7. Renal Disease

Question 1

Functions of the kidney?

Answer 1

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

Question 2

Risk factors for Kidney disease?

Answer 2

• 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

Question 3

Steps of urine formation?

Answer 3

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

Question 4

What is AKI

Answer 4

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)

Question 5

Categories of AKI?

Answer 5

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)

Question 6

Renal function tests?

Answer 6

• 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

Question 7

Drugs in Tripple Whammy ?

Answer 7

• 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

Question 8

Difference between Cockroft and eGFR renal function tests?

Answer 8

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

Question 9

Management of Anaemia?

Answer 9

= 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

Question 10

Management of Hyperkalaemia

Answer 10

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

Question 11

Management of Renal Bone disease

Answer 11

• Control Phosphate binders (eg. Calcium carbonate) reduce hyperphosphatasemia e.g. dietary phosphate restriction (avoid dairy)
• Calcitriol improves hypocalcaemia

Question 12

Drugs that are excreted by the kidneys:

Answer 12

• Bisphosphonates
• Colchicine
• Allopurinol
• Clexane
• Antibiotics: gentamicin, aminoglycosides