Category: Acute Internal Medicine / Emergency Endocrinology / Resuscitation
Reading Time: 8 minutes
Introduction: The High-Stakes Hyperglycemic Divide
Severe glycemic emergencies represent some of the most critical admissions arriving at the Acute Medical Unit (AMU) and Same Day Emergency Care (SDEC) unit. While Diabetic Ketoacidosis (DKA) and Hyperosmolar Hyperglycemic State (HHS) both stem from insulin deficiency and cellular metabolic stress, their pathophysiology, fluid shifts, and acute resuscitation goals differ substantially.
Mismanaging HHS by treating it like standard DKA—administering rapid IV fluid boluses and high-dose IV insulin upfront—precipitates catastrophic cerebral edema, central pontine myelinolysis, or sudden cardiovascular collapse. Conversely, delaying aggressive fluid replacement and fixed-rate insulin in DKA prolongs ketoacidosis and severe tissue hypoperfusion.
Building on our acute metabolic protocols in Hyperkalemia Emergencies in the AMU and The Acute Cardio-Renal Syndrome Matrix, navigating severe glycemic crisis requires dynamic, laboratory-guided fluid and electrolyte management.
1. Differentiating DKA vs. HHS at Front-Door Triage
While overlap occurs in up to 10% of presentations (“mixed DKA/HHS”), analyzing blood glucose, ketone levels, serum osmolality, and acid-base status provides immediate diagnostic clarity.
[Severe Hyperglycemia / Metabolic Decompensation]
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┌─────────────────────────┴─────────────────────────┐
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[Diabetic Ketoacidosis (DKA)] [Hyperosmolar Hyperglycemic State (HHS)]
• Blood Glucose > 11.0 mmol/L (or known T1DM) • Severe Hyperglycemia (≥ 30.0 mmol/L)
• Blood Ketones ≥ 3.0 mmol/L (or 2+ urine) • High Effective Osmolality (≥ 320 mOsm/kg)
• Venous pH < 7.30 or Bicarbonate < 15.0 mmol/L • Mild/Absent Ketonemia (Ketones < 1.5 mmol/L)
│ │
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【ACUTE METABOLIC KETOACIDOSIS】 【SEVERE DEHYDRATION & HYPEROSMOLALITY】
(Fixed-Rate Insulin + Rapid Fluids) (Gradual Fluid Resuscitation + Delayed Insulin)
| Diagnostic Parameter | Diabetic Ketoacidosis (DKA) | Hyperosmolar Hyperglycemic State (HHS) |
| Primary Pathophysiology | Absolute insulin deficiency $\rightarrow$ uncontrolled lipolysis | Relative insulin deficiency $\rightarrow$ extreme hyperglycemia |
| Blood Glucose | Typically $> 11.0\text{ mmol/L}$ (can be euglycemic) | Severely elevated (frequently $> 30.0–50.0\text{ mmol/L}$) |
| Blood Ketones / Acidosis | Ketones $\ge 3.0\text{ mmol/L}$; $\text{pH} < 7.30$; $\text{HCO}_3^- < 15$ | Ketones $< 1.5\text{ mmol/L}$; $\text{pH} > 7.30$; $\text{HCO}_3^- > 15$ |
| Calculated Osmolality | Variable (usually $< 320\text{ mOsm/kg}$) | Severely elevated ($\ge 320\text{ mOsm/kg}$) |
| Fluid Deficit | $100\text{ mL/kg}$ ($5–7\text{ Liters}$ average adult) | $100–220\text{ mL/kg}$ ($8–12\text{ Liters}$ average adult) |
| Mental Status | Alert to irritable (unless profound acidosis) | Lethargy, confusion, coma (proportional to osmolality) |
2. Resuscitation Protocols: DKA vs. HHS
Calculated Serum Osmolality Formula:
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| DKA RESUSCITATION MATRIX (JBDS) |
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| 1. FLUID REPLACEMENT| 0.9% Sodium Chloride: 1L in 1st hr, then 1L in 2 hrs, |
| | 1L in 4 hrs, 1L in 8 hrs. Target positive fluid balance.|
| 2. FIXED INSULIN | Continuous Fixed-Rate IV Insulin Infusion (FRIII) at |
| | 0.1 units/kg/hr. DO NOT give IV insulin bolus upfront. |
| 3. POTASSIUM RULES | Add K+ to IV fluids if K+ < 5.5 mmol/L. Keep K+ 4.0–5.0.|
| 4. GLUCOSE SWITCH | Add 10% Glucose IV when blood glucose drops < 14 mmol/L.|
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| HHS RESUSCITATION MATRIX (JBDS) |
