investigations for nephrotic syndrome

Pcl 11_investigations and blood test for the nephritic syndrome

Ix
URINE analysis : determination of urine production rate and concentrating power of the kidneys; investigation of urinary tract infections; urinary protein indicates integrity glomerular filter; exclusion of diabetes mellitus; investigation of glomerular or tubular lesions
· dipstick( haematuria and proteinuria)
o reagent strips mainly detect raised albumin levels in urine (100-200 mg/L)
o if proteinuria is confirmed on repeated testing, 24 hr urine collections should be done

· Microscropy (RBCs, casts)
o Casts: cylindrical bodies in the shape of a tubular lumen
o 3 types: hyaline, granular or cellular
o Hyaline and fine granular casts represent precipitated protein and may be seen in normal urine, especially aftyer exercise
o Course granular casts occur with pathological proteinuria in glomerular and tubular disease
o Red cells casts are always indicative of renal disease
· Culture/sensitivity
· 24hr collection

BLOOD analysis: determination of integrity of renal function; glomerular filtration rate can be calculated from urinary and plasma creatinine concentration and urinary flow.
*full blood count
*blood test: for this case, plasma albumin, LDL,VLDL, HDL and glucose levels would be relevant
*Urea and electrolytes and creatinine in plasma
*Liver function test
*Erythrocyte sedimentation rate
*C- reactive protein
*Cholesterol: increase in low density lipoprotein, very low density lipoprotein, and/or intermediate density lipoprotein but no change in high density lipoprotein, resulting in an increase of the LDL/HDL cholesterol ratio.
*Immunoglobulins
*Serum electrophoresis
*Complement ( C3 and C4)
*Autoantibodies

IMAGING: determination of kidney size and symmetry; investigation of suspected tumours, cysts; etc; detection of calculi; position and integrity of ureters
*X-rays: chest x-ray may show cardiomegaly, pulmonary oedema, plain x-ray
*Renal ultrasound

RENAL BIOPSY
Carried out under ultrasound control
Helpful in investigation of nephrotic syndrome




Albumin
· Protein made in the liver
· Most abundant protein in the blood \Mostly responsible for oncotic pressure
· Used in transport of various substances (so they can be plasma soluble)
· More studies show that early detection of kidney disease (eg. via urine tests) ® Much better outcomes
Albumin in the urine is classified by quantity:
– Microalbuminuria = 30-300mg/24hrs
– Macroalbuminuria = >300mg/24hrs
– Proteinuria = >3g/24hrs

Glomerular Filtration Rate (GFR) = Rate that plasma is filtered through the glomeruli in the kidneys. Clinically we use Creatinine Clearance as a measure of GFR.
Creatinine Clearance = amount of plasma cleared of creatinine in one minute (we use creatinine because it is not really reabsorbed and only a little secreted).
– Normal Male = 90-140mL/min
– Normal Female = 80-125mL/min
Clearance (mL/min) = (U x V)/P where U = [Creatinine] in urine
V = Rate of urine output (mL/min)
P = [Creatinine] in plasma
**Note that serum creatinine will only begin to rise when Renal Fn has decreased to ~50%. Remember the exponential graph depicting a rise in Serum [Cr] after 50% loss of function
\Normal Serum [Cr] ¹ Normal Renal Fn.