遷延する意識障害の原因が低リン血症と考えられた糖尿病性ケトアシドーシスの1症例

A Case of Diabetic Ketoacidosis with Hypophosphatemia as the Cause of Persistent Impaired Consciousness

要旨

　70歳代，女性，糖尿病性ケトアシドーシス（diabetic ketoacidosis：DKA）の治療により検査値は改善したが意識障害が遷延した。血清リンが0.2mmol・l^－1と低下しており，重度の低リン血症が原因と考えられた。DKAは重度の低リン血症を合併することがあり，早期から血清リン測定を考慮すべきである。

　We describe the case of a patient with diabetic ketoacidosis（DKA）in which hypophosphatemia was the cause of prolonged impaired consciousness. The patient was a woman in her 70s for whom treatment for DKA was initiated. Although her laboratory findings improved with this treatment, her impaired consciousness persisted. On the day 2 of treatment for DKA, laboratory testing revealed that the patient’s serum phosphate level had decreased to 0.2 mmol・dL^－1, which was the cause of the prolonged impaired consciousness. The patient’s consciousness was restored by day 3. This case demonstrates that（ⅰ）DKA can be complicated by severe hypophosphatemia, and（ⅱ）the serum phosphate level of patients with DKA should be assessed early in the clinical course.