Differential Diagnosis for High Glucose in Urine but Normal Serum Glucose
Single Most Likely Diagnosis
- Renal Glycosuria: A benign condition where the kidneys excrete glucose into the urine even when serum glucose levels are normal, due to a low renal threshold for glucose reabsorption. This condition is often asymptomatic and discovered incidentally.
Other Likely Diagnoses
- Pregnancy: During pregnancy, the renal threshold for glucose can decrease, leading to glycosuria (glucose in the urine) even with normal serum glucose levels. This is due to increased glomerular filtration rate and changes in renal tubular function.
- Medications: Certain medications, such as carbonic anhydrase inhibitors, can increase glucose excretion in the urine without affecting serum glucose levels.
Do Not Miss Diagnoses
- Diabetic Nephropathy with Early Kidney Damage: Although serum glucose might be normal at the time of testing, early kidney damage from diabetes can lead to glycosuria. It's crucial to assess for other signs of diabetes or kidney damage.
- Fanconi Syndrome: A rare disorder of the proximal renal tubules where glucose, amino acids, and other substances are excessively excreted in the urine. It can be a sign of an underlying serious condition.
Rare Diagnoses
- Glucose-Galactose Malabsorption: A rare genetic disorder affecting the absorption of glucose and galactose in the intestine, which can lead to glycosuria.
- Cystinosis: A lysosomal storage disease that can cause renal tubular dysfunction, including glycosuria, among other systemic manifestations.
- Wilson's Disease: A genetic disorder leading to copper accumulation in the body, which can cause liver disease, neurological symptoms, and occasionally renal tubular dysfunction resulting in glycosuria.