This is an interesting case. Is he truly diabetic? Has the diagnosis of DM been confirmed by 2 fasting/random diabetic glucose results? He seems to be on a small dose of metformin 1 tablet daily (each tablet is 500 mg) which is unusual as the starting dose should be at least 500 mg twice daily.
This, of course, could be a case of DM developing in an individual with pre-existing renal glycosuria, has the nocturia developed/worsened recently?
 It may be useful to measure blood and urine glucose levels at hourly inetrvals over a period of time (e.g 6 hours), to determine at which blood glucos level, urine glucose becomes negative. Also measure urine volumes at the same time.
 
His nocturia may be aggravated by benign prostatic hypertrophy, although the presence of significant glycosuria may indicate that osmotic diuresis is the main drive. Does he drink too much fluid or feel thirsty at night? It is worth increasing his metformin dose and reducing his carbohydrate intake during the evening. I am not sure if renal glycosuria confers any protection from diabetic complications, as the main pathophysiology of T2DM is insulin resistance at cellular level.
 
Regards
 
Mohammad
 
Dr. M A Al-Jubouri, MB ChB, MSc, FRCP Edin, FRCPath
Consultant Chemical Pathologist


From: Rafaq Azad <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, 12 January, 2010 10:52:46
Subject: DM and renal glycosuria

A question for the diabetic experts:

We have a 62 year old type 2 DM patient who is well controlled with a 500mg/d dose of metformin (in divided doses).  His blood glucoses are never above 10 mmol/L and HbA1c is always <7.0%.    Whilst his diabetes is well controlled, he does suffer from debilitating nocturia, typically having to get up 6-8 times during the night.  This is obviously becoming a real nuisance for him.  His urine glucoses (measured on the night samples) are typically 30-40 mmol/L, even when his blood glucose is only between 7-8 mmol/L.  It is likely that he  also suffers from renal glycosuria and a lower renal threshold for glucose reabsorption.  This may confer him  some benefit in terms of cardiovascular disease and other long term complications of DM, but is proving to be a real issue as he is chronically sleep deprived.

The questions that have arisen is that how should such patients with dual pathologies be managed?

Should taking more of the metformin dose in the evening be beneficial?

Should he be advised to have a big meal late afternoon but only a small meal in the evening?

Any other suggestions would be most appreciated.

Regards,

Rafaq Azad
Clinical Biochemist.

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------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content. ACB Web Site http://www.acb.org.uk List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/