Unexplained consistent night-time hypos

[PJR76]

I'm a type 1 diabetic on humalog, tresiba and prolonged release metformin.

Going through a period of self-diagnosed altered insulin sensitivity.

For the past few weeks I've had pretty consistently, very sharp and unexplained night-time hypos.

Very sharp equates to a warning at c. 5 mmol/L, then 10 minutes later after hypo treatment glucose dropping to c. 2 mmol/L.

I believe that my basal dose is accurate and stable, tested multiple times.

I have been up until fairly recently on high insulin to carbohydrate ratios, these were:

Breakfast 2.75u / 10g
Lunch 1.5u / 10g
Dinner 1.75u / 10g

These ratios up until fairly recently have been stable.

The sudden unexplained propensity for hypos has increased, so I have taken it upon myself to reduce my ratios. My current ratios are:

Breakfast 2.25u / 10g
Lunch 1.5u / 10g
Dinner 1.25u / 10g

Tresiba (Basal) 26u

I must admit I do find my insulin sensitivity very volatile and complicated to manage, but must biggest concern is the unexplained sudden night-time hypos.

My hospital diabetologist is not very helpful and I'm more knowledgeable than the GPs with diabetes at my practice.

Any ideas and suggestions kindly appreciated.

Many thanks,

Philip

 

[EllieM]

Have you lost or gained any weight to alter your insulin sensitivity? Or changed the amount of exercise you take? Or reduced your overall carb intake?

As for the sudden night time drop.... I know I'm clutching at straws, but have you backed the reading up with a bg monitor? I've noticed that my dexcom sometimes exaggerates my hypos. If it was just a gradual drop, I'd say reduce your basal, but that sudden blip is weird.

How recent is your diabetes? Is there any chance you are still in a honeymoon period and producing some insulin?

Finally, and another long shot. What are your injection sites like? Any chance you've overused a site and it's leading to uneven absorption of insulin? (Not totally sure whether that's even a thing.)

Good luck. Hopefully someone else will come up with some better suggestions....

 

[PJR76]

Have you lost or gained any weight to alter your insulin sensitivity? Or changed the amount of exercise you take? Or reduced your overall carb intake?

As for the sudden night time drop.... I know I'm clutching at straws, but have you backed the reading up with a bg monitor? I've noticed that my dexcom sometimes exaggerates my hypos. If it was just a gradual drop, I'd say reduce your basal, but that sudden blip is weird.

How recent is your diabetes? Is there any chance you are still in a honeymoon period and producing some insulin?

Finally, and another long shot. What are your injection sites like? Any chance you've overused a site and it's leading to uneven absorption of insulin? (Not totally sure whether that's even a thing.)

Good luck. Hopefully someone else will come up with some better suggestions....

Thanks for your questions.

I have recently lost some weight and have reduced my carbohydrate intake. This would most likely account for the reduction in the ratios.

I've had diabetes since 1994, so approx 26 years. Most definitely not in the honeymoon period!

Exercise is generally problematic as virtually anything sends me crashing pretty quickly. Just walking for 10 minutes can have a dramatic effect.

I try to rotate my injection sites as best I can. I don't believe I have any lipodystrophy or if there is any, it's minimal.

 

[PJR76]

Have you lost or gained any weight to alter your insulin sensitivity? Or changed the amount of exercise you take? Or reduced your overall carb intake?

As for the sudden night time drop.... I know I'm clutching at straws, but have you backed the reading up with a bg monitor? I've noticed that my dexcom sometimes exaggerates my hypos. If it was just a gradual drop, I'd say reduce your basal, but that sudden blip is weird.

How recent is your diabetes? Is there any chance you are still in a honeymoon period and producing some insulin?

Finally, and another long shot. What are your injection sites like? Any chance you've overused a site and it's leading to uneven absorption of insulin? (Not totally sure whether that's even a thing.)

Good luck. Hopefully someone else will come up with some better suggestions....

Sorry forgot to mention that the Dexcom reading was corroborated with a finger prick test. I also rang 111 and had a lengthy conversation about it with an on call GP.

I'm hypo unaware and don't really feel symptoms until the glucose level is below 3 mmol/L. Hypos tend to happen very quickly.

 

[EllieM]

Exercise is generally problematic as virtually anything sends me crashing pretty quickly. Just walking for 10 minutes can have a dramatic effect.

Sounds like you might be a good candidate for an insulin pump?

 

[EllieM]

prolonged release metformin.

Is it possible that the metformin is an issue, given that it inhibits sugar production by the liver?

 

[PJR76]

Is it possible that the metformin is an issue, given that it inhibits sugar production by the liver?

I was put on the metformin because my ratios were getting ridiculously high and I believe I was suffering with absorption issues.

I suppose back then I was eating high quantities of carbohydrate in my meals, which would also account for high bolus dosages. I was easily injecting over 50 units, sometimes up to 80 units of insulin. My DSN couldn't comprehend the dosages.

I feel happy on the Metformin for the time being, unless you know something I don't.

 

[EllieM]

My DSN couldn't comprehend the dosages.

Got any T2 members in your family? (I have similar high ratios of insulin to carbs and my dad is T2).

I feel happy on the Metformin for the time being, unless you know something I don't.

No, I was just considering all the possibilities.

I do wonder how common unusual dips like yours are at night, though. Most people would sleep through them if their livers rescued them and wouldn't know if they didn't have a cgm.....

 

[PJR76]

Sorry to read about your problems.
I only have one thing to add to the comments from @EllieM - you mention that your blood sugars fall after you take your hypo treatment. Has this been corroborated with finger pricks? As CGMs are, typically, 15 minutes behind your true readings and less accurate when low, the time in hypo after noticing is exaggerated on a CGM.

