Diabetes Sick Day Rules: Managing Medications, Hydration, and Ketone Testing

Acute illness—such as an infection, influenza, or gastroenteritis—places stress on the body. Under physiological stress, the body releases counter-regulatory hormones (including cortisol, adrenaline, glucagon, and growth hormone). These hormones work against insulin, prompting the liver to release stored glucose and causing blood sugar levels to rise rapidly. For individuals with diabetes, this stress response increases the risk of metabolic crises: Diabetic Ketoacidosis (DKA) in type 1 diabetes, and Hyperosmolar Hyperglycemic State (HHS) in type 2 diabetes. Implementing “Sick Day Rules” is vital to managing medications, maintaining hydration, and knowing when to seek emergency care.

Essential Monitoring During Illness

When sick, the frequency of glucose testing must increase. Patients should perform Self-Monitoring of Blood Glucose every 2 to 4 hours, even during the night. If using a CGM, readings should be cross-checked with fingersticks, especially if the patient is dehydrated or taking high doses of acetaminophen, which can interfere with some CGM sensor chemistry.

Ketone testing is another essential component, particularly for individuals with type 1 diabetes or insulin-deficient type 2 diabetes. Ketones are acidic byproducts of fat metabolism that accumulate when the body lacks sufficient insulin to utilize glucose for energy. Ketones should be checked (using blood ketone meters or urine test strips) every 4 hours or whenever blood glucose exceeds 250 mg/dL (13.9 mmol/L). High levels of ketones indicate an impending risk of DKA, which requires immediate medical intervention.

💡 💡 The SADMAN Mnemonic

During acute illness, dehydrating conditions, or before major surgeries, remember the “SADMAN” medications that should be temporarily stopped: SGLT2 inhibitors, ACE inhibitors, Diuretics, Metformin, ARBs, and NSAIDs. Always resume them only when you are eating and drinking normally and are fully hydrated.

Medication Adjustments and the SADMAN Mnemonic

Managing diabetes medications during illness is complex. Patients should never stop taking their background (basal) insulin, even if they cannot eat. The liver continues to release glucose, and the body needs baseline insulin to prevent ketosis. However, short-acting or mealtime insulin may need to be adjusted or held if the patient is unable to tolerate food. For oral medications, clinicians use the “SADMAN” mnemonic to identify drugs that should be held during acute illness, particularly if there is a risk of dehydration or vomiting:

• S – SGLT2 Inhibitors: (e.g., empagliflozin, dapagliflozin) Must be held to avoid the risk of euglycemic DKA and acute kidney injury.
• A – ACE Inhibitors: (e.g., lisinopril) Held to protect kidney function during dehydration.
• D – Diuretics: (e.g., furosemide, hydrochlorothiazide) Held to prevent worsening dehydration.
• M – Metformin: Held because severe dehydration increases the risk of metformin accumulation and lactic acidosis.
• A – ARBs (Angiotensin Receptor Blockers): (e.g., losartan) Held to prevent acute kidney injury.
• N – NSAIDs (Non-steroidal Anti-inflammatory Drugs): (e.g., ibuprofen) Held due to their nephrotoxic potential during volume depletion.

Always consult your healthcare provider for specific instructions regarding medication adjustments.

Hydration and Nutritional Strategies

Dehydration is a primary driver of HHS and DKA. To prevent dehydration, patients should drink 8 ounces of sugar-free fluids (such as water, broth, or decaffeinated tea) every hour. If blood glucose is low (below 150 mg/dL) or the patient cannot tolerate solid food, they should sip carbohydrate-containing fluids (such as regular gelatin, sports drinks, or diluted juice) to provide energy and prevent starvation ketosis. The goal is to consume approximately 50 grams of carbohydrates every 3 to 4 hours, divided into small, frequent portions. If hypoglycemia occurs, treat it using the rules outlined in Recognizing and Treating Low Blood Sugar.

When to Seek Emergency Medical Attention

Sick day management at home has limits. Patients or caregivers must seek immediate emergency medical care if any of the following warning signs occur:

1. Persistent vomiting or inability to keep fluids down for more than 4 to 6 hours.
2. Blood glucose levels remaining above 250 mg/dL despite taking supplemental insulin doses.
3. Moderate or high levels of blood or urine ketones.
4. Symptoms of DKA or HHS, including deep, rapid breathing (Kussmaul breathing), fruity-smelling breath, extreme drowsiness, confusion, or severe abdominal pain.
5. Shortness of breath or difficulty breathing.

💡 Frequently Asked Questions (FAQ)

Q1: Why does illness cause my blood sugar to rise even if I cannot eat?
A1: When the body is fighting an infection or illness, it releases counter-regulatory stress hormones (such as cortisol, adrenaline, and glucagon). These hormones block the action of insulin and trigger the liver to release extra glucose into the bloodstream, leading to hyperglycemia even without oral intake.

Q2: Can I take over-the-counter cough medicines?
A2: Yes, but be cautious. Many liquid cough syrups and throat lozenges contain high amounts of sugar, which can raise blood glucose. Look for sugar-free alternatives, and consult your pharmacist for guidance.

Q3: How do I test for ketones?
A3: Ketones can be measured in urine using test strips (which turn purple in the presence of ketones) or in blood using a specialized blood ketone meter. Blood testing is preferred clinically because it measures beta-hydroxybutyrate, providing real-time data, whereas urine testing reflects ketones from several hours prior.

📚 References & Sources

1. American Diabetes Association (2024). Diabetic Ketoacidosis and Hyperosmolar Hyperglycemic State: Standards of Care. Diabetes Care, 47(Suppl. 1), S158-S178.
2. Joint British Diabetes Societies (JBDS) for Inpatient Care (2021). The Management of Diabetic Ketoacidosis in Adults.