CGM Withdrawal Syndrome

Health Professional

It's sad that I have to admit this, but I had "CGM Withdrawal Syndrome" yesterday, last night, and this morning. As you may be aware, I've been using a continuous glucose monitoring (CGM) device for quite a few years (since 2010). I've written about the advantages of CGM several times; for example, see my discussion of the value of using CGM to help determine insulin pump settings: What Is Sensor-Assisted Pump Therapy?.

Obviously, I've grown to love the technology, but less obviously, I've actually become addicted to it.

What I didn't know, until my transmitter unit suddenly gave out, is that living without CGM can create a withdrawal syndrome, complete with anxiety, sleeplessness, and sudden urges to check meter glucose levels. I even found that I was carrying a meter with me on short automobile trips, like eight miles to the library and back.

Worse, when I check the meter's BG reading, I have no idea if my BG is rising, falling, or steady. For example, I got a 170 mg/dl reading about 2 hours after a meal: should I give more insulin (if the BG levels are rising), or no insulin (if the levels are falling dramatically), or a smidgeon of insulin (if the values are slowly falling)? And I lost the ability to glance at the CGM screen and see that I'm about to crash into a hypo episode, and hence couldn't avert disaster by suspending the pump's delivery and grabbing some calories. I crashed twice in the brief time I've been without CGM.

No wonder I was anxiousThe rest of the story: the transmitter gadget has an internal, non-replaceable, non-rechargeable battery (a terrible design flaw, in my opinion). The device is warranteed for only six months, and the battery typically dies somewhere between six and twelve months. I had been using my now-defunct transmitter for eight months. In the past, when I've been in a low-transmitter-battery situation, I would get a warning display, and be able to call Customer Service and still have a few days of battery life left. Therefore I never had a period of more than a few hours without my CGM. What I didn't realize is that sometimes the transmitter doesn't tell the receiver to warn you that you have a low-transmitter-battery situation. This time, when my transmitter's battery swooned, it didn't relay its death spiral to the transmitter — it just died a sudden death.

I made an urgent call to the 800 number, and the representative and I figured out what had happened, and she shipped me a replacement transmitter overnight.

FedEx delivered my replacement transmitter a bit over an hour ago. So I have about one hour more of withdrawal symptoms to tolerate, then I can get back to my addiction.

I can't wait.

Follow-up a few days later: My replacement transmitter's been working like a charm. I'm no longer anxious.

Some folks have asked about the ramifications of losing one's CGM capabilities. There are several points I can make for those of you using CGM, or if you are contemplating getting started:

  • First, the CGM's receiver has a hidden display where you can see the status of the transmitter. It's called "Transmitter battery" on my device, and mine currently says "OK".
  • Second, if you plan a trip outside the US, check with the manufacturer before leaving. My device's manufacturer ships only to the US (and to Puerto Rico, and maybe the other US territories) but not overseas. Their advice to me if going outside the US: (a) check expiry dates of devices before traveling, and order a replacement transmitter before leaving if it's soon to expire, and/or (b) talk to a friend or relative who'll be available in the States while you'r gone. If you have a failure, you could then have the replacement device overnighted to that person, who could then ship it overseas upon receipt.
  • Finally, you should always have ready access to standard BG meters. You should be checking your BG routinely to calibrate the CGM, but taking a meter with you is a safety measure if you're going to be away from home for more than a few moments.