Ok, I said one thing, but I meant two!
You say you believe your basal is correct because you have tested a few times. When was the last time you tested? It can (and does) change so it could be worthwhile checking it again. And, remember, if you change your basal, Tresiba takes 3 or 4 days for the change to take effect.

Yes, it's quite common (according to the G6) for my blood glucose to continue to fall after taking hypo treatments.

I have when symptoms become quite severe (i.e. glucose levels affecting brain and cardio function), over compensated on hypo treatment. I know you're not supposed to do that, but sometimes my hypos can linger on for 1.5 to 2 hours with very little upward trend in the direction of blood glucose slope.

Other times, I take treatment, it will rise a little bit, then backtrack and start to fall again.

I sometimes require 80g to 100g of quick-acting, high GI, glucose based hypo treatments (i.e. glucose tablets, lucozade et al.), with a more starchy carbohydrate (i.e. cake, biscuits, sandwich) and still the blood glucose levels were resisting the attempts to circumvent the remedy.

I remember on one occasion I went out for a walk and had consumed in excess of 200g CHO in various forms of GI and my blood sugar didn't climb above c. 8 mmol/L.

There seriously appears to be no specific variable that I can attribute to this strange phenomenon and to be brutally honest with you, it scares me (at appropriate expletive here).

Other occasions I obviously do have rebound highs due to over compensating.

I realise that everybody's individual metabolism and absorption of hormones and sugars is different, but my results are just weird.

I do believe that my Tresiba dose is correct, there is no way in any circumstance that a slightly inaccurate basal dose would cause such a sharp decline in slope (to the best of my knowledge). I'm also unsure if there is any documented evidence to suggest that insulin sensitivity is dramatically affected during the small hours.

I do sometimes wake up in the morning outside of range, with an unexplained high, following a steady overnight trail of hovering around 5.5 mmol/L. This I believe is the Dawn Phenomenon, which of course is currently impossible to accurately predict or treat.

I apologise for this highly technical appraisal, but sometimes you have to be technical to get your point across and unfortunately GPs just don't understand, hence why I have to come to a specialist forum for advice.

Any advice/assistance greatfully appreciated.

Best regards,

Philip

 

[Catman507]

Could be a basal issue maybe, i also suffer from nocturnal hypoglycaemia involving my partner panicking because I am non coherent and shallow breathing, woken by paramedics many times. Do you take your basal before bed? I am not a doctor so I wouldn't take my advice 100% and would speak to somebody first but I was told to take my basal in the morning instead or split the dose in two! Morning and night. If you take in the morning, it should be at its peak for lunchtime if you consume lunch or breakfast and will be slower at the nighttime when you sleep when you are not eating food. This is what was recommended to me.

 

[PJR76]

Hi Catman507, thank you very much for your response.

I'm unsure if it is a basal issue or not to be honest. In recent weeks, it is the only variable that I haven't touched. I did telephone my DSN, and she suggested that I reduce my Tresiba from 26 to 25. I tried to refute her suggestion on the basis that the Tresiba shouldn't in itself cause a dramatic down spike in the early hours of the morning. Even so, I relented and have agreed to reduce it and see what happens.

I take my basal generally around 9 pm; it can be later if I forget or do not act upon it straight away. One of the benefits of being on Tresiba is that it isn't as time-critical in comparison with other basal insulins.

My understanding also, is that analogue insulins such as Lantus and Tresiba do not theoretically have a peak. They were designed as such to try and minimise the chances of going hypoglycaemic during the night.

Here is a chart with the insulin profiles mapped out:

https://www.diabetes.org.uk/resourc...20of%20Leicester%20-%20Insulin%20Profiles.pdf

 

[EllieM]

FWIW, (probably not very much), the last time I saw my clinic for adjusting my bolus (this was pre dexcom so I didn't have a way to check my night time levels and they gave me a cgm for a week), I ended up reducing my basal significantly, even though I'd been edging it up so as to combat dawn phenomena.

Not sure how long it takes glucose to be absorbed into the bloodstream, but google say 5 to 15 minutes, so that, combined with any cgm delay (dexcom support say 15 minutes but may sales rep reckons more like 1 minute, so I guess that varies from person to person) probably accounts for the delay in your levels going up when you treat the hypo.

From personal experience, I would expect your basal needs to go down significantly if you've lowered your carbs and/or lost weight.

I realise that everybody's individual metabolism and absorption of hormones and sugars is different, but my results are just weird.

Just trying to cover all the bases here, has anyone ever considered that you might be MODY instead of T1??? (Seems extremely unlikely, given the quantity of insulin you need, but MODY qualifies as weird.)

Going on a pump would have the advantage that you could experiment with lower basal rates at night and just suspend your basal if you go hypo. I would have thought you'd qualify for NHS funding, given your issues with hypos. (Like you, my hypo awareness is not as good as it used to be, and I'm dreading going back to fingerpricking if/when I become allergic to the dexcom. Hypos are perhaps the worst part of T1 diabetes.)

Good luck.

 

[Daibell]

HI. How many carbs roughly do you have each day?

 

[PJR76]

It varies quite considerably.

A couple of hundred perhaps.

 

[Fairygodmother]

Maybe you need to take all these questions to a Diabetes Consultant? You’ve a number of different parameters to deal with: weight loss, carb intake, metformin etc and the way they interact and affect your levels may or may not need tweaking. I really sympathise with the worry and sleep loss of night time hypos!