7. Renal Disease Flashcards
Functions of the kidney?
Excretory functions
- Metabolic wastes: urea and creatinine - Bio active substances - hormones, dugs - toxins
Endocrine functions
- Eythopoitnn, renin, prostaglandins
Regulatory Functions
- Water balance - Electrolyte balance and acide base balance
Metabolic Functions
- Vitamin D
Risk factors for Kidney disease?
- pre-existing renal dysfuntion
- sepsis
- old age
- diabetes
- atherosclerosis
- chronic hypertension
medications
- Nonsterodial anti inflammatory drugs
- angiotensin receptor blockers
Procedures
- cardiopulmonary bypass
- liver or kidney transplantation
Steps of urine formation?
Filtration
- Filtration only takes place in the renal corpuscle
Reabsorption
- Occurs when filtered material is moved back into the blood
Secretion
- While secretion removes selected material from the blood and places it in the filtrate
What is AKI
Acute kidney disease = Abrupt decline in renal function leading to an increase in serum concentrations of urea, creatinine and other substances (occurs over a period of days)
Categories of AKI?
Pre renal
= diseases characterized by sudden and severe drop in blood pressure (shock) or interruption of blood flow to the kidneys from severe injury or illness
• If caught in time this can be reversed
Intra renal orr Intrinsic
= diseases involving damage to kidneys by inflammation, toxins, drugs, infection or reduced blood supply
Post renal
= diseases associated with sudden obstruction of the urinary tract (i.e. ureters, urethra etc)
Renal function tests?
- GFR is rate volume per unit time at which ultra filtrate is formed at the glomerulus
o Primary measure of renal function
o Normal is 100-120 mL/min
o Endogenous markers: creatinine, urea - Creatinine clearance is considered the best overall index of renal function
o Full 24 hrs urine collection to quantify creatinine
o Cockcroft-gault provides an estimate of Cr Cl form age, weight, gender and serum creatinine
Drugs in Tripple Whammy ?
- Loop diuretic –> block angiotensin II - lower blood volume
- NSAID –> Block the prostaglandins
- ACE inhibitor or Sartan (angiotensin-receptor blocker (ARB) –> Wash out what produced
This combo of drugs can lead to renal failure, especially in older people usually aim to remove one of these agents
Difference between Cockroft and eGFR renal function tests?
Crokroft
- use weight into calculation
- Most resources provide dosage adjustment based on CrCl
eGFR
- can be obtained without the weight of the patient
- used for categorisation of CKD
- Main advantage is to identify CKD early as CKD is asympotamatic
Management of Anaemia?
= renal failure results in reduced absorption of iron to make RBC
Erythropoietin therapy
- Erythropoietin-stimulating agents (ESA) eg Darbepoetin (Asanesp)
o Monitor Hb 2-4 weekly
- ESA stimulates bone marrow to make RBC
- Iron supplement if necessary
Management of Hyperkalaemia
In CKD potassium usually sits around 6-6.5
- Diuretics
- Risk 7 = immediate calcium gluconate - stabilise heart
- Insulin + glucose - moves potassium back into cells
- resonium
- Stop ACEE inhibitors
Management of Renal Bone disease
- Control Phosphate binders (eg. Calcium carbonate) reduce hyperphosphatasemia e.g. dietary phosphate restriction (avoid dairy)
- Calcitriol improves hypocalcaemia
Drugs that are excreted by the kidneys:
- Bisphosphonates
- Colchicine
- Allopurinol
- Clexane
- Antibiotics: gentamicin, aminoglycosides