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Troubleshooting: Hypo and Hyperglycemia

This article reviews causes of hypo and hyperglycemia and briefly highlights possible solutions for patients on insulin pump therapy. 

Causes of Hypo / Hyperglycemia Not Specific to Insulin Pump


For a visual "lay person" colourful blog post see here

HypoHyperPossible Solutions
Psychosocial considerations x x Consider asking "What's the hardest part about taking insulin?" or "How do you feel..." e.g. about new doses, giving insulin in general, etc. 
Insulin storage or expiry   x  
Missed doses. Also consider diabulimia.    x  
Incorrect dosing - unintentional or intentional.  x x  
Incorrect target (mmol/L) or incorrect use of formula.  x x  
When bolus is taken (adequate, too much ac or pc) x x  
Dose needs adjusting secondary unknown changes in diabetes.  x x  
Exercise changes x x Temp basal if on pump
Incorrect carb counting x x  

Diet Changes

Glycemic Index

Protein & fat intake. 

Low Carb or Ketogenic Diet 

x x
  • Query if patient would change diabetes meds/doses or food portions.
  • Query appetite, possibility of gastroparesis. Note in the case secondary diabetes requiring insulin due to total pancreatectomy the patient may be at greater risk of severe hypoglycemia. (They may also present with GI symptoms similar to gastroparesis which suggests they may need adjustments to enzyme replacments. Alert endo to address this. Refer to RD.) 
  • Try temp basal; dual/square bolus if on pump.
  • Some people with type 1 diabetes may benefit from working with their healthcare team to try different algorithms for giving insuiln for protein and/or fat
  • If low carb or ketogenic diet, query treatments for hypoglycemia. If no or ineffective treatment, with the patient's permission, review rationale for using fast carbs noting that untreated hypo may increase risk of hypo unawareness which could impact driving. Encourage a referal to RD so the patient may continue their desired diet safety. 
Menstrual cycle x x Alternate basal profile; temp basal if on pump
Puberty   x  
Weight changes x x  
Gastroparesis x x Dual/square bolus; temp basal if on pump
Drug/drug interactions x x  See summary of drug interactions and Drug Product Database
Exercise injection/infusion site x   Temp ↓basal if on pump
“Virgin” sites x   Temp ↓basal if on pump
x x Rotate injection/infusion sites for more reliable insulin absorption.
Intramuscular injection x   Review pinch method and injection sites if very lean
Stacking corrections x   Correct to 8-10 mmol 2 hr pc or read pump calculations
Pregnancy (early) x    
Pregnancy (late)   x For pump: Daily set changes. Active insulin time in pump may need to be reduced to 3 hr.  
Breastfeeding (as well as possible mastitis) x x (Potenital lows with breastfeeding. Potential highs if mastitis)
Alcohol x    
Adrenal insufficiency x    
Renal disease x    
Bariatric surgery x   Post-bariatric hypoglycemia can occur typically 1-2 hours pc meals even in those not on insulin or secretatogues. This may occur up to few years after surgery. Refer to an RD to discuss management. 
Pen not working or used incorrectly.   x Syringe for corrections with ketones!
Spoiled insulin with heat (summer)   x

During heat waves:

  • Keep current vial of insulin in the fridge
  • Try not to spend extended hours exposed directly to sun e.g. sunbathing (for overall health and for insulin in pump). Use an umbrella if laying on beach.
  • Consider smaller “fills” e.g. replacing pods (or reservoirs if other pumps) sooner than 3 days.
  • Never store safety kit in the car, where can overheat the “safety” insulin quickly
  • Can get a small Frio pack to keep a pen vial of insulin cool in a safety kit if on a beach.
Illness/stress/silent MI (x) x Temp basal if on pump if appropriate. Occasionally a person responds to stress with hypo. 
Medication Changes  x x Check with pharmacisty regarding any drug-drug interactions if blood sugars changed after starting new medications.
Hydroxyurea     x Hydroxyurea can falsely elevate sensor glucose readings in Medtronic and Dexcom sensors (2021). Not Libre. Hydroxyurea is found in some drugs to treat some cancers, sickle cell anemia and other conditions. It is found in Hydrea™, Apo-Hydroxyurea™, Mylan-Hydroxyurea™* and hydroxycarbamide.



Increase insulin or addition of insulin to address peak rise of glucose values; Increase temp basal if on pump;

