Version 1.0 — Published April 2026
Quick Answer
Diabetic ketoacidosis (DKA) is a life-threatening complication of T1DM (and increasingly T2DM with SGLT2 inhibitors), defined by the triad of hyperglycemia (>250 mg/dL), high anion gap metabolic acidosis (pH <7.3, HCO3 <18), and ketosis. In a 22-year-old T1DM patient with 2 days of polyuria, vomiting, fruity breath and Kussmaul respirations, follow this 6-step workflow:
- Confirm DKA — capillary glucose, ABG (pH, HCO3, anion gap), serum/urine ketones, basic metabolic panel
- IV access × 2 large-bore lines and aggressive fluid resuscitation — 1-1.5 L normal saline in the first hour, then 250-500 mL/hr based on hemodynamics
- Check serum K+ BEFORE starting insulin — if K+ <3.3 mEq/L, replace K+ first; insulin can cause fatal hypokalemia
- Start IV regular insulin 0.1 U/kg/hr (no bolus needed) — target glucose fall 50-75 mg/dL/hr
- Switch fluids to D5-half NS when glucose drops to 200-250 mg/dL — continue insulin until anion gap closes
- Transition to SC insulin only after AG closure + pH >7.3 + patient eating — overlap IV and SC for 1-2 hours
The case
A 22-year-old male software student presents to the emergency department with 2 days of progressive nausea, vomiting (8-10 episodes), generalized abdominal pain, and increasing thirst. He has a 4-year history of type 1 diabetes mellitus on basal-bolus insulin (glargine 18 units at night, lispro with meals). His mother reports that he ran out of glargine 3 days ago because he was preparing for end-semester exams and "forgot to refill." For the last 24 hours, his urine output has been very high, he is too weak to walk, and his breath smells "sweet, like nail polish remover."
He denies fever, cough, dysuria, diarrhea, or chest pain. No recent travel, no alcohol, no recreational drug use. His last HbA1c (3 months ago) was 8.9 percent. No known cardiac, renal, or thyroid disease.
On arrival, vitals are: pulse 128/min regular, BP 96/58 mmHg, respiratory rate 30/min with deep sighing breaths (Kussmaul respiration), SpO2 99 percent on room air, temperature 36.8 C, capillary glucose >500 mg/dL (HI on glucometer). He is drowsy but rousable (GCS 13 — E3 V4 M6), with dry mucous membranes, sunken eyes, poor skin turgor, prolonged capillary refill 4 seconds, and a fruity acetone odor on his breath. Abdomen is mildly tender diffusely with no peritonism (DKA pseudo-peritonitis). No focal neurological deficit.
ABCD assessment and initial investigations
In suspected DKA, the priority is parallel resuscitation and diagnostic workup. The ABCD framework drives the first 30 minutes.
A — Airway: Patent. Patient protecting own airway despite drowsiness. No vomiting at this moment but place in left lateral position with suction available. NG tube if persistent vomiting and altered sensorium.
B — Breathing: Kussmaul respiration at 30/min — this is the body compensating for metabolic acidosis. Do NOT sedate or intubate prematurely; loss of compensatory hyperventilation will rapidly worsen acidosis. Pulse oximetry continuous, ABG drawn.
C — Circulation: Tachycardic, hypotensive, prolonged capillary refill — fluid-deplete (typical DKA deficit 6-9 L in adults, 100 mL/kg in children). Establish two large-bore IV lines (16-18 G), draw blood for labs, start 0.9% NaCl 1 L over the first hour.
D — Disability/Dextrose: GCS 13, capillary glucose >500 mg/dL. Check pupils, blood ketones, electrolytes. Look for precipitant (infection, MI, pancreatitis, missed insulin doses).
