Saturday, July 25, 2009

QUANTITATIVE ANALYSIS OF PROTEINURIA - Less than 0.5 g/day - (a) Normal, after prolonged exercise, orthostatic. (b) Abnormal - Orthostatic proteinuria

Primary glomerular disease - Minimal change disease, mesangial proliferate GN, focal and segmental GN, membranous GN, megangiocapillary GN, crescentic GN (ii) Secondary glomerular disease - Diabetes, collagen vascular disease, amyloidosis, drugs (gold, penicillamine, mercury). (b) Overflow proteinuria - Multiple myeloma, amyloidosis, myoglobinuria, haemoglobinuria. (c) Tissue proteinuria - Acute inflammation of urinary tract. QUANTITATIVE ANALYSIS OF PROTEINURIA - Less than 0.5 g/day - (a) Normal, after prolonged exercise, orthostatic. (b) Abnormal - Orthostatic proteinuria can occur in mild or resolving glomerular disease. 0.5-2 g/day- (a) Benign - Usually fixed1 i.e. present at all times. (b) Abnormal - Glomerular disease or proximal tubular lesion, congenital or acquired. More than 2 g/day - (a) Glomerular disease. (b) Overproduction of proteins small enough to escape the glomerular barrier e. g. free immunoglobulin light chains produced by a B cell monoclone. Proteinuria more than 5 glday - (with hypoalbuminemia and oedema) - Nephrotic syndrome, specific glomerular disease, accelerated hypertension, unilateral renal artery stenosis, renal venous thrombosis, severe congestive heart failure. Systemic diseases that may present as asymptomatic albuminuria - Diabetes mellitus, amyloidosis, hypertension, gout, SLE. TESTS FOR PROTEIN - (a) Boiling test - For this purpose the urine must be clear, if opalascent it must be filtered. A test-tube is filled with two-thirds urine and the top portion gently heated over a flame, 2 or 3 drops of acetic acid should be added and the urine boiled If turbidity appears in the urine on boiling and it persists after the addition of acetic acid it indicates presence of albumin and the amount of precipitate indicates the amount of albumin. If the turbidity disappears on addition of acetic acid the turbidity is due to phosphates. (b) Dipstick - Test with fresh specimen and ensure that dipsticks are not out of date. (c) Salicylsulphonic acid - The precipitated proteins form a suspension. Mucin - Traces in normal urine. Increased amounts in irritation and inflammation of urinary tract or vagina Sulphonamides - Crystal forms of certain derivatives of sulphonamide may precipitate out from the urine. Fat globules -After ingestion of large quantities of cod liver oil or other fats, phosphorus poisoning and chronic parenchymatous nephritis. In alkaline urine - Phosphates - in osteitis fibrosa cystica, administration of parathyroid hormone, alkalosis, compensatory measure in acidosis to help maintain acid base balance. Calcium carbonate - as amorphous granules, or rarely as colourless spheres and dumb-bells. Ammonium biurate - "Thorn apple" crystals. 2 ERYTHROCYTES -The excretion of erythrocytes should not exceed 1 X 105/ hour. (a) Dysmorphic pattern - Profusion of erythrocytes of bizarre and dissimilar size with variable haemoglobin concentration (Normal upto 8000 urinary erythrocytes). (b) Isomorphic pattern - Non-glomerular bleeding associated with urinary calculi, tumours and papillary necrosis. Erythrocytes which are uniform in size and shape with normal haemoglobin concentration are not a normal component of urine and thus a count as low as 4000/ml may be a sensitive and specific indicator of non-glomerular bleeding. The number of red cells present provides information on the probable type of underlying glomerulonephritis, particularly if haematuria is associated with other urinary abnormalities, such as the presence of protein, fat and casts. Thus a patient with membranous glomerulonephritis has an erythrocyte count of 20,000-50,QQQ/ml accompanied by marked proteinuria, oval fat bodies and many casts containing fat. Mesangial IgA nephropathy is associated with a count of 100,000/ml or more and there may be no fat, casts or protein in urine. An erythrocyte count of more than 1,000,000/ml is likely to reflect the presence of underlying crescents whatever the nature of the glomerular lesion. The dipstick method detects <>

No comments:

Post a Comment