Systems Pathology: Kidney Failure Flashcards
Acute kidney injury
Total renal failure
Sudden
High morality and common
Oliguria (decreased )leading to anuria (none)
Electrolyte imbalance-> Hyperkalaemia and metabolic acidosis-> can’t compensate
Rapidly raising blood urea and creatine and nitrogen
Kidney functions
Excretion of nitrogenous waste
Salt, ion and water homeostasis
Secretion of erythropoietin
Secretion of renin
Diagnosis of acute kidney injury
Serum creatine rises by 26 mmol in 48 hours
Serum creatine rise by 1.5 fold in a week
Urine output <0.5 ml/kg/h for more than 6 hours
Causes of acute kidney injury, pre renal
Pre renal causation
-> Hypovolemic shock, haemorrhage, cardiac failure
-> reduced renal perfusion
-> kidneys attempt to retain sodium and water-> RAA
-> renal excretory capacity is impaired
Teat by increasing perfusion pressure
Acute tubular necrosis
Tubular epithelial cells have high O2 demands
Central perfusion failure
Proximal and distal tubules most vulnerable
Tubular cells die-> no ion or water pumping-> kidneys swell
Most common cause of acute reversible kidney failure
Glomerular disease
Glomerulonephritis
Immune complex mediated damage when all glomeruli damaged at the same time
-> rapidly progressive
-> post infective
-> or linked to vasculitis
Occlusion of glomerular capillaries prevents ultrafiltration and also prevents blood flow though efferent arteriol-> reduced O2 to kidney-> AKI
Nephritic syndrome->obliteration or glomerular lumina
Vascular causes of AKI
Vasculitis-> immune mediated inflammation and destruction of small vessels
Disseminated intravascular co agulation
Malignant hypertension
Tubular and intersitial disease
Nephrotoxins Infective damage-> acute pyelonephritis Immune mediated Hypoxia -> whole nephron fails without tubule
Post renal AKI
Acute obstruction of lower urinary tract-> prostate -> ureters Lumen-> stone Wall-> tumour or inflammation Extrinsic-> massive tumour
Chronic renal failure
Slowly progressive and irreversible loss of enable function due to irreversible destruction of large numbers of nephrons
Lots of nephrons so gradual deterioration
Symptoms appear when compensation fails
Symptoms of renal failure
Insidious onset, variable symptoms
Polyuria
Malaise, lethargy
Increasing uraemia-> bone marrow suppression and platelet dysfunction
Confusion and eventual coma
Electrolyte imbalance
Na and water retention
Hypertension
Failure of renal activation of vit D-> secondary hyperparathyroidsim and bone disease
Destruction of parenchyma-> reduced erythropoietin-> anaemia
CKD initiating factors
Age Family history Nephrotoxins Diabetes mellitus Urinary infections, obstruction Cardiovascular disease
CKD perpetuating factors
Hypertension Proteinuria Obesity Anaemia Nephrotoxins Cv diseased Smoking
Causes of CKD
Diabetic kidney disease Congenital kidney disease Immunological damage to glomerulus-> glomeruli nephritis Chronic renal reflux Infection-> hep b,c, malaria, TB, HIV
Partial renal failure syndrome
Nephritic syndrome-> disturbance of glomerular structure-> reactive cellular proliferation
-> reduced glomerular blood flow-> oliguria, hematuria, uraemia
-> RAA activation-> fluid retention and hypertension
Necrotic syndrome-> abnormality in glomerular basement membrane or mesangium-> loses capacity for selective filtering
-> protienuria, hypoalbuminemia, edema
-> susceptibility to infections, thrombosis and hyperlipideamia
