Kidney diseases Flashcards
Kidney’s principal function
- Eliminating waste materials
- Regulating fluid & electrolyte balance as well as acid-base balance
- Endocrine function eg. prostaglandins, erythropoietin
What are most kidney diseases associated with?
abnormalities of the glomerular capillary or the renal tubule system
What type of reactions are kidneys associated with?
various immune reactions
- immune complexes deposited in the glomerular capillary walls
Example of diseases of the kidney
glomeruli
- immunologically mediated
tubules
- toxic/infectious agents
interstitium
- toxic infectious agents
blood vessels
- decreased blood supply = damage
What happens if there is severe damage to all four structures of the kidney?
chronic renal diseases
which leads to renal failure
Nephritis
inflammation of any part of the kidney
Three types of nephritis
- glomerulonephritis
- interstitial nephritis
- pyelonephritis
Glomerulonephritis
general term for a group of disorders
- bilateral, symmetrical immunologically mediated injury to the glomerulus
How many cases does glomerulonephritis account for of terminal renal failure?
1/3
Primary Glomerulonephritis
kidney is the predominant organ involved
eg. post-streptococcal glomerulonephritis
Secondary Glomerulonephritis
systemic diseases with glomerular involvement
eg. SLE
Renal Failure
failure of renal excretory function due to depression of GFR
What is renal failure accompanied by? (variable extend by failure of)
- erythropoietin (EPO) production
- Vit D hydroxylation
- regulation of acid-base balance
- regulation of salt and water balance and blood pressure
Acute Renal Failure - Pathogenesis
reduced excretion of nitrogenous waste products - urea
uraemia increases creatinine
Acute Renal Failure
abrupt deterioration in parenchymal renal function usually reversible over days or weeks
Acute Renal Failure - Causes
pre-renal
intrinsic renal
post-renal
Percentage of Acute Renal Failure being pre-renal
70%
Percentage of Acute Renal Failure being post-renal
5%
Percentage of Acute Renal Failure being intrinsic renal
25%
Acute Renal Failure - symptoms
early stages often asymptomatic
Acute Renal Failure - when it is symptomatic
when plasma urea > 40mmol/L
− Oliguria, oedema
− Plasma creatinine rises (by ~ 100 roughly mol/day)
−Hyperkalaemia & metabolicacis
− Uraemic syndrome: anorexia, nausea, vomitting, irritability, seizures and coma
Acute Renal Failure - Treatment
- Correct reversible underlying factors
eg. volume depletion, nephrotoxic drugs - Treat hyperkalaemia
- Dialysis
-> Indications:
Hyperkalaemia (> 6.5 mmol/L )
Severe metabolic acidosis (pH <7.2)
Pulmonary oedema
Complications of uraemia: encephalopathy, seizures, pericarditis
Chronic Renal Failure
Long standing and usually progressive impairment in renal function
What are the major causes of chronic renal failure?
Diabetes
Hypertension
Glomerulonephritis
Pyelonephritis
Cystic (polycystic) renal disease
Nephrotoxins
Chronic Renal Failure - Clinical Features
- very insidious
- often asymptomatic until GFR < 15ml/min
- symptoms occur when serum urea >40mmol/L
uraemia syndrome
nocturia and polyuria
oedema
uraemia syndrome
-> nervous system - loss of appetite and energy
-> gastrointestinal - vomiting, nausea
-> dermatological - itching
Chronic Renal Failure - anaemia
- Largely due to EPO deficiency
- Normochromic, normocytic
- Typical “anaemia of chronic disease”
- responds to EPO
Chronic Renal Failure - Electrolyte/acid-base disorders
Hyperkalaemia; Na retention (usually) Hypo~ (early) & hyper~ (late) -calcaemia
metabolic acidosis
Chronic renal failure
- haematological and metabolic complications
anaemia
renal osteodystrophy
Electrolyte/acid-base disorders
