Case Study — Endocrine
DKA NGN Case Study
A Next Gen NCLEX-style unfolding case. Read each step, commit to your own answer — out loud or on paper — and only then reveal ours. The six steps mirror the NCSBN Clinical Judgment Measurement Model exactly as the exam tests it.
15 min activity · Endocrine
Educational use only. This case is a learning exercise with simplified values, not a treatment protocol — real DKA care follows provider orders and your facility’s DKA protocol, including its specific potassium and dextrose thresholds. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
The Scenario
2215, ED: Jordan, 19, type 1 diabetic since age 9, is brought in by roommates for a day of vomiting and “acting out of it.” They mention he’s been stressed about finals and “ran out of insulin a few days ago and was stretching what he had left.” He’s had abdominal pain since this morning.
2220 Assessment
- HR 124 · BP 98/60 · RR 30, deep and sighing · SpO₂ 99% RA · Temp 37.2°C
- Drowsy but answers questions; breath has a fruity odor
- Mucous membranes dry; skin tenting; reports intense thirst
- Diffuse abdominal tenderness, no rebound; vomited twice in triage
- Bedside glucose meter reads HIGH (above its measurable range)
Step 1 — Recognize Cues
Which findings are most relevant — and which matter most right now? List the cues you would flag before revealing.
▸Reveal answer
Most concerning cues: the deep, sighing respirations at 30 (Kussmaul breathing — the lungs blowing off acid), glucose beyond the meter’s range, tachycardia with soft BP and skin tenting (serious volume depletion), drowsiness, and fruity (acetone) breath.
The history that explains it: a type 1 diabetic rationing insulin — DKA needs only insulin absence, and stress plus missed doses is the most common student-age trigger.
The trap: anchoring on the abdominal pain and vomiting as a GI illness. DKA itself causes abdominal pain and vomiting — and a “stomach bug” story is how young DKA patients get mis-triaged.
Step 2 — Analyze Cues
Labs result: glucose 540 · pH 7.12 · HCO₃ 8 · K⁺ 5.6 · Na⁺ 131 · serum ketones large · BUN 32/Cr 1.4. What’s the full picture — and what’s deceptive about the potassium?
▸Reveal answer
DKA, confirmed: hyperglycemia + ketones + high-anion-gap metabolic acidosis (pH 7.12, HCO₃ 8). The triad is complete; HHS would show higher glucose with minimal ketones/acidosis and more profound osmolar symptoms, typically in older type 2 patients.
The potassium deception: K⁺ 5.6 looks high, but acidosis shifts potassium out of cells while urinary losses drain total-body stores — he is total-body potassium depleted despite the high serum number. The moment insulin starts, potassium rushes back into cells and the serum level can crash. This single fact drives the safety sequence of the whole treatment.
Also explained: the low-ish sodium (dilutional with hyperglycemia), the elevated BUN/Cr (prerenal from volume loss), and the drowsiness (acidosis + hyperosmolarity).
Step 3 — Prioritize Hypotheses
DKA is confirmed — so what gets fixed first, second, and third? Rank the physiologic priorities.
▸Reveal answer
1. Volume — he is liters down; isotonic fluids restore perfusion (and alone begin lowering glucose and clearing ketones). Fluids come before insulin.
2. Potassium safety — verify K⁺ and urine output before and during insulin; the falling-potassium problem is what kills DKA patients who were “responding well.”
3. Insulin to turn off ketogenesis — the drip exists to stop acid production, not just to lower glucose; it runs until the gap closes, with dextrose added as needed so it can keep running.
NGN logic: in DKA the priorities are sequenced by physiology — perfusion, then electrolyte safety, then the metabolic fix. Reversing the order is the classic exam (and real-world) error.
Step 4 — Generate Solutions
What should the first hours look like? Draft the plan you anticipate, including monitoring.
▸Reveal answer
Fluids: isotonic saline bolus then infusion per protocol — expect liters over the first hours, with reassessment of perfusion, lungs, and mental status.
Insulin: regular insulin IV infusion (commonly ~0.1 unit/kg/hr) after fluids are running and potassium is confirmed safe. No long-acting subQ chaos in the acute phase — the drip is titratable and reversible.
Potassium: add K⁺ to fluids once he’s urinating and the level drops into the protocol’s replacement range; if K⁺ were below ~3.3 at the start, insulin would be held until potassium is replaced.
Monitoring: hourly glucose; electrolytes and gap every 2–4 hours; cardiac monitor (potassium swings); strict I&O; neuro checks; and a search for a trigger (infection workup) — though insulin omission explains this one.
Step 5 — Take Action
0300, two sequencing questions: (a) glucose is now 240 mg/dL but the anion gap is still elevated and ketones persist — a colleague suggests stopping the insulin drip since “the sugar’s fixed.” (b) The repeat K⁺ is 3.2. What do you do with each?
▸Reveal answer
(a) Don’t stop the drip — add dextrose. The infusion is treating the acidosis, and ketogenesis restarts the moment insulin disappears. When glucose falls to roughly 200–250, dextrose is added to the IV fluids so the insulin can keep running until the anion gap closes. Glucose is the speedometer; the gap is the destination.
(b) K⁺ 3.2 = pause the insulin and replace potassium per protocol, then resume. This is the predicted crash: insulin drove potassium into the cells. Continuing insulin at this level invites lethal dysrhythmias — watch the monitor and recheck after replacement.
Throughout: document the trend, not just the numbers — glucose rate of fall (too-rapid drops risk cerebral edema, the feared complication especially in younger patients), mental status, and urine output.
Step 6 — Evaluate Outcomes
0900: pH 7.34 · HCO₃ 19 · gap closed · glucose 182 on insulin + D5 · K⁺ 4.1 · alert, hungry, asking for breakfast. The team plans the transition to subcutaneous insulin. What makes the transition safe — and what does discharge teaching have to address?
▸Reveal answer
Improving: gap closed, acidosis resolved, potassium stable, mentation normal — the DKA is broken.
The transition rule: give the first subcutaneous dose (including basal insulin) and overlap it with the drip for 1–2 hours before stopping the infusion — IV insulin vanishes in minutes, and a gap between drip and subQ coverage invites rebound ketosis.
The real fix is the teaching: he rationed insulin. That conversation includes never stopping insulin in illness (sick-day rules: keep taking insulin, check glucose and ketones often, hydrate, call early), affordability resources (this drives more DKA than ignorance does), stress and finals planning, and ketone strips at home. Evaluation loops to root cause — otherwise this is a readmission, not a save.
Debrief — The Pattern to Keep
- ✦Vomiting + abdominal pain + deep sighing breaths in a type 1 diabetic = DKA until proven otherwise — don't anchor on "stomach bug."
- ✦Fluids before insulin; potassium before, during, and after insulin — hold the drip if K⁺ drops below ~3.3.
- ✦A "high" admission potassium in DKA hides total-body depletion — expect the crash when insulin starts.
- ✦The insulin drip treats the acidosis: add dextrose at ~200–250 and run until the anion gap closes.
- ✦Overlap subQ (with basal) and the drip before stopping it — and treat the reason they ran out of insulin, not just the chemistry.