31 Urinary diseases 1 Flashcards
What are the functions of the kidney? (4)
Eliminating waster products.
Regulating fluid and electrolyte levels.
Influencing acid-base balance.
Production of erythropoietin and renin.
Which three structures allow filtration in the kidney?
Podocyte foot processes.
Basement membrane.
Endothelial cells.
What are the immunological mechanisms of glomerular damage? (2).
Deposition of circulating immune complexes/ antigens.
Autoantibodies to components of glomerulus.
What are the non immunological mechanisms of glomerular damage? (4).
Injury to endothelium.
Altered basement membrane due to hyperglycaemia in diabetes.
Abnormal basement membrane/podocyte structure.
Deposition of abnormal proteins.
What are the mechanisms of tubular damage in the kidney? (7)
Ischaemic: hypotension, damage to vessels, glomerular damage.
Toxic: direct, hypersensitivity, protein deposition, crystal deposition (gout).
Describe how microthrombotic angiopathy induces vascular damage in the kidney.
Damage to endothelial wall leads to thrombi in capillaries and small arterioles.
Abnormal clotting proteins, bacterial drugs and toxins.
What is nephrotic syndrome?
Simple cause?
Oedema, proteinuria, hypoalbuminaemia.
±hypertension ± hyperlipidaemia
Always due to glomerular damage.
What are the common causes of nephrotic syndrome in adults? (6).
Membranous nephropathy. M>F. Most common.
Focal segmental glomerulosclerosis. M>F.
Minimal change disease.
Amyloid, diabetes, lupus nephritis.
What are the most common causes of nephrotic syndrome in children? (2).
Minimal change disease. Most common.
Focal segmental glomerulosclerosis.
What is acute nephritis? (5)
Oedema. Haematuria. Proteinuria. Hypertension. Acute renal failure.
What are the most common causes of acute nephritis in adults? (4).
Post-infective glomerulonephritis (strep throat).
IgA nephropathy (teens with haematuria).
Vasculitis (+ rash, myalgia, arthralgia).
Lupus (young women).
What are the common causes of acute nephritis in children? (4).
Post-infective glomerulonephritis.
IgA neuropathy.
Henonch-Schonlein purpura. Specific IgA nephropathy. M>F.
Haemolytic uraemia syndrome (E.coli O157 enteritis + haemolysis + thrombocytopenia).
What is the diagnostic criteria for acute renal failure?
Anuria/oliguria and raised serum creatinine/urea.
What are the general causes of acute renal failure? (4)
Pre renal: dehydration, any hypotensive cause.
Renal.
Post renal: urinary obstruction: tumour, bladder stones, prostate enlargement.
What do biopsies of kidneys with acute renal failure show?
Acute tubular necrosis.
What are three causes of acute renal failure in adults?
Vasculitis.
Acute interstitial nephritis.
Acute tubulointerstitial nephritis (mostly drug rxns).
What are the three causes of acute renal failure in children?
Henonch-Schonlein purpura.
Haemolytic uraemic syndrome.
Acute interstitial nephritis.
What are the complications of acute renal failure? (5).
Cardiac failure (fluid overload). Arrythmias (electrolyte imbalance). GI bleeding. Jaundice (hepatic venous congestion). Infection, especially lung and urinary tract.
What is chronic renal failure?
Permanently reduced glomerular filtrate rate.
Reduced number of nephrons.
What are the common causes of chronic renal failure in adults?
Diabetes.
Glomerulonephritis.
Reflux nephropathy (reflux-infection-scarring).
Why is a biopsy unhelpful in end stage renal disease?
Will show the same regardless of cause.
Scarring with loss of glomeruli and tubules.
What are the systemic effects of chronic renal failure?
Reduced excretion - oedema, hypertension.
Reduced toxic metabolite excretion.
Reduced production of erythropoietin - anaemia.
Renal bone disease.
What are the causes of isolated haematuria ± proteinuria with normal kidney function? (3).
IgA nephropathy.
Thin basement membrane disease.
Alport type hereditary nephropathy. Collagen IV defect. ± deafness, ± ocular problems.
What are the causes of isolated proteinuria?
3 benign, 4 diseases
Benign: postural, pyrexia, exercise.
Disease: FSGS, Diabetes, Lupus, Henoch-Schonlein purpura.
What is acute pyelonephritis associated with?
Women.
Diabetes.
Structural urinary tract abnormalities.
What is chronic pyelonephritis associated with?
Obstruction of urinary tract and fibrosis.
How does renal artery stenosis affect the kidney? (2)
Causes infarction, killing kidney tissue.
Activates RAAS system, causing hypertension.
How does hypertension affect the kidney? (3)
Damages vessel walls leading to increased thickness and reduction in lumen.
Induces chronic hypoxia which leads to loss of renal tubules.
Reduction in flow activates RAAS, exacerbating the hypoxia.
How does diabetes affect the kidney? (3)
Hyperglycaemia damages the basement membrane, becoming thicker.
Glomerulus produces extra extracellular matrix, forming nodules.
Small vessel damage leading to ischaemia.
How does myeloma affect the kidney?
Excess immunoglobulin production. Deposition in the kidney tubules, causing inflammation and fibrosis.
Renal impairment is irreversible.
Name toxins that directly damage kidney tubules (6).
Drugs e.g. antibiotics, NSAIDs. Organic solvents. Heavy metals. Ethylene glycol (anti-freeze). Pesticides. Iodine containing radiographic contrast medium.
