🤒 Sick Day Management for Diabetes: What to Do When You're Ill

A cold, a stomach bug, or a fever can be an inconvenience for anyone — but for someone with diabetes, illness can quickly become dangerous. The stress of infection triggers the release of hormones that raise blood sugar, even if you're eating less than usual. At the same time, vomiting or diarrhoea can lead to dehydration and hypoglycemia if you can't keep food down. Dr. Ravi Sishir Reddy explains how to create a personalised sick‑day plan, what to eat and drink, how to adjust medications, and the warning signs that mean it’s time to call your doctor or go to the hospital.

1. Why Blood Sugar Rises During Illness

When you are sick, your body releases a flood of stress hormones — cortisol, adrenaline, and glucagon — to fight the infection. These hormones tell the liver to release stored glucose and make your cells temporarily more insulin‑resistant. The result is that your blood sugar can rise significantly, even if you are eating very little. This is why stopping your diabetes medication during illness can be extremely dangerous — even if you think you don't need it because you're not eating, your body is still producing glucose, and without insulin or your oral medications, you can quickly spiral into hyperglycemia or diabetic ketoacidosis (DKA).

2. Your Sick‑Day Plan: What to Do in Advance

Dr. Reddy recommends every person with diabetes — especially those on insulin — should have a written sick‑day plan prepared with their doctor before they get sick. The plan should include:

• Contact information for your doctor and when to call.
• Instructions on how often to check blood sugar and ketones.
• Guidelines on adjusting your insulin or oral medications.
• A list of sick‑day foods and fluids to keep at home.
• When to go to the emergency room.

Store a printed copy of your sick‑day plan with your diabetes supplies so you don't have to think about it when you're feeling unwell.

3. Monitoring Blood Sugar and Ketones When Sick

• Check blood sugar more frequently: Every 2‑4 hours, even through the night if necessary. Illness can cause rapid changes in glucose.
• Check for ketones: If you have Type 1 diabetes, or if your blood sugar is above 250 mg/dL (even with Type 2), check urine or blood ketones every 4‑6 hours. The presence of moderate to large ketones is a warning sign that DKA may be developing.
• Record your readings: Keep a log of glucose, ketones, temperature, and medications taken. This information is invaluable if you need to speak to your doctor.

4. Should You Adjust Your Diabetes Medication?

Never stop your basal insulin (long‑acting) or your basal rate on a pump, even if you cannot eat. Your body still needs insulin to clear ketones and manage the glucose produced by the liver. In fact, your insulin requirements may increase during illness. Dr. Reddy provides general principles (these must be individualised by your doctor):

• Type 1 diabetes: Continue your basal insulin. You may need extra rapid‑acting insulin to correct high blood sugar and to cover the small amounts of carbohydrate in sick‑day foods. If ketones are moderate or large, you will need additional insulin and fluids — contact your doctor immediately.
• Type 2 diabetes on insulin: Continue your basal insulin. You may need to temporarily increase the dose. Monitor glucose closely.
• Type 2 diabetes on sulfonylureas (glimepiride, etc.): If you are eating very little, these can cause hypoglycemia. Your doctor may advise you to temporarily reduce or skip the dose. Do not make this decision on your own without a prior plan.
• Type 2 diabetes on metformin, DPP‑4 inhibitors, GLP‑1 agonists, or SGLT2 inhibitors: Generally continue these. However, if you have severe vomiting or diarrhoea and are at risk of dehydration, SGLT2 inhibitors should be temporarily stopped to reduce the risk of DKA and acute kidney injury. Ask your doctor about this in advance.

5. What to Eat and Drink During Illness

The goal is to stay hydrated and consume enough carbohydrates to prevent starvation ketosis while keeping blood sugar from spiking too high.

Fluids (aim for 150‑200 ml every hour):

• Water: The best choice. Sip slowly and frequently.
• Oral rehydration solution (ORS): Excellent for replacing electrolytes lost through vomiting or diarrhoea.
• Coconut water (unsweetened): Natural electrolytes.
• Clear soups and broths: Provide fluids and some salt.
• If you cannot eat solid food and your blood sugar is dropping, drink liquids containing sugar: fruit juice (diluted with water), regular soft drinks (stirred to remove fizz), or weak sweet tea.

Foods (gentle on the stomach, 15‑20 g carbs per hour if able):

• Plain curd (dahi) with a pinch of salt or sugar (depending on glucose).
• Soft khichdi (rice and dal, well‑cooked, low spice).
• Banana (small, just ripe).
• Plain toast or crackers.
• Apple sauce or stewed apple.
• Oatmeal or rice porridge (kanji).
• Boiled potato (mashed with a little salt).

Dr. Reddy advises avoiding heavy, fatty, or spicy foods during illness, as they can worsen nausea and delay stomach emptying.

6. When to Call Your Doctor or Go to the Emergency Room

Contact your doctor immediately or go to the hospital if you experience any of the following:

• Blood sugar consistently above 250 mg/dL despite taking correction insulin.
• Moderate or large ketones in the urine or blood.
• Vomiting or diarrhoea lasting more than 6 hours, especially if you cannot keep fluids down.
• Signs of dehydration: very dry mouth, sunken eyes, dark urine or very little urine, dizziness when standing.
• Difficulty breathing, fruity‑smelling breath, confusion, or extreme drowsiness — these are signs of DKA and require immediate emergency care.
• Fever above 38.5°C (101.3°F) that does not respond to paracetamol.
• Abdominal pain that is severe or persistent.
• Any change in consciousness or inability to stay awake.