I hope someone can shed some light on a problem we're having. Out 11yo daughter (dx T1 17mth) has a Veo pump (Revel in US?) and Enlite CGMS for which we are very grateful. However, the CGM tells us that most nights she has very sudden, severe hypos followed by what we presume to be liver dumps resulting in his BGs come morning. Without the CGM we would most likely not be aware of these as she is hypo-unaware though the higher morning readings would suggest something is up at night.
She could be on a glucose level of 10mmol/l (180mg/dl) and within 10-15 minutes her CGM shows <2.2 mmol/l (38mg/dl) followed by an equally quick rise to perhaps 11mmol/l (198mg/dl) or more. We've tried everything we can think of.
We've given her a supper of full fat milk & occasionally some cheese, sometimes with very low bolus to cover. We've dropped her basal from 10pm until 3am by more than 60% of that leading up to 10pm. We've monitored exercise to see if it was being caused by PEL (post-exercise late onset hypo) but it happens even when she's had no exercise for days.
Usually it happens between 12:30 and perhaps 2am but more recently it's happened at 11:30 or 4:30. We've on occasion by luck 'caught' it by BG but the number we get is likely later than the actual event given the CGM is 10-15 behind so the BG shows something like 7.0. However, this continues to rise (Symogyi effect) as we prove with later BG tests.
From my reading I'm beginning to think it might be thyroid related though her last bloods were clear. She does have celiacs already. Any help much appreciated,
Am not an expert here. Sounds very worrying. Have you tried giving her a fat and protein snack (slowly digesting) before bed... I would think that the milk would digest too quickly to affect her much 5 or 6 hours later....
Maybe someone else can suggest.
thanks for reply. Yes, we've given 200ml full fat milk as well as some cheese before bed, sometimes fully covered by insulin and other times with reduced insulin. However, she still drops rapidly seemingly regardless of how high she is.
As I say, we're out of ideas on this and worried,
What about trying meat, or nuts? Am trying to think of something that will digest more slowly / last longer.
does she have this every night? can you see anything done differently on the odd occassion she doesn't have it, or when it is less extreme?
Are you using a meter to confirm these numbers or is this SG. It's hard to believe her
BG is dropping 140 mg/dL in ten minutes while sleeping (no activity). You need to test
her with a meter every couple of hours for a few nights and get some good BG data.
Anytime her pump gives a low/high prediction you should do a meter test.
I have had many SG readings that drop 100 points in a few minutes but this happens
because the sensor is dieing. I also have sensors that fall out of calibration when
I'm not active, the Isig: just drops low or it flat-lines. This can also happen when
I stay in one position for a couple of hours.
You need to test, test, test....
you're right to be cautious of CGM readings but the Enlite when properly calibrated is very accurate though naturally there's a 10-15min delay given that the reading is from the interstitial fluids. We have on occasion been 'lucky' enough to catch the low but it's typically already on the increase thanks to the counter-regulatory response of the liver. We do know from BG testing that the drop and rise does happen well within a 1 hour duration. Coupling that with the very reliable results of the CGM on 90% of occasions and the rep confirming that it was likely accurate, we're pretty confident (having rejected the possibility previously) that this is happening as described.
But your mention of the Isig: when I dug out the logs one evening I saw that the ISig did drop a lot as the 'low' began. I'm not sure of what the ISig reflects (signal strength or confidence?) but there is a correllation. Any other info would be useful.
Thanks to all responding - I'd really like to figure this out ahead of our endo appt. in 2 wks.
Also, she's on .5U/hr basal from 5pm to 10pm and then dropping to .3 until 3am - that's our latest effort to head off the events.
I have no experience w/ the Enlite as we don't have it in primitive countries like the USA.
If she's trying protein/ fat and it's not covering the low, maybe something a bit more substantive? I've sort of had similar problems lately, we've had a bunch of really late dinners repeatedly so I have like 3U on board @ bedtime and I'm like "I don't want to go high but I don't want to go low and I'm SLEEPY!!" so I sort of fumble through it and have had a bunch of crappy results.
It might also be useful to try to eat dinner earlier, to "clear the decks" and get the stray "tail" of the dinner bolus out of the way before bedtime?
Some things strike me as odd in your description of the events.
A fluctuation of 180 mg/dl to 38 mg/dl within 10 minutes is possible. However these are rare events with much insulin on board or result of a high metabolic rate. Like John I have my doubts about the accuracy of CGMS in general - especially in the short timeframe of 10 minutes. The way you describe it she experiences the drop even with little insulin on board. The question remains how the 142 mg/dl of blood glucose could disappear within 10 minutes. Celiacs can lead to a permanent inflammation of the intestine. In a severe and untreated case this can lead to the malabsorbtion of nutrient, amino acids and vitamins. Do you think the insulin is overtaking the absorbtion of the glucose in the first minutes? I doubt that insulin can act that fast with the passage through the skin but still it is one possibility to rule out. Have you tried different analog insulins like NovoLog, HumaLog or Apidra? Perhaps she is just showing some strange reaction to the insulin or the preservatives used. Even regular insulin can be worth a try - at least it can not cause quick lows. This may lead to much trial and error but it will be worth the effords.
