serum Creatinine: a) more than 3.0 x the baseline OR b) An incraesed to 354μmol/l OR c) Initiation of Renal Replacement Therapy
Urine Output:
Less than 0.5ml/kg/h for 6 - 12 hours
What are the Treatments of Acute Kidney Injury?
- Anticipation and Prevention of AKI
- Treat the Underlying Cause (e.g. stop nephrotoxic drugs)
- Specific Treatments
a) Pre-Renal
b) Renal
c) Post-Renal - Renal Replacement Therapy
What is included in the Pre-Renal Specific Treatments?
- Fluid Balance - Volume Resuscitation / Fluid Restriction
2. Blood Pressure Support - Vasopressors / Stop Anti-Hypertensives
What is included in the Renal Specific Treatments?
Removal of the Precipitant:
- Treat Sepsis
- Stop taking causative Drugs
- Diagnosis of Glomerulonephritis made
What is included in the Post-Renal Specific Treatments?
- Haemodialysis - Solute removal by diffusion (intermittent therapy)
- Haemofiltration - Solute removal by convection (continuous therapy)
What acronym does the overall treatment of Acute Kidney Injury follow? And what does it stand for?
STOP: Sepsis Toxins Optimize Blood Pressure Prevent Harm
What Complications fall under the “Prevent Harm” section of the “STOP” acronym for the management of Acute Kidney Injuries?
A, E, I, O, U: Acidosis Electrolyte Imbalance (Hyperkalaemia) Intoxication (Toxins - Use antidote / RRT) Overload (Pulmonary Oedema) Uraemic Complications (Pericarditis)
