AKI & CKD Flashcards by Yasmin Kamara

What is a normal GFR?

120mls/ min

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What is the gold-standard measure of GFR?

Inulin clearance

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give 3 clinically-viable exogenous markers of GFR?

51Cr-EDTA - Edetate Chromium
99Tc-DTPA - diethylene-triamine-pentaacetate)
Iohexol

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what equation uses plasma creatinine to estimate GFR?

Clearance = (U x V)/P
concentration of creatinine in urine = U
concentration of creatinine in plasma = P
volume of urine collected in T minutes = V

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why does plasma urea have a limited clinical value for measuring renal function?

variable (30-60%) reabsorption by tubular cells

dependent on nutritional state, hepatic function, GI bleeds

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describe the movement of creatinine from blood to urine

Freely filtered
Actively transported into urine by tubular cells

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what formula estimates clearance using serum creatinine concentration?

Cockcroft Gault Equation

(eCCR)

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what cells produce cystatin C & how is it correlated w GFR?

produced by all nucleated cells
freely filtered at glomerulus
almost completely reabsorbed by tubular cells
inversely correlated w GFR

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In what 3 circumstances does cystatin C not give a reliable result for GFR estimation?

hyperthyroidism
malignancy
corticosteroids

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How can proteinuria be quantified?

Spot urine measurement

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what can a 24-hour urine collection be used for?

Creatinine clearance estimation
Examination for stone-forming elements
Proteinuria quantification (but this can also be done on spot urine testing)
Electrolyte estimation (but this can also be done on spot urine testing)

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what is the first choice of imaging in a suspected renal stone?

CT KUB
2nd = USS KUB
plain KUB may show stag horn calculi

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what is the first choice of imaging to assess renal blood flow?

USS with doppler

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what is the first choice of imaging in investigating renal structural abnormalities?

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recall the increases in creatinine that define each stage of AKI

Stage 1: 1.5-1.9 x the reference
Stage 2: 2-2.9 x the reference
Stage 3: >=3 x the reference (or >354)

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recall 5 differentials for pre-renal AKI

true volume depletion e.g haemorrhage in accident
hypotension
oedematous state (heart failure)
renal artery stenosis
drugs

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Recall 5 drug classes that can predispose to pre-renal AKI and the mechanism of each of these

ACEi & ARBs - decrease efferent constriction
NSAIDs & Calcineurin inhibitors - decrease afferent arteriolar dilatation
Diuretics: decrease pre-load

When does AKI become only partially reversible?

When acute tubular necrosis occurs

recall 5 differentials for the causes of post-renal AKI

It’s an obstructive pathology:

kidney stone
bilateral ureteric obstruction (BPH)
cancer of pelvis, colon or cervix
ormond’s disease - Retroperitoneal fibrosis
blocked urinary catheter

recall 4 causes of intrinsic renal AKI

vascular causes (vasculitis/ vasculitides)
glomerular (glomerulonephritis)
tubular (ATN)
interstitial (analgesic nephropathy)
abnormal protein deposition- myoglobin (rhabdomyolysis), immunoglobin (amyloidosis - nephrotic syndrome, myeloma)
drugs - aminoglycosides (gentamicin etc), amphotericin, aciclovir

what is the most common cause of intrinsic renal AKI?

Acute tubular necrosis

what are the 2 best measures of AKI severity?

Creatinine
Urine output

how is CKD stage 1 defined?

Kidney damage with normal GFR (>90)

how is CKD stage 5 defined?

End-stage kidney failure - GFR <15 or dialysis

What is the best measure of prognosis in CKD?

Albumin creatinine ratio

What is the most common cause of CKD?

Diabetes by a long mile

how can CKD cause a failure of homeostatsis as a first consequence?

1a- Can cause acidosis due to reduced H+ excretion 1b Can cause hyperkalaemia due to reduced K+ excretion

how can CKD cause a failure of hormonal function as a second consequence?

2a- Can lead to a normochromic normocytic anaemia due to failure of EPO production 2b- Can cause reduced bone density due to failure of PTH action Buildup of phosphorus is associated with less calcium in your blood and with the release of PTH by your parathyroid glands. PTH moves calcium out of your bones and into your blood. The loss of calcium can harm your bones.

how can end-stage CKD affect the heart as a third & most important consequence?

\> uraemic cardiomyopathy

how should renal bone disease be treated (3 ways)?

1. Phosphate control (phosphate binding drugs) & diet 2. Vitamin D receptor activators (eg alfacalcidiol, paracalcitol) 3. PTH suppression (cinacalcet - increases sensitivity of CaSr)

how is CKD stage 2 defined?

GFR between 60-89

how is CKD stage 3 defined?

GFR between 30-59

how is CKD stage 4 defined?

GFR between 15-29

give 5 causes of CKD

diabetes hypertension polycystic kidney disease chronic glomerulonephritis infective or obstructive uropathy

what's the fourth & final consequence of CKD

uraemia & death

how does CKD cause renal bone disease?

Renal osteodystrophy has been classically described to be the result of hyperparathyroidism secondary to hyperphosphatemia combined with hypocalcemia, both of which are due to decreased excretion of phosphate by the damaged kidney Unable to: excrete phosphate from kidneys / make vitamin D lower vitamin D leads to 2nd HPT Excess phosphate complexes with Ca2+ causing hypocalcaemia Phosphate-calcium crystals deposit = renal osteodystrophy bone diseases linked to CKD = osteitis fibres cystica, osteomalcia

what is the treatment of anaemia due to CKD?

TREATMENT: use artificial erythropoiesis-stimulating agents (ESAs) Erythropoietin alfa (Eprex) Erythropoietin beta (NeoRecormon) Darbopoietin (Aranesp)

what's the treatment of acidosis due to CKD?

oral sodium bicarbonate

what dietary measures should be taken by those with CKD?

avoid foods rich in potassium = chocolate, tomatoes, milk, dried fruits.

outline 3 treatment options in CKD?

transplantation haemodialysis peritoneal dialysis

what's a contraindication for transplantation?

active sepsis not HIV, high BMI, age or malignancy

what are 5 indications for dialysis?

Refractory hyperkalaemia Refractory fluid overload Metabolic acidosis Uraemic symptoms (encephalopathy, nausea, pruritis, malaise, pericarditis) CKD stage 5 (GFR \<15mL/min)