Inaccurate glucose meter or sensor x x Refer to product user manuals

Insulin Pump Programming

SituationsHypoHyperPossible Pump Solutions
Earlier temp basal used x x  
Earlier square wave/extended bolus used x x Normal bolus may have been needed or % normal/extended needs changing
Mixing up a.m. and p.m. when programming. x x  
Basal rate mistakenly changed. x x  
Time on clock wrong from travel or daylight savings time x x Sign up for Pump Pointers as reminders are sent when daylight savings time changes.
Active insulin time too short X   Standard time is 4 hours. See note below.
Active insulin time too long   X Standard time is 4 hours. Active insulin time may be shortened in occasional situations eg. 3 hours in the third trimester of pregnancy e.g. in those who are confident their basal is set but at 3 hr pc when in target, their IOB indicates they would drop further, but they don't. e.g. at 3 hr pc BG occasionally elevated, pump advises no correction as IOB, but patient remains at the same BG level by 4 hr pc.
Targets programmed into pump (specifically low end) Omnipod information clarified with Omnipod IT via phone 2017   x IF BLOOD GLUCOSE UNDER TARGET: Animas will make two subtractions from meal bolus. One as a reverse correction to keep person in target and the second to subtract ALL the insulin on board. This may lead to severe under insulinization at times. To avoid, consider setting target of 4-7 which would read 5.5 +/- 1.5 if appropriate. Then it will subtract all IOB if under 4 mmol. Omnipod will subtract using a reverse correction (if turned on) and will always subtract previous insulin given for correction regardless if reverse correction is turned on. It will not subtract previous insulin (IOB) given for meal bolus. Omnipod distinguishes between IOB from correction or meal bolus. Medtronic will subtract using a reverse correction. No IOB is subtracted from meal bolus.
Max bolus reached and second "make-up" bolus not delivered.   x Reprogram for bigger max bolus (max possible is 30 units for Omnipod)
Suspend is on   x Omnipod requires pump be suspended before making basal changes, and resumed after.

Cannula and Infusion Site

SituationsHypoHyperPossible Pump Solutions
Insertion close to muscle mass x   Temp ↓basal; Change site; Use angled infusion sets manually adjusted for muscular areas as can insert shallower
Intramuscular insertion x   Change site
Cannula left in too long   x Change q 2-3 days (q 1 for third trimester or q1-2 for large TDD). If infusion sites are hard to reach query frequency of set changes (eg. shoulder, back love handles, buttocks). If on Apidra insulin, change reservoir and set every 2 days. Metal cannulas change q 1-2 days.
Kinked cannula   x Try angled set (manually adjust angle) so not bumping muscle mass; try metal cannula; try different insertion method (device or manual); change if notice pain after bumping
Tunneling (click for image in 30 degree set or here for Omnipod)   x
Change set/pod when notice wet material (see left to click for images). Look for tunneling often, especially if corrections aren't working as well as anticipated. It can occur with movement, sleeping on pod/set, large boluses. Try:
  • Extended boluses or slower insulin delivery
  • Changing set or pod more freqently
  • Different infusion sites with less movement
  • Try taping to reduce movement (e.g. Tegaderm)
Too shallow insertion near skin surface so “bumps” out with bolus   x Assess sites; instruct on angle of insertion 20-45 degree for angled sets.
Unknowingly set ripped out   x Instruct on a safety loop; Pull tubing twice daily to ensure connections
Adhesive sweats off   x Try Skin-Tac product (buy from pump company, pharmacy or Blain MacLean Pharmacy & Surgical supplies); unscented hypoallergenic antiperspirant; tape/dressing like Tegaderm or IV3000.
Site irritation/tape irritation may impact insulin absorption secondary inflammation.   x Use new site; Try Skin-Tac liquid or wipes on skin first; Tegaderm or IV 300 on skin first with hole cut for cannula; choose sites carefully to avoid those by pant line, bra/underwire.
Cannula not inserted as needle guard not removed using a set with a serter.   x  

Reservoir and Infusion Set Tubing

SituationsHypoHyperPossible Pump Solutions
Priming tubing issues (primed when connected to body or forgot prime) x x Read screen instructions when filling/priming.
“Fill cannula” amount is set incorrectly or cannulas not filled x x  
Tubing not fully connected to cannula at the site.   x Pull tubing twice daily to ensure connections
Leaking at hub/connection   x Review tightening; be sure dry when connect
Bubbles in reservoir/tubing   x Use room temp insulin; prime tubing with reservoir held vertically (top facing ceiling); prime tubing until visible bubbles are out of tubing; change reservoir earlier if noticed many champagne bubbles when filling – they can “clump” to make big bubble when close to empty reservoir; do not disconnect tubing from reservoir until set is changed
Occlusion or other no delivery alarm   x When filling reservoir, lubricate it by pulling plunger up and down a few times prior to filling with insulin; load reservoir vertically especially if not using full reservoirs
Tubing/reservoir re-used too many times, or on Apidra.   x Use new reservoir and tubing each set change. If on Apidra insulin, change reservoir and set/tubing every 2 days.

Physical or Mechanical Insulin Pump Problems

SituationsHypoHyperPossible Pump Solutions
Casing cracked and water inside; insulin leaked inside x x Advise no exposure to water if cracked casing. Advise when remove pump for medical procedures arrange pump so that insulin being delivered is not being directed into/onto the pump (eg. if in baggie may need "zero" temp basal)
Pump dies, screen fails, pump buttons stop working   x Call 1-800#. Often replaced within hours. Review “Coming off pump” handout with client to prevent DKA. Http://
Magnet at theme park ride affect pump function x x unknown if pump function would result in highs or lows.
Pressure changes with roller coaster or scuba diving affect pump function x x unknown if pump function would result in highs or lows. Expect lows moreso with g-forces forcing insluin out potentially
Liquid gets on the top of the reservoir or inside the tubing connector when connecting the tubing to the reservoir x x This is for Medtronic: Liquid can temporarily block the vents. This may result in the delivery of too little or too much insulin.