When a person with diabetes faces a common illness like the flu or a cold, their normal glucose management routine is seriously challenged. These periods require “sick day rules” because the body’s response to infection significantly impacts blood sugar levels. Illness triggers the release of stress hormones (cortisol and adrenaline) that cause the liver to release more glucose and make cells resistant to insulin. This hormonal surge often leads to dangerously high blood glucose, increasing the risk of serious complications like Diabetic Ketoacidosis (DKA) or Hyperosmolar Hyperglycemic State (HHS). Following these guidelines is a safety measure, but they never substitute for direct medical advice from a healthcare provider.
Increased Monitoring and Ketone Testing
Illness creates an unpredictable environment for blood glucose, making increased vigilance necessary. Blood glucose levels should be checked much more frequently than usual, typically every two to four hours, even during the night, to catch rapid fluctuations. This frequent testing provides the real-time data needed to make safe adjustments to medication and fluid intake. Record the results, the time of the test, and any medication administered to share with the healthcare team.
Monitoring for ketones is mandatory, particularly for individuals with Type 1 diabetes, who are at higher risk for DKA. Ketones are acidic byproducts formed when the body breaks down fat for fuel due to a lack of accessible glucose. Testing for ketones is critical when blood glucose is elevated, generally above 250 mg/dL, though specific thresholds vary. Ketone testing uses urine strips or a blood ketone meter, with blood testing often preferred for greater accuracy and earlier detection.
The presence of moderate to large ketones signals that DKA may be developing, which is a life-threatening medical emergency. Type 2 diabetics who use insulin or take SGLT2 inhibitors should also check for ketones if glucose is high or if they experience symptoms like nausea or vomiting. Understanding ketone levels allows for timely corrective action with insulin and fluids.
Guidelines for Adjusting Medication
A fundamental rule during acute illness is that insulin therapy must be continued, regardless of appetite or vomiting. Stopping insulin, even when not eating, is dangerous because the body continues to produce glucose, and stress hormones dramatically increase insulin requirements. Individuals on insulin must often take extra doses of rapid-acting insulin to correct high blood sugar and clear ketones, guided by monitoring results.
Adjustments to oral diabetes medications are often necessary but must be made only under a doctor’s guidance. Certain medications, such as Metformin, may need to be paused if the patient is severely dehydrated or has persistent vomiting, due to the risk of lactic acidosis. SGLT2 inhibitors are often stopped temporarily during illness to prevent euglycemic DKA, where ketones are high but blood glucose is near-normal. These medications should not be restarted until the person is well and eating and drinking normally.
When using over-the-counter cold and flu remedies, check labels for hidden sugars or alcohol, which can destabilize blood sugar control. If a patient cannot eat, their mealtime insulin may be reduced, but the basal or long-acting insulin dose should generally be maintained to prevent DKA. The need for correction doses is determined by the blood glucose and ketone levels.
Managing Hydration and Nutritional Intake
Maintaining sufficient fluid intake is a paramount concern during diabetic sick days to prevent dehydration, which compounds high glucose levels and interferes with kidney function. Dehydration also makes it harder for the kidneys to flush out excess glucose and ketones. Aim to consume at least 4 to 8 ounces of fluid every hour while awake to prevent this serious complication.
The type of fluid depends on the current blood glucose level. If blood sugar is high, sugar-free, non-caffeinated drinks are preferred; however, if the patient cannot eat, they may need liquids containing carbohydrates to prevent hypoglycemia. Small, frequent sips of liquids like water, broth, or sugar-free sports drinks are easier to tolerate, especially with nausea or vomiting.
If normal meals cannot be tolerated, a target intake of approximately 50 grams of carbohydrate every three to four hours is suggested. This can be achieved through simple, easy-to-digest sources such as regular soda, fruit juice, sports drinks, gelatin, or crackers. If vomiting or diarrhea is present, contact the healthcare provider if fluids cannot be kept down for more than four hours.
Identifying Symptoms Requiring Immediate Medical Attention
The transition from managing a sick day at home to needing urgent professional care is marked by specific warning signs that indicate a worsening condition. These symptoms signal a severe dehydration risk, inability to manage blood sugar, or a medical emergency.
Immediate medical attention is required if you experience any of the following:
- Persistent vomiting or severe diarrhea, especially if unable to keep any liquids down for over four hours.
- Signs of severe dehydration, such as a dry mouth, sunken eyes, or significant weight loss during the illness.
- A sustained high fever (101°F or 38.3°C or higher) that does not respond to treatment.
- The presence of moderate to large ketones that do not decrease despite following the sick day plan.
- Blood glucose levels that remain persistently high (over 250 mg/dL) after corrective action.
- Any change in mental status, including confusion, extreme drowsiness, or difficulty breathing, which suggests DKA or HHS.