Approach to the patient with hematuria. RBC, red blood cell; WBC, white blood cell; GBM, glomerular basement membrane; ANCA, antineutrophil cytoplasmic antibody; VDRL, venereal disease research laboratory; ASLO, antistreptolysin O; UA, urinalysis; IVP, intravenous pyelography; CT, computed tomography. A detailed discussion of glomerulonephritis and diseases of the microvasculature can be found in Chap. 277. | Chapter 045. Azotemia and Urinary Abnormalities Part 5 Approach to the patient with hematuria. RBC red blood cell WBC white blood cell GBM glomerular basement membrane ANCA antineutrophil cytoplasmic antibody VDRL venereal disease research laboratory ASLO antistreptolysin O UA urinalysis IVP intravenous pyelography CT computed tomography. A detailed discussion of glomerulonephritis and diseases of the microvasculature can be found in Chap. 277. OLIGURIA AND ANURIA Oliguria refers to a 24-h urine output of 500 mL and anuria is the complete absence of urine formation 50 mL . Anuria can be caused by total urinary tract obstruction total renal artery or vein occlusion and shock manifested by severe hypotension and intense renal vasoconstriction . Cortical necrosis ATN and rapidly progressive glomerulonephritis can occasionally cause anuria. Oliguria can accompany any cause of acute renal failure and carries a more serious prognosis for renal recovery in all conditions except prerenal azotemia. Nonoliguria refers to urine output 500 mL d in patients with acute or chronic azotemia. With nonoliguric ATN disturbances of potassium and hydrogen balance are less severe than in oliguric patients and recovery to normal renal function is usually more rapid. Proteinuria The evaluation of proteinuria is shown schematically in Fig. 45-3 and is typically initiated after detection of proteinuria by dipstick examination. The dipstick measurement detects mostly albumin and gives false-positive results when pH and the urine is very concentrated or contaminated with blood. A very dilute urine may obscure significant proteinuria on dipstick examination and proteinuria that is not predominantly albumin will be missed. This is particularly important for the detection of Bence-Jones proteins in the urine of patients with multiple myeloma. Tests to measure total urine concentration accurately rely on precipitation with sulfosalicylic or trichloracetic acids. Currently ultrasensitive .