The Symogyi effect is often mentioned but there is little scientific evidence about its existence. The biggest problem is that the Symogi effect is claimed to be a result of counter regulation. But counter regulation can only happen if there is no active insulin present. This is why most insulin dependent diabetics will not experience this effect at all. For us the counter regulation is broken because insulin is always present. In contrast some members have experienced the release of glucose due to emotional events like stress or falling in love. So there is some sort of hormonal and emotional component involved and according to the age of your daughter this might be something to consider too.
thanks for such an indepth answer. It's good to get others perspective on this. First off, nearly always when we 'see' this drop, she has no insulin - last bolus would typically be 5-6 hours previous. She's using Novorapid (Humalog?) only in her pump and we see a period of activity of about 4 hours.
Her nurse commented yesterday that .6U/hr basal from 6pm to 10pm might have a run-on effect through to 1am and she felt that level a bit high for her age. However, we established that a couple months ago along with other basal settings/carb ratios and felt it necessary then. Of course, we're gearing up now for another round of fasting basal testing - tricky with a 11yo!
I've read about hypothyroidism and adrenal suppression issues that can manifest with the hypos we have but I'm trying to identify the more common likely culprits first before 'taking on' another illness.
I'm pretty confident her celiac is well controlled. We'll ask for another test at next appt. but we try really hard to food and cook everything ourselves carefully. I even have a blog on our recipes! (sligosweetspot.blogspot.com).
But (finally) I am convinced there is a hypo but you're right to be suspect about the rapid nature of it. However, we have proof (BG) that she is stable until we last check her around 12am and the CGM shows she would have been even to that point too and by then with very little insulin on board (apart from the basal). And we are sure that she comes in high in the morning consistent with the CGM reading then. So either the CGM is totally (and consistently) wrong and that perhaps she has too little basal to cover the dawn phenomenon (resulting in high morning readings) or she does go low early in the night and we're witnessing a liver dump effect come morning. Frankly, I'd prefer either of those scenarios to the sudden rapid drop that the CGM shows us!
Thanks again and your ideas most welcome,
I haven't ever done fasting basal testing to set rates. If I run low like 3 days in a row before a meal, sort of the scenario you are describing, although sometimes a late dinner, can linger on into the evening too, I'll lower the basal for the chunk of time in question. I have different rates for 1:00 AM-3:00 and then a higher one from 3:00 AM until 7:00 AM and that seems to have smoothed things out although they still change periodically?
I agree with Holger that the Symogyi effect which is often talked about is rare. However, the effect does happen when someone has a harsh low, even with some insulin on board (like a basal) you will counterregulate and that rebound high is the Symogyi effect.
I would also like emphasize Holgers last suggestion. There are conditions that can cause hypo problems. In particular adrenal issues can cause blood sugar regulation problems, and there are autoimmune conditions that may be involved. Your daughter should be tested for this. Also, if your daughter suffered high blood sugars she might have some kidney impairment. If your kidneys don't work properly, it can cause insulin to accumulate and cause hypos. There are also some medications that can cause hypos.
I'm sorry to hear you are still having problems. It sounds like the snack before bedtime did not work. Although you might think that a lack of specific exercise rules out PEL, your daughter may just be active enough during the day that it really doesn't matter.
It might be worth trying a more aggressive "meal" in the evening. I might suggest a "carb load." Perhaps 50 grams of fast acting carbs. Bolus enough to enable the uptake of the glucose, but not enough that you are nervous about insulin on board. Perhaps eat at 8pm and then most of the insulin will have worn off before you hit the time of concern. This may "prefeed" a low and avert it.
And finally, I would suggest that you are probably at the limits of how we can help you. I would enourage you to reach out wider. Read up on the literature on hypos in children, on PEL, etc. I can provide some pointers. And I think you can send some emails to medical experts and see if they have suggestions. I will msg you some contacts.
Hi jake42, I share your frustration as I've been experiencing similar drops at night myself. Of course, I'm a 51 year old female so not exactly the same situation, but in the last month I started dropping anywhere from 40 to 140 points between midnight and 3 a.m. then it would go back up. Sometimes it would be a shorter faster fall and recover but always between midnight and 3.
I know that this is happening and not just a fluke of the cgm because I went to bed high one night at 190 and woke up at 1:30 a.m. at 50 when my Dexcom alerted me. Confirmed it with a fingerstick.
My endo said that with these types of drops only at night typically what comes to mind is kidneys. My endo redid my labs to check kidney and liver function and ruled out problems there. I'm still waiting for thyroid results.
We have been gradually adjusting my basal down (I'm still on MDI so don't have the flexibility of the pump). I've been basal testing but making sure I start high enough to avert a low and then looking at starting and ending numbers each day along with my Dexcom graphs to see the trend and time.
I've been reading extensively and what I find echoes what Holger and Bsc said. Major stress (my husband was laid off), hormones (pre-menopause for me), medication (currently on antibiotic known to affect bg). I also read about adrenal issues but my endo didn't want to explore that option at this time, not sure why, maybe because it only happens during a 3 hour window.