Diabetic ketoacidosis

WARNING

Note that mixed picture DKA and HHS can and do occur

Assessment

History

• Presentation: Dry, abdominal pain, polyuria, weight loss, coma
• Risk factors: non-compliance, illness, newly diagnosed
• Review of symptoms to rule find out possible precipitant (infection, MI, pneumonia, GI illness)
• Normal insulin regime
• Diabetic control
• Previous DKA / admissions
• Previous ICU admissions

Examination

• Assess volume status
• Assess for signs of a cause (e.g. infection)
• GCS
• Work of breathing

Investigations

• ABG
• Electrolytes
• Osmolality
• Urinalysis: ketones
• Pregnancy test
• Standard investigations to rule out cause: FBC, ECG, CXR

Severity Assessment

• The focus of DKA management is glucose management while the focus of HHS management is fluid replacement

Parameter	DKA – Mild	DKA – Moderate	DKA – Severe	HHS
pH	7.25–7.30	7.00–7.24	<7.00	>7.30
Ketones (mmol/L)	1.5–3	>3	>3	<3
HCO₃⁻ (mmol/L)	15–18	10–14	<10	>18
Osmolality (mmol/L) (calculated)	Variable	Variable	Variable	>320
Blood glucose level (BGL) (mmol/L)†	>11	>11	>11	>33

• †: Euglycaemic DKA can occur in pregnancy, in known T1DM, and in patients on SGLT2 inhibitors
• Calculation of osmolality can be performed using the following formula:

$$\text{Calculated Osmolality}=2\times [\mathrm{Na}{}^{+}]+[\mathrm{Glucose}]+[\mathrm{Urea}]$$

Management

WARNING

Intravenous insulin infusions are resource intensive and are potentially dangerous because of the rapid drop in potassium and/or glucose which can occur. If insulin infusions are commenced in the emergency department, use half dose insulin infusion rates (see flowchart) until the patient can be moved to the ICU or similar specialist area

• Goals of management:
  • Establish precipitant and treat
  • Assess severity of metabolic derrangement
  • Cautions fluid resuscitation
  • Insulin
  • Replacement of electrolytes
• Monitor patients with:
  • Hourly vital signs including a GCS
  • Telemetry if replacing potassium quickly

Insulin Therapy

• Aim to lower BGL by 1-2 mmol/L/hr
• Correct osmolality by 3 mosmol/kg/hr

IV Fluid Replacement

Correct Sodium for Hyperglycaemia

Ensure correction of sodium for hyperglycaemia. Seek advice regarding fluid replacement if calculated sodium >145 mmol/L.

$$\text{Sodium (corrected)}=\text{Sodium (measured)}+\frac{\text{Blood glucose}}{4}$$

Potassium Replacement

• Check potassium levels 1-2 hourly; cardiac monitoring is often required
• If potassium level is:

  • 5.5 mmol/L

    • Do not give potassium
  • 4.5-5.5 mmol/L
    • Give 20 mmol $\mathrm{KCL}$ in 1L 0.9% sodium chloride over 2 hours
  • 3.5-4.5 mmol/L
    • Peripheral access ⇒ 20 mmol $\mathrm{KCl}$ in 1L 0.9% sodium chloride over 2 hours
    • Central access ⇒ 20 mmol $\mathrm{KCl}$ in 0.9% sodium chloride over 1 hour
  • <3.5 mmol/L
    • Do not start insulin until $\mathrm{K}{}^{+}$ corrected
    • Peripheral access ⇒ 20 mmol $\mathrm{KCl}$ in 1L 0.9% sodium chloride over 2 hours
    • Central access ⇒ 20-40 mmol $\mathrm{KCl}$ in 0.9% sodium chloride over 1 hour

Supportive Management

• Magnesium <0.8 mmol/L ⇒ Replace with $\mathrm{MgSO}{}_4$ 10mmol over 4 hours IV
• Phosphate <0.32 mmol/L ⇒ Replace with $\mathrm{KH}{}_2\mathrm{PO}{}_4$ 20mmol over 4 hours IV
• IV anti-emetic
• Assess and appropriately manage precipitating factors (e.g. MI, infection, overdose and non-adherence to insulin)

Sources

• ACI website:
  • Management of diabetic ketoacidosis and hyperosmolar hyperglycaemic state clinical tool | Emergency Care Institute
  • aci.health.nsw.gov.au/__data/assets/pdf_file/0004/699097/ACI-Management-diabetic-ketoacidosis-hyperosmolar-hyperglycaemic-state-adults-ED-flow-chart.pdf
• LITFL:
  • Diabetic Ketoacidosis • LITFL • CCC Endocrine
• IBCC:
  • Diabetic Ketoacidosis (DKA) - EMCrit Project