Chronic Kidney Disease Flashcards
(30 cards)
What are some of the main functions of the kidneys?
Bod fluid homeostasis
Regulation of vascular tone
Excretory function
Electrolyte homeostasis
Acid base homeostasis
Endocrine function
How do we assess for kidney disease?
Filtration function (excretory) - remove
Filtration function (barrier) - retain
Anatomy - abnormality
What is the GFR?
Pressure difference leads to glomerular filtration
Normal is 120ml/min
How do you measure excretory renal function?
Insulin clearance
Isotope GFR
24 hr urine collection plus blood test
GFR estimating equations
Creatinine measurement
What is the problem when measuring creatinine and GFR?
Creatinine is generated in breakdown of muscle and not everyone has the same muscle mass
What does serum creatinine and GFR depend on?
Age, ethnicity, gender, weight and other issues (ex. liver disease)
What are some names of the formulae used to estimate GFR from serum creatinine?
Cockcroft Gault
MDRD 4 variable equation
CKD-EPI equation - most accurate
Describe the international CKD classification system
Stage 1 - >90 GFR kidney damage
2 - 60-89 GFR kidney damage
3a - 45-59 GFR
3b - 30-44 GFR
4 - 15-29 GFR
5 - <15 advanced or on dialysis
What crosses and does not cross the GBM?
Can cross - water, electrolytes, urea and creatinine
Crosses but reabsorbed in proximal tubule - glucose and low molecular weight proteins
Not cross - cells and high molecular weight proteins (albumin and globulins)
How is kidney filtering function assessed?
Urinalysis - urine dipstick looking for blood and proteins
Protein quantification - protein creatinine ration PCR
What is the current CKD definition?
Either a presence of kidney damage (abnormal blood, urine or x-ray findings) or GFR <60ml/min/1.73m2 that is present for more than 3 months
What helps classify CKD?
GFR values and albuminuria
What is the prevalence of CKD?
Increases with age
8-12% of the UK
Why is CKD important?
Renal replacement therapy
Dialysis is £35000/patient/year
£6500 for drug cost a patient
£20000 per patient transplant
Describe the aetiology of CKD
Diabetes, glomerulonephritis, hypertension, renovascular disease and polycystic kidney disease
What is the clinical approach for CKD?
Detection of underlying aetiology
Slowing the rate of renal decline
Assessment of complications related to reduced GFR
Preparation for renal replacement therapy
What are some symptoms and signs of CKD?
Hypertension, SOB, itch and cramps, haematuria, proteinuria, peripheral oedema, change in urine output, GI symptoms and cognitive changes
What can be included in the history and examination of CKD?
Previous renal disease, FH, systemic diseases, drug exposure, pre-post renal factors and uraemic symptoms
Vital signs, volume status, systemic illness and obstruction
How is underlying aetiology of CKD detected?
Blood tests - U+Es and FBC
Urine tests - urine dip and PCR
Histology - renal biopsy
Radiology
What chemistry investigations detect aetiology?
Urea, creatinine, electrolytes, bicarbonate, total protein, calcium, phosphate, LFTs, creatine kinase, and immunoglobulins
What haematology investigations detect aetiology?
FBC - Hb, MCV, WBC, MCH, platelets and RBCs
Coagulation screen
What might be the only symptom in CKD?
Often asymptomatic
Only sign may be abnormal BP or urinalysis
What imaging is used for CKD?
US - shows shrunken kidneys and if no differentiation between cortex and medulla
How is pathology investigated for CKD?
Kidney biopsy
