Recognizing Highs, Lows & Emergencies
What to watch for, and when to get help.
Once you’re living with diabetes, blood sugar can swing in either direction. Most of the time it’s manageable โ but a few situations need fast action. Here’s how to spot them.
When blood sugar runs high
Hyperglycemia happens when there isn’t enough insulin to move glucose into your cells.
It can build up slowly over hours or days, and many people start noticing symptoms above 250 mg/dL. If it goes unchecked for too long, it can become serious.
๐ What you might feel
- Very thirsty
- Needing to pee a lot
- Feeling weak or tired
- Headaches
- Sometimes nausea
โ ๏ธ Signs that need urgent care
- Sudden change in vision (blurry vision)
- Fruity- or nail-polish-smelling breath
- Deep, fast breathing
- Stomach pain, nausea, or vomiting
- Confusion or extreme drowsiness
- Very high blood sugar with ketones present
A note on vision: blurry or changed vision can show up with milder highs too โ but a sudden change is one of those things to take seriously. If it comes on quickly or feels different, treat it as a reason to get help.
DKA (diabetic ketoacidosis) is more common in type 1. HHS (hyperosmolar hyperglycemic state) is more often seen in type 2 diabetes, with very high glucose and severe dehydration. It’s less common than DKA in teens but can happen โ especially during illness.
Note: symptoms aren’t always reliable. Some people don’t feel mild or even moderate highs โ especially if they’ve had diabetes for a while. Your meter or CGM is the best way to know.
When blood sugar runs low
Hypoglycemia means blood sugar has dropped below 70 mg/dL โ this is when you should treat it.
Lows can come on within minutes โ and unlike a high, they usually need to be treated right away.
๐ Early signs
- Shakiness or trembling
- Sweating or chills
- Sudden hunger
- Fast heartbeat
- Dizziness or lightheadedness
- Headache, trouble focusing
- Mood changes (anxious or irritable)
- Pale skin, tingling in lips or tongue
โ ๏ธ Signs that need urgent help
- Blurred or double vision
- Slurred speech
- Poor coordination, clumsiness
- Confusion
- Seizures
- Loss of consciousness
๐ Lows can also happen at night
- Restless sleep
- Sweaty clothes or sheets
- Crying out during sleep or nightmares
- Tiredness or confusion when you wake up
โ ๏ธ A heads-up: hypoglycemia unawareness
If you’ve had lots of lows recently, your body can stop giving you the early warning signs. This is called hypoglycemia unawareness, and it’s potentially dangerous because a low can become severe before you notice anything’s wrong. Tell your medical team if you notice this happening โ they can help you get the warning signs back.
When to contact your medical team
๐ Call your diabetes team right away ifโฆ
- You see severe signs of a high or a low (any of the “severe” cards above).
- You see milder signs but you’re not sure how to treat them safely.
- A high or a low isn’t responding to what you’d usually do.
It’s always okay to ask. Your team would rather hear from you early than late.
If someone passes out or has a seizure
๐จ What to do
- Call 911 (or your local emergency number) right away.
- Do not give food or drink to someone who is unconscious, having a seizure, or unable to swallow safely. They can choke or aspirate.
- Give glucagon if available โ if you know the person has diabetes and a glucagon kit is nearby. Don’t wait for the ambulance to arrive; every minute counts.
- Stay with them until help arrives โ turn them on their side (recovery position) if they’re unconscious or having a seizure, to keep their airway clear.
โก๏ธ What’s next
This chapter is about recognizing highs, lows, and emergencies. For the day-to-day “how do I treat a low?” or “how do I bring a high down?” steps, head to Managing Highs & Lows โ How to Treat Blood Sugar Complications.
TeenHealthInsight is a health education website โ not a substitute for medical advice. Any questions or worries about your medication, devices, or daily care should be brought to your doctor. Learn here, decide there โ always loop in your diabetes team before changing anything you do.