Q3.A patient has normal blood glucose level as estimated by Glucose –Oxidase Peroxidase
method, shows positive Benedicts test in urine.Which of the following is likely cause?
a) Fructosemia
b) Galactosemia
c) Latent Diabetes Mellitus
d) ?Glucose Intolerance
EXPLN
This qn seems to be easy on first look but tricky.The patient has normal blood glucose,but
urine reducing substance is positive.
The problems are age of the patient not mentioned. Assoc clinical symptoms not
mentioned. Also blood glucose was a random sample or fasting sample also not given.
Option C & D ruled out as in latent Diabetes & in Impaired Glucose tolerance, blood
glucose level is high, but not up to diabetic level(fasting and Post prandial)
Then thinking of other options Galactosemia & Fructosemia
Both cases give urine benedict’s test positive.
Blood glucose Oxidase test is specific for glucose ,here its normal.
Considering HFI & Galactosemia ,both have fasting hypoglycemia,but in fed state blood
glucose is normal.In the question it’s not mentioned fasting ,hence consider it as a random
sample.So both Galactosemia and HFI are possible.
First we think about d/o associated with Fructose metabolism
1.Essential Fructosuria 2. HFI
Among these two Essential fructosuria is the better option than HFI ,as HFI it is a toxic
condition,the question should give age of the patient and associated features.Where as
Essential Fructosuria is a benign condition with normal blood glucose and Urine red sugar
+.But here option is NOT GIVEN as FRUCTOSURIA but FRUCTOSEMIA.The correct
term is Essential Fructosuria according to standard books not FRUCTOSEMIA,even
though blood fructose will be high.
Below OMIM title of Essential Fructosuria is given.