A 20 year old male is brought to ED by his friends with generalised malaise and weakness for last 3 days . He is confused and looks unwell.
HR 120, BP 100 systolic, afebrile, RR 28, sats 95 RA, GCS 14 confused. His VBG result is as followed.
| PH 7.08 ( 7.35 – 7.45) lactate 2.5 ( 0.2 – 1.8) | |
| PCO2 21 ( 35 – 45) Hb 168 | |
| HCO3 16 ( 22 – 28) | |
| BSL 50 ( 3.6 – 7.7 ) | |
| Na 153 (135 – 145) | |
| K 2.2 ( 3.5 – 5.5) | |
| CL 117 ( 95 – 110) |
Answer 1. High anion gap metabolic acidosis: 153 – ( 117 + 16 ) = 20.
Compensation: Expected CO2 = 1.5 X HCO3 + 8 = 32 , means fully compensated.
Delta Gap = Change in AG / Change in HCO3 = 8/8 = 1 means HAGMA.
Answer 2 : Diabetic ketoacidosis.
Answer 3: Hypernatremia ( severe )
Corrected Na in setting of high BSL Glu-10/3 + Na = 166. High Na in setting of DKA is rare. ( Explanation below)
Hypokalemia: Acidosis is usually associated with hyperkalemia because of H+ and K + exchange. ( explanation below)
Explanation: DKA with hypernatremia is not very common. Usually low Na is seen because of increased pulling of water into ECF secondary to high BSLs. .But this patient has lost excess of body water for Na resulting in hypernatremia. Corrected Na needs to be calculated in the presence of high BSL.
For every 1 point drop in PH K+ should go up by 0.5 mmol in acidosis, but in this patient K is already significantly low , meaning judicious K replacement is required. As acidosis is corrected K will start falling and will need ongoing replacement.
Management in this patient involves: 1. Fluid bolus with Nacl 0.9 % initially 1 L over an hour because patient needs volume to overcome extremely high osmolality. Following that Ongoing fluid should be 0.45 Nacl titrated accordingly with aim to decrease NA not more than 12 mmol over 24 hours.
2: K replacement first before starting insulin infusion , Mg replacement.
3. Disposition should be HDU/ ICU with close GCS monitoring.