Study Notes – DKA vs HHS (HHNS)

Quick Memory Trick

• DKA → D comes first → Type 1 diabetes.

• HHS → H comes later → Type 2 diabetes.

DKA (Diabetic Ketoacidosis)

• Cause: No insulin (autoimmune destruction of pancreas in Type 1).

• Pathophysiology:

  • No insulin → glucose cannot enter cells.

  • Body burns fat for fuel → ketone bodies produced.

  • Ketones = acidic → metabolic acidosis.

  • Think: like a diesel engine blowing off acidic exhaust.

• Onset: Fast (hours to days).

• Typical patient: Young, Type 1 diabetic.

• Causes (3 S’s):

  1. Sepsis (infection – #1 NCLEX cause!).

  2. Stress (surgery, illness).

  3. Skipping insulin.

• Key symptoms:

  • Ketones in urine/serum.

  • Kussmaul respirations (deep, rapid).

  • Fruity breath (acetone).

  • Abdominal pain, nausea, vomiting.

  • Dehydration, polyuria, polydipsia.

HHS / HHNS (Hyperglycemic Hyperosmolar Nonketotic Syndrome)

• Cause: Some insulin still present (Type 2).

• Pathophysiology:

  • Enough insulin to prevent fat breakdown → no ketones.

  • But not enough insulin to control glucose → extreme hyperglycemia.

  • High sugar → severe dehydration & thick blood (hyperosmolarity).

• Onset: Slow (days to weeks).

• Typical patient: Older, Type 2 diabetic.

• Causes: Illness, infection (common in elderly).

• Key symptoms:

  • Very high glucose (>600 mg/dL).

  • No ketones, no acidosis.

  • Neurological changes (confusion, seizures, coma).

  • Extreme dehydration.

Comparing DKA vs HHS

Feature	DKA (Type 1)	HHS/HHNS (Type 2)
Onset	Rapid (hours–days)	Slow (days–weeks)
Ketones	Yes – fat burn → acidosis	No – some insulin prevents ketones
Acidosis	Yes (low pH, metabolic acidosis)	No
Glucose	250–500+	> 600
Main issue	Acidosis + dehydration	Severe dehydration + hyperosmolarity
Typical patient	Young, Type 1	Older, Type 2
NCLEX favorite	Infection = #1 trigger	Infection/illness in elderly

Summary Memory Aid:

• DKA = Dieseling engine (acidic ketone exhaust, young Type 1, fast).

• HHS = High sugar, Hyperosmolar, Slowly Sick Seniors.