Diabetic ketoacidosis (DKA) affects 1-3 percent of pregnancies complicated by diabetes but can result in significant morbidity and mortality for mother and foetus. Euglycaemia in DKA is a recognised but infrequent presentation. It was originally defined as initial blood glucose less than 16.7 millimol per litre and bicarbonate less than 10 millimol per litre.
A 29-year old female with type 1 diabetes for 10 years presented at 25 weeks gestation with a 2 day history of vomiting and abdominal pain. General and systemic examination was unremarkable apart from mild epigastric tenderness. Blood glucose was 14.1 millimol per litre. Urinalysis showed +++ ketones but was negative for glucose. She was admitted for observation and obstetric review. Twelve hours later she was seen with a respiratory rate of 40 and heart rate 120. Blood glucose was 13.4 and arterial blood gas showed pH 7.095, pCO2 0.86kPa, pO2 17.1kPa, bicarbonate 5.9 millimol per litre, lactate 1.4 millimol per litre and base excess minus 28.1. She was admitted to ITU and treated with intravenous fluids and insulin sliding scale. The acidosis improved and she was discharged from ITU 3 days later but was closely monitored on the maternity unit for the remainder of her pregnancy. She delivered a healthy baby at 37 weeks and both were well at last postnatal follow up.
DKA can and does occur without abnormally high glucose levels.
Predisposing factors for this in pregnancy include reduced carbohydrate intake secondary to vomiting, starvation-induced ketone production, continuous uptake of glucose by the foetus and the presence of sufficient exogenous insulin to prevent hepatic glycogenolysis.
Type 1 diabetic patients presenting unwell should have urine or blood tested for ketones and arterial blood gas analysis to exclude DKA, whatever their blood glucose level.