Nephrology 1 Flashcards
What is acute kidney injury?
The abrupt loss of kidney function
What can result from acute kidney injury?
The retention of urea and other nitrogenous waste products
The dysregulation of extracellular volume and electrolytes
What is the usual pathophysiology of AKI?
Acute tubular necrosis (ischaemia, from sepsis or shock, or nephrotoxins - aminoglycosides or myoglobin)
Muddy brown casts of epithelial cells
What staging systems are used for AKI in children and adults?
Adults: KDIGO
Children: pRIFLE
How is AKI monitored?
Rise in creatinine
Drop in urinary output
Falling eGFR
Name five pre-renal causes of AKI.
Volume depletion: severe v+d, haemorrhage
Oedematous states: cardiac failure
Hypotension: sepsis, cardiogenic shock
Renal hypoperfusion: ACEIs or ARBs, AAA, renal artery stenosis
Name three renal causes of AKI.
Glomerular disease: glomerulonephritis, HUS
Vasculitis
Ischaemic tubular injury
Name three post renal causes of AKI.
Renal calculus
Blood clot
Pelvic malignancy
Give three risk factors for AKI.
CKD
Nephrotoxic drugs
Previous history of AKI
Name five nephrotoxic drugs.
Diuretics ACEIs Metformin NSAIDs Aminoglycosides
How does AKI typically present?
Oliguria/anuria Rise in serum creatinine Nausea and vomiting Dehydration Confusion
What are the signs of AKI?
Hypertension
Dehydration
Raised JVP and oedema
Define AKI
Rise in serum creatinine of 26umol/L in 48 hours
Drop in urine output to 0.5ml/kg/hr (for 6 hours in adults and 8 hours in children)
Children - fall in eGFR of 25% or more in the preceding 7 days
What urinalysis investigations are required in AKI?
Dipstick for blood, nitrates, leukocytes, glucose, protein
Osmolality
Myoglobinuria
What blood tests are required in AKI?
FBC and film U&Es Coagulation studies for DIC and sepsis CK Immunoglobulins or ANAs
When is ultrasound indicated in AKI?
When obstruction is suspected or no cause identified.
What is the management of electrolytes and fluid balance in AKI?
0.9% saline
Restrict oral potassium/sodium and avoid K supplements
Correct electrolyte imbalances
What are the indications of renal replacement therapy in AKI?
When any of the following are not responding to medical management:
- severe refractory hyperkalaemia (>7mmol/L)
- metabolic acidosis
- fluid overload
- symptoms of uraemia (pericarditis too)
Define chronic kidney disease.
Presence of kidney damage (albuminuria) or decreased kidney function (GFR<60ml/min/1.73m2) for 3 months or longer
Sustained decrease in GFR of 25% or more and a change in GFR category within 12 months is called what?
Accelerated progression of CKD
Define kidney failure.
GFR<15ml/min/1.73m2
OR
Need for RRT
Give three causes of CKD.
Hypertension or diabetes
Infective, obstructive, and reflux nephropathies
Glomerulonephritis
Give five risk factors for CKD.
CVD Diabetes, hypertension, smoking Afro-Caribbean descent FH Proteinuria
How is kidney function assessed?
GFR
Albumin-creatinine ratio
CKD is usually asymptomatic and discovered routinely. What are the symptoms of severe CKD?
Anorexia, nausea, fatigue Weakness and muscle cramps Oedema ---> dyspnoea Nocturia and polyuria Insomnia Headaches Sexual dysfunction
What are the four Ps, signs of CKD?
Pigment: Increased skin pigmentation/ excoriation
Pallor
Pleural effusions/peripheral oedema
Postural hypotension/ hypertension
What is the typical biochemistry results of a patient with CKD?
Plasma glucose: high Serum sodium: low Serum potassium: high Serum bicarb: low Serum albumin: low Serum phosphate: high
Rise in which substances suggests CKD-related bone disease?
ALP
PTH
What sort of anaemia do CKD patients have?
Normochromic normocytic anaemia
What urine investigations are performed for CKD?
Urinalysis
Spot urine collection for total protein:creatinine ratio
ACR
Culture
What typical interventions are used in CKD patients for the following problems?
1) Primary prevention of CVD
2) Hypertension
3) Obesity
4) Prevention of osteoporosis
5) Secondary hyperparathyroidism (from hypocalcaemia)
1) Atorvastatin 20mg and apixaban
2) ACEI and restrict sodium to <2.4g/day
3) 30-35kcal/IBW/day
4) Bisphosphonates
5) Vitamin D supplementation (hypocalcaemia results from low activated form of vitamin D)
What is diabetes insipidus?
Deficiency of ADH (central DI) or insensitivity to its action (nephrogenic DI)