+-------------------------------------------------------------------------------+
| 1. GRADUAL FLUIDS | 0.9% Sodium Chloride: 1L over 1st hr. Target fluid |
| | replacement over 48 hours (0.5–1.0 L/hr drop in osmol)|
| 2. DELAYED INSULIN | DO NOT start insulin at triage! Start FRIII (0.05 u/kg/hr)|
| | ONLY if glucose stops falling despite IV fluids. |
| 3. THROMBOPROPHYLAXIS| Full prophylactic low-molecular-weight heparin (LMWH) |
| | mandatory for ALL HHS admissions (extreme hyperviscosity)|
| 4. SODIUM TARGETS | Corrected Na+ should drop by < 10 mmol/L in 24 hours. |
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Why HHS Fluid Resuscitation Must Be Gradual:
In HHS, extreme extracellular hyperosmolality causes brain cells to synthesize idiogenic osmoles to prevent intracellular dehydration. Rapid drops in serum glucose or osmolality cause fluid to rush into brain cells via osmosis, precipitating fatal cerebral edema.
3. Potassium Dynamics and Metabolic Safety Checks
Potassium management is identical in both crises: insulin drives potassium into cells, causing serum levels to plummet.
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| POTASSIUM REPLACEMENT SAFETY MATRIX |
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| Serum K+ Level | Action / Infusion Supplement |
| ----------------------- | ------------------------------------------------- |
| > 5.5 mmol/L | No K+ added to current fluid bag. Re-check in 1 hr.|
| 4.0 – 5.5 mmol/L | Add 20 mmol KCl per 1000 mL 0.9% Sodium Chloride. |
| 3.5 – 4.0 mmol/L | Add 40 mmol KCl per 1000 mL 0.9% Sodium Chloride. |
| < 3.5 mmol/L | STOP insulin infusion! Push aggressive K+ replacement|
| | until K+ > 3.5 mmol/L, then restart insulin. |
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When managing severe metabolic acidosis or electrolyte shifts alongside acute kidney injury, integrate emergency protocols from Hyperkalemia Emergencies in the AMU and assess fluid responsiveness using ultrasound techniques from Point-of-Care Ultrasound (POCUS) on the Acute Take.
4. Searching for the Precipitating Trigger
Glycemic emergencies do not occur in a vacuum. Always hunt for underlying precipitating triggers using the PINCH ME and sepsis screening tools:
Occult Sepsis: Pneumonia, urosepsis, or intra-abdominal infection (see Severe Sepsis and Septic Shock in 2026: Restrictive Resuscitation).
Acute Cardiovascular Events: Silent myocardial infarction, acute PE, or stroke (see Sudden Cardiac Death in the Young: Red Flag Syncope and Massive PE vs. Cardiac Tamponade).
Frailty & Confusion: In older adults presenting with hypoactive delirium or uncharacterized functional decline, screen baseline cognition using Acute Delirium vs. Dementia on the Intake and Frailty at the Front Door: CGA and SDEC Risk Triage.
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| GLYCEMIC EMERGENCY SAFETY CHECKLIST |
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| • Hourly Capillary Blood Glucose & Ketones | Track resolution of acidosis. |
| • Repeat VBG / Electrolytes at 2, 4, 8 hrs | Monitor K+, Na+, and pH trends. |
| • Target Clearance Rates | Ketones drop ≥ 0.5 mmol/L/hr; |
| | HCO3 rise ≥ 3.0 mmol/L/hr. |
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Safety Escalation: If a patient with DKA or HHS exhibits sudden neurological decline, severe refractory hypokalemia ($\text{K}^+ < 3.0\text{ mmol/L}$), or persistent hypotension despite fluid replacement, escalate immediately to Critical Care Outreach (CCOT) under the clinical advocacy guidelines in Beyond NEWS2: Martha’s Rule, the PIER Framework, and Escalating the Deteriorating Inpatient.
Furthermore, when managing complex acute breathlessness secondary to Kussmaul breathing vs. organic airway disease, compare signs using Acute Severe Asthma vs. Acute Anaphylaxis and ADHF vs. Severe COPD Exacerbation.
