DKA vs HHS
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.
Side-by-side comparison
Side-by-side2 compared
Dimension
DKA
HHS
Pathophysiology & risk
- Absolute insulin deficit then ketoacidosis
- Type 1 (or Type 2 under stress)
- Rapid onset: hours to 1–2 days
- Relative insulin deficit (blocks ketosis)
- Type 2, usually older adults
- Insidious onset: days to weeks
Signs & symptoms
- ★Kussmaul respirations (deep, rapid)
- Fruity (acetone) breath
- Abdominal pain
- Nausea/vomiting
- Alert then confused, late coma
- Profound dehydration (8–12 L deficit)
- Altered level of consciousness
- Seizures
- Coma common at presentation
- No Kussmaul or fruity breath
Diagnostics & labs
- ★Serum ketones positive
- Beta-hydroxybutyrate elevated
- Glucose > 250 (often 300–500)
- Arterial pH < 7.30 (acidosis)
- Bicarbonate < 18
- Elevated anion gap
- ★Serum osmolality > 320
- Ketones absent or trace
- Glucose > 600 (often > 1,000)
- Arterial pH > 7.30 (no acidosis)
- Bicarbonate > 18
Nursing priorities
- IV 0.9% normal saline resuscitation
- ★Insulin only after K⁺ ≥ 3.3 mEq/L
- Trend anion gap to closure
- IV 0.9% normal saline resuscitation
- ★Aggressive NS — fluids are top priority
- Monitor serum osmolality
- Monitor neurologic status
Treatment & meds
- Regular insulin IV infusion
- Add D5 when glucose ~200
- Replace potassium (K⁺)
- Replace phosphate
- Switch to subcutaneous insulin when stable
- Regular insulin IV infusion
- Replace potassium (K⁺)
- Insulin titrated more slowly
- Treat the precipitating illness
Patient teaching
- Never stop insulin
- Follow sick-day rules
- Check ketones when ill or glucose > 240
- Stay hydrated during illness
- Monitor glucose during illness
- Maintain medication adherence
- Infection is a common trigger
Red flags — escalate
- Avoid rapid glucose correction
- Hypokalemia as insulin shifts K⁺ into cells
- Hypovolemic shock from severe dehydration
- Hyperviscosity raises clot risk
Complications
- Mortality ~1–5%
- Cerebral edema (pediatric DKA)
- Mortality ~10–20% (higher)
- Venous thromboembolism (VTE)
Pathophysiology & risk
DKA
- Absolute insulin deficit then ketoacidosis
- Type 1 (or Type 2 under stress)
- Rapid onset: hours to 1–2 days
HHS
- Relative insulin deficit (blocks 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
- Alert then confused, late coma
HHS
- Profound dehydration (8–12 L deficit)
- Altered level of consciousness
- Seizures
- Coma common at presentation
- No Kussmaul or fruity breath
Diagnostics & labs
DKA
- ★Serum ketones positive
- Beta-hydroxybutyrate elevated
- Glucose > 250 (often 300–500)
- Arterial pH < 7.30 (acidosis)
- Bicarbonate < 18
- Elevated anion gap
HHS
- ★Serum osmolality > 320
- Ketones absent or trace
- Glucose > 600 (often > 1,000)
- Arterial pH > 7.30 (no acidosis)
- Bicarbonate > 18
Nursing priorities
DKA
- IV 0.9% normal saline resuscitation
- ★Insulin only after K⁺ ≥ 3.3 mEq/L
- Trend anion gap to closure
HHS
- IV 0.9% normal saline resuscitation
- ★Aggressive NS — fluids are top priority
- Monitor serum osmolality
- Monitor neurologic status
Treatment & meds
DKA
- Regular insulin IV infusion
- Add D5 when glucose ~200
- Replace potassium (K⁺)
- Replace phosphate
- Switch to subcutaneous insulin when stable
HHS
- Regular insulin IV infusion
- Replace potassium (K⁺)
- Insulin titrated more slowly
- Treat the precipitating illness
Patient teaching
DKA
- Never stop insulin
- Follow sick-day rules
- Check ketones when ill or glucose > 240
HHS
- Stay hydrated during illness
- Monitor glucose during illness
- Maintain medication adherence
- Infection is a common trigger
Red flags — escalate
DKA
- Avoid rapid glucose correction
- Hypokalemia as insulin shifts K⁺ into cells
HHS
- Hypovolemic shock from severe dehydration
- Hyperviscosity raises clot risk
Complications
DKA
- Mortality ~1–5%
- Cerebral edema (pediatric DKA)
HHS
- Mortality ~10–20% (higher)
- Venous thromboembolism (VTE)
★ marks the fact that sets a column apart.
Clinical Pearl
Ketones + Kussmaul + acidosis = DKA; extreme glucose + altered LOC + no ketones = HHS.
Play this as a game — free
Drill DKA vs HHS in Swipe Right & Speed Sort. 14-day free trial, no card required.