Lecture 22 : Kidney Injury

Question 1

Kidney Functions

Answer 1

Homeostasis: water, electrolytes, acid-base balance

Waste elimination: urea, creatinine, urate, phosphate

Blood pressure control: via renin-angiotensin system

Hormone synthesis: erythropoietin, vitamin D (activation), renin

Drug metabolism/excretion

Question 2

Chronic Kidney Disease (CKD)

Answer 2

Gradual, irreversible loss of function

Common causes: diabetes, hypertension

Often unrecognised in early stages

Leads to: anaemia, cardiovascular disease, bone disease

Question 3

Acute Kidney Injury (AKI)

Answer 3

Rapid decline in function (hours to days)

Often reversible

Causes: systemic illness, medications, dehydration, sepsis

Risk factors: age, diabetes, CKD, heart/liver disease, polypharmacy

Question 4

Consequences of Kidney Failure

Answer 4

Fluid overload: oedema, hypertension

Electrolyte imbalance: hyperkalaemia → arrhythmias

Acid-base imbalance: acidosis → dyspnoea, enzyme dysfunction

Anaemia: ↓ erythropoietin → fatigue, LV hypertrophy

Toxin accumulation: uraemia → confusion, pericarditis

Impaired drug clearance → toxicity

Question 5

Renal Replacement Therapy (RRT)

Answer 5

Indicated when kidneys can’t maintain homeostasis or excrete waste

Types:

Haemodialysis: blood filtered via machine (hospital-based, ~3x/week)

Peritoneal dialysis: uses peritoneum as membrane (home-based)

Transplant: restores full kidney function

Conservative care: palliative approach

Question 6

Dialysis

Answer 6

Semi-permeable membrane separates blood and dialysis fluid

Removes: urea, H⁺, excess fluid, electrolytes

Not as effective as native kidneys (GFR <15 ml/min equivalent)

Question 7

Kidney Transplant

Answer 7

First-line for end-stage renal failure (CKD stage 5)

Benefits: improved life expectancy and quality of life

Sources: deceased (brain-dead, non-heart-beating) or living donors

Requires immunosuppressants: steroids, calcineurin inhibitors