December 24, 2002
Diagnosis and Symptoms
Question from London, England:
I have had well controlled type 1 diabetes for 25 years, and even though my three year old son is showing none of the classic symptoms of diabetes (except sometimes he is a little more thirsty than others), he has 3+ glucose in his urine, but blood glucose monitoring levels are normal. What else could be the cause of glycosuria in such a young child if not diabetes? Can diabetes be present but not picked up yet? He. Urinalysis was done by myself and our general practitioner and blood tests done by hospital. We are going for further tests today as they think he may have some iron deficiency. Would this have any connection?
Answer:
The so-called renal threshold is normally around 10 mmol/L [180 mg/dl] so there is no glucose in the urine unless the blood level has exceeded this threshold since the bladder was last emptied. The most common reason for glucose in the urine without a raised blood level is a low renal threshold which is usually entirely benign. There are a number of very rare conditions associated with leak of glucose into the urine, but these are associated with leak of other substances too, e.g., amino acids. These will be checked for.
KJR
