Can Nausea and Vomiting Cause Hyperglycemia?
No, nausea and vomiting do not cause hyperglycemia—rather, hyperglycemia causes nausea and vomiting, particularly when severe enough to trigger diabetic ketoacidosis (DKA), which is a life-threatening emergency requiring immediate medical intervention. 1, 2, 3
The Actual Causal Relationship
The relationship between nausea/vomiting and hyperglycemia in diabetes runs in the opposite direction from what the question suggests:
- High blood glucose levels directly cause nausea, especially when blood sugar remains elevated for extended periods 2
- Severe untreated hyperglycemia progresses to DKA, characterized by nausea, vomiting, and high ketone levels 2, 4
- Vomiting accompanied by hyperglycemia and ketosis indicates DKA, which demands urgent hospitalization with intravenous fluids and continuous insulin infusion 3, 4
When Nausea/Vomiting Can Worsen Hyperglycemia
While nausea and vomiting don't directly cause hyperglycemia, they can contribute to worsening glycemic control through several mechanisms:
- Illness-induced stress from vomiting triggers counter-regulatory hormone release (cortisol, glucagon, catecholamines), increasing insulin resistance and precipitating DKA in vulnerable patients 2
- Inability to take oral medications or food during vomiting episodes leads to missed diabetes medications and erratic insulin dosing 1
- Dehydration from vomiting causes osmotic shifts and volume depletion, exacerbating existing hyperglycemia 2, 3
Critical Immediate Actions Required
When a diabetic patient presents with nausea, vomiting, and hyperglycemia:
- Check blood or urine ketones immediately and assume DKA until proven otherwise 3, 4
- Never stop insulin during illness in type 1 diabetes, as this is the most common cause of preventable DKA 3
- Admit to ICU immediately if DKA is confirmed, with isotonic saline at 15-20 mL/kg/hour and continuous IV insulin at 0.1 units/kg/hour 3, 4
- Monitor hourly vital signs, capillary glucose, and check electrolytes every 2-4 hours 1, 3
Special Considerations
SGLT2 inhibitors significantly increase the risk of euglycemic DKA (glucose <200 mg/dL) and should be stopped immediately if DKA is suspected 2, 3. Approximately 10% of DKA cases present with normal or mildly elevated glucose if the patient is on these medications 4.
Common Pitfalls to Avoid
- Don't assume normal glucose rules out DKA in patients taking SGLT2 inhibitors 3
- Don't attribute all vomiting to gastroparesis without first excluding DKA, as vomiting with ketosis is a medical emergency 3
- Don't delay treatment waiting for ketone results if clinical suspicion for DKA is high based on symptoms 3