Diabetes NCLEX Review: Insulin, Hypoglycemia & DKA

bolt The 60-second version

check_circleHypoglycemia (glucose below 70 mg/dL): if the client can swallow, give 15 g of fast-acting carbohydrate and recheck in 15 minutes; if not, give glucagon or IV dextrose as ordered.
check_circleKnow insulin timing: rapid-acting (lispro, aspart) starts in about 15 minutes; regular in about 30 minutes; NPH peaks in about 4–12 hours; glargine has no pronounced peak.
check_circleMixing regular and NPH: draw up clear (regular) before cloudy (NPH). Never mix glargine with other insulins.
check_circleDKA priorities: IV fluids, then IV regular insulin, with close potassium monitoring; insulin drives potassium into cells.
check_circleSick-day rules: keep taking insulin (dose may need adjusting), check glucose often (about every 3–4 hours), check ketones if indicated, drink fluids, call when unable to keep fluids down.
check_circleFoot care: inspect daily, wear well-fitting shoes, never go barefoot, nail and callus care by a professional if neuropathy is present.

target What you'll be able to do · aligned to NCLEX-RN Test Plan · Physiological Integrity; Health Promotion

PHARMMatch insulin onset and peak to meals and hypoglycemia risk.
PHYS ADAPTTreat hypoglycemia with the 15-15 rule or parenteral glucose.
PHYS ADAPTPrioritize fluids, insulin, and potassium monitoring in DKA.
HEALTHTeach sick-day rules and diabetic foot care.

How diabetes is tested on the NCLEX-RN

Items span Pharmacological Therapies, Physiological Adaptation, and Health Promotion.

Low vs high. If unsure and the client is symptomatic, check glucose; if a meter is unavailable, treat as hypoglycemia, which is the faster threat.

Insulin timing and administration

Matching insulin action to meals prevents lows.

Insulin profiles as commonly taught; check the specific product labeling.

Insulin	Nursing timing point
Rapid-acting (lispro, aspart)	Give within about 15 minutes of a meal; food must be available
Regular	Give about 30 minutes before a meal; only type given IV for DKA
NPH (intermediate)	Cloudy; roll gently, do not shake; watch for lows at peak (afternoon or overnight)
Glargine (long-acting)	Once daily at the same time; do not mix

Insulin is a high-alert drug; many facilities require an independent double check.

Treating hypoglycemia

A fast, ordered response.

15-15 rule. Examples of 15 g: 4 oz (120 mL) juice or regular soda, or glucose tablets per label. Unconscious client: nothing by mouth; glucagon or IV dextrose.

DKA vs HHS

Both are emergencies with severe dehydration.

Feature	DKA	HHS
Typical client	Type 1 (can occur in type 2)	Type 2, often older adults
Glucose	≥ 200 mg/dL (2024 criteria; classically > 250) or known diabetes	Usually > 600 mg/dL
Ketones and acidosis	Present; low pH and bicarbonate	Minimal or absent
Breathing	Kussmaul respirations, fruity breath	Usually normal
Priority	IV fluids, IV insulin, potassium	Aggressive IV fluids, insulin, neuro monitoring

Potassium may look normal or high at first but falls quickly once insulin starts; protocols usually require an adequate potassium level before insulin.

Teaching and an NGN-style case

Self-management prevents emergencies.

Sick days: never skip insulin without guidance; check glucose about every 3–4 hours and ketones if advised; drink fluids; call when vomiting or unable to eat.
Rotate injection sites within the same region; inspect for lipohypertrophy.
Feet: inspect daily with a mirror, wash and dry between toes, moisturize but not between toes, wear socks and shoes.
Exercise lowers glucose; carry a fast-acting carbohydrate.
A1C reflects average glucose over about 3 months; a common target is below 7% for many adults.

functions Clinical judgment case — afternoon symptoms

A client received NPH at 0700. At 1500 they are sweaty, shaky, and confused, glucose 52 mg/dL, and can swallow. What should the nurse do?

Recognize cues: hypoglycemia symptoms at the expected NPH peak.
Analyze: the client can swallow, so oral treatment is appropriate.
Give 15 g fast-acting carbohydrate and recheck in 15 minutes.
Once stable, give a snack with protein and carbohydrate; report and review the dose.

Answer. Give 15 g of fast-acting carbohydrate (e.g., 4 oz juice) and recheck in 15 minutes.

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quiz Test yourself

Quick check — 3 questions

1. A client is unresponsive with a glucose of 38 mg/dL. The nurse anticipates:

2. When should rapid-acting insulin lispro be given?

3. Which finding is expected in DKA but not HHS?

Frequently asked questions

How is mild hypoglycemia treated?expand_more

Give 15 g of fast-acting carbohydrate, recheck glucose in 15 minutes, repeat if still below 70 mg/dL, then give a snack once stable.

Which insulin is drawn up first when mixing?expand_more

Regular (clear) is drawn up before NPH (cloudy). Glargine is never mixed.

Should a client skip insulin when sick and not eating?expand_more

No. Illness often raises glucose. The client continues insulin with guidance, checks glucose often, and calls the provider when unable to keep fluids down.

Why monitor potassium in DKA?expand_more

Insulin moves potassium into cells, so serum potassium can fall quickly and cause dysrhythmias.