side by side comparison
DKA vs HHS: Two Diabetic Emergencies — Different Mechanisms, Different Presentations
Both DKA and HHS present with sky-high glucose, but picking the wrong distinguishing feature costs you the question. DKA kills with acidosis; HHS kills with dehydration and hyperosmolarity. The NCLEX expects you to match the right lab picture and clinical signs to the right emergency — fast.
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Side-by-side2 compared
Focus
Dimension
DKA
HHS
Pathophysiology & risk
- Absolute insulin deficit (ketosis)
- Type 1 (or Type 2 under stress)
- Rapid onset: hours to 1–2 days
- Relative insulin deficit (no ketosis)
- Type 2, usually older adults
- Insidious onset: days to weeks
Signs & symptoms
- ★Kussmaul respirations (deep, rapid)
- Fruity (acetone) breath
- Abdominal pain
- Nausea/vomiting
- Often alert; coma only if severe
- Profound dehydration (8–12 L deficit)
- Focal neuro deficits (mimic stroke)
- Seizures
- Coma common at presentation
- No Kussmaul or fruity breath
Diagnostics & labs
- ★Serum ketones positive
- Beta-hydroxybutyrate elevated
- Glucose > 250 (often 300–500)
- Acidosis: pH < 7.30
- Low HCO₃⁻ (< 18)
- Elevated anion gap
- ★Serum osmolality > 320
- Ketones absent or trace
- Glucose > 600 (often > 1,000)
- No acidosis: pH > 7.30
- HCO₃⁻ near normal (> 18)
Nursing priorities
- IV 0.9% normal saline resuscitation
- Insulin only after K⁺ ≥ 3.3 mEq/L
- Trend anion gap to closure
- Monitor neurologic status
- IV 0.9% normal saline resuscitation
- Insulin only after K⁺ ≥ 3.3 mEq/L
- Monitor serum osmolality
- Monitor neurologic status
Treatment & meds
- Regular insulin IV infusion
- Add D5 when glucose ~200
- Replace potassium (K⁺)
- Overlap SC insulin before stopping drip
- Regular insulin IV infusion
- Add D5 when glucose ~300
- Replace potassium (K⁺)
- Overlap SC insulin before stopping drip
Patient teaching
- Never stop insulin when ill
- Check ketones when ill or glucose > 240
- Follow sick-day rules
- Infection is a common trigger
- Stay hydrated; older adults thirst less
- Follow sick-day rules
- Infection is a common trigger
Red flags — escalate
- Anion gap not closing
- Avoid rapid glucose correction
- Hypokalemia once insulin starts
- Hypovolemic shock (severe dehydration)
- Hyperviscosity raises clot risk
- Avoid rapid glucose correction
- Hypokalemia once insulin starts
Complications
- Mortality ~1–5%
- Cerebral edema (pediatric DKA)
- Mortality ~10–20% (higher)
- Venous thromboembolism (VTE)
Pathophysiology & risk
DKA
- Absolute insulin deficit (ketosis)
- Type 1 (or Type 2 under stress)
- Rapid onset: hours to 1–2 days
HHS
- Relative insulin deficit (no ketosis)
- Type 2, usually older adults
- Insidious onset: days to weeks
Signs & symptoms
DKA
- ★Kussmaul respirations (deep, rapid)
- Fruity (acetone) breath
- Abdominal pain
- Nausea/vomiting
- Often alert; coma only if severe
HHS
- Profound dehydration (8–12 L deficit)
- Focal neuro deficits (mimic stroke)
- Seizures
- Coma common at presentation
- No Kussmaul or fruity breath
Diagnostics & labs
DKA
- ★Serum ketones positive
- Beta-hydroxybutyrate elevated
- Glucose > 250 (often 300–500)
- Acidosis: pH < 7.30
- Low HCO₃⁻ (< 18)
- Elevated anion gap
HHS
- ★Serum osmolality > 320
- Ketones absent or trace
- Glucose > 600 (often > 1,000)
- No acidosis: pH > 7.30
- HCO₃⁻ near normal (> 18)
Nursing priorities
DKA
- IV 0.9% normal saline resuscitation
- Insulin only after K⁺ ≥ 3.3 mEq/L
- Trend anion gap to closure
- Monitor neurologic status
HHS
- IV 0.9% normal saline resuscitation
- Insulin only after K⁺ ≥ 3.3 mEq/L
- Monitor serum osmolality
- Monitor neurologic status
Treatment & meds
DKA
- Regular insulin IV infusion
- Add D5 when glucose ~200
- Replace potassium (K⁺)
- Overlap SC insulin before stopping drip
HHS
- Regular insulin IV infusion
- Add D5 when glucose ~300
- Replace potassium (K⁺)
- Overlap SC insulin before stopping drip
Patient teaching
DKA
- Never stop insulin when ill
- Check ketones when ill or glucose > 240
- Follow sick-day rules
- Infection is a common trigger
HHS
- Stay hydrated; older adults thirst less
- Follow sick-day rules
- Infection is a common trigger
Red flags — escalate
DKA
- Anion gap not closing
- Avoid rapid glucose correction
- Hypokalemia once insulin starts
HHS
- Hypovolemic shock (severe dehydration)
- Hyperviscosity raises clot risk
- Avoid rapid glucose correction
- Hypokalemia once insulin starts
Complications
DKA
- Mortality ~1–5%
- Cerebral edema (pediatric DKA)
HHS
- Mortality ~10–20% (higher)
- Venous thromboembolism (VTE)
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Clinical Pearl
Ketones + Kussmaul + acidosis = DKA; extreme glucose + altered LOC + no ketones = HHS.
Component Topics
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Go further
- Commonly confusedDKA vs HHSTwo diabetic emergencies with overlapping labs but different mechanisms, ketones, and management.
- SimulatorDKA SimulatorFluids. Then potassium. Then insulin. Treat one patient in diabetic ketoacidosis, one decision at a time. Every wrong move runs before you rewind it.
- TopicDiabetic Ketoacidosis — DKAA blood glucose of 350 mg/dL with a pH of 7.2 and fruity breath tells you the body is burning fat for fuel — and the acid it produces can kill before the sugar does.
- TopicHyperglycemic Hyperosmolar State — HHSBlood glucose hits 1,200 mg/dL but there are no ketones and no Kussmaul respirations — the patient is obtunded and profoundly dehydrated. Missing HHS kills faster than DKA.