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Commonly confused in nursing

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.

Which One Is It?

1 / 3 · score 0

The finding: Kussmaul respirations (deep, rapid)

Side-by-side comparison

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)

★ 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. Free to start, no card required.

Read the full DKA vs HHS learning module

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