Initial investigations:
- ABG: pH 7.10, PaCO2 18 mmHg, PaO2 102 mmHg, HCO3 6 mEq/L, lactate 1.8 mmol/L — severe metabolic acidosis with respiratory compensation
- Anion gap: Na 134 - (Cl 96 + HCO3 6) = 32 mEq/L (markedly elevated; normal 8-12)
- Capillary blood glucose: 542 mg/dL
- Serum ketones (beta-hydroxybutyrate): 6.8 mmol/L (normal <0.6) — strongly positive
- Urine dipstick: glucose 4+, ketones 3+, no nitrites/leukocytes
- Sodium: 134 mEq/L (corrected Na = measured Na + 1.6 × [(glucose - 100)/100] = 134 + 7 = 141 mEq/L — pseudohyponatremia from osmotic shift)
- Potassium: 5.4 mEq/L (high-normal — but total body K+ is depleted by 3-5 mEq/kg)
- Chloride: 96 mEq/L
- Creatinine: 1.4 mg/dL (mildly raised, prerenal AKI from volume depletion)
- Urea/BUN: 38 mg/dL (raised)
- CBC: WBC 14,200 (DKA causes a stress leukocytosis up to 25,000 even without infection — look for left shift or fever to suggest sepsis)
- HbA1c: 11.2 percent (chronic poor control)
- Lipase, amylase: mildly raised (DKA itself raises pancreatic enzymes — does NOT diagnose pancreatitis without imaging)
- ECG: sinus tachycardia, no ischemic changes, peaked T waves consistent with hyperkalemia
- Chest X-ray: clear, no consolidation
- Urine culture, blood culture: sent (low threshold for occult infection as DKA precipitant)
Diagnosis
Severe diabetic ketoacidosis (pH 7.10, HCO3 6, AG 32, beta-hydroxybutyrate 6.8) precipitated by missed basal insulin (glargine) for 3 days in a young adult with poorly controlled T1DM (HbA1c 11.2 percent), with secondary moderate-to-severe dehydration, prerenal AKI, pseudohyponatremia, and high-normal serum potassium with predicted total body depletion.
Management — the four parallel streams
DKA management runs four streams simultaneously: fluids, insulin, electrolytes (especially K+), and treating the precipitant. The order of starting them matters — and getting K+ wrong is the most common ICU error.
Stream 1: Fluid resuscitation
Adults with DKA are typically 6-9 L fluid-deplete. Resuscitate with 0.9% normal saline, not Ringer lactate (lactate metabolism is impaired and can theoretically worsen acidosis, though balanced crystalloids are increasingly accepted in 2024 guidelines).
| Phase | Rate | Fluid |
|---|
| First hour | 1-1.5 L (15-20 mL/kg) | 0.9% NaCl |
| Hours 2-4 | 250-500 mL/hr | 0.9% NaCl if corrected Na low/normal; switch to 0.45% NaCl if corrected Na is high |
| When glucose reaches 200-250 mg/dL | 150-250 mL/hr | D5 in 0.45% NaCl (dextrose-containing fluid is critical to allow continued insulin infusion without hypoglycemia) |
Watch for: signs of fluid overload (rales, raised JVP, S3) especially in older patients or those with heart failure or renal disease. Children: limit initial bolus to 10-20 mL/kg over 1 hour to reduce cerebral edema risk.
Stream 2: Insulin therapy
Start IV regular insulin 0.1 U/kg/hr continuous infusion. ADA 2024 no longer recommends a routine 0.1 U/kg bolus — it does not improve outcomes and increases hypoglycemia/hypokalemia risk.
| Step | Action |
|---|
| 0 hr | Start regular insulin 0.1 U/kg/hr (e.g., 7 U/hr for 70 kg patient) AFTER confirming K+ above 3.3 |
| Every 1 hr | Check capillary glucose; target fall 50-75 mg/dL/hr. If glucose falls <50 mg/dL/hr in first 2 hours, double the insulin rate |
| Glucose reaches 200-250 mg/dL | Switch fluids to D5-half NS; reduce insulin to 0.05 U/kg/hr (e.g., 3-4 U/hr) |
| Anion gap closed + pH >7.3 + HCO3 >18 + patient eating | Transition to SC insulin (see Stream 4) |
Critical rule: do NOT stop insulin when glucose normalizes. DKA resolves only when the anion gap closes — glucose can normalize hours before ketones clear. Premature insulin discontinuation is the most common cause of DKA recurrence within the same admission.
Stream 3: Potassium and other electrolytes
Despite the apparently high serum K+, total body potassium is depleted by 3-5 mEq/kg. Insulin drives K+ intracellularly, and correction of acidosis does the same — within 2-4 hours of starting therapy, life-threatening hypokalemia can occur.
| Initial K+ | Action |
|---|
| <3.3 mEq/L | HOLD insulin. Replace KCl 20-40 mEq/hr until K+ >=3.3, then start insulin |
| 3.3-5.2 mEq/L | Start insulin AND add 20-30 mEq KCl per liter of IV fluid; recheck K+ every 2 hours |
| >5.2 mEq/L | Start insulin without K+ supplementation; recheck K+ every 2 hours and add KCl when K+ falls <5.2 |
For our patient (K+ 5.4): start insulin without KCl initially, plan to add 20-30 mEq/L when K+ falls below 5.2 (will happen within 1-2 hours).
Phosphate: routine replacement is NOT recommended unless severe hypophosphatemia (<1 mg/dL) with respiratory or cardiac dysfunction. Phosphate replacement can precipitate hypocalcemia.
Bicarbonate: highly controversial. ADA recommends bicarbonate ONLY if pH <6.9 (50 mmol in 200 mL water over 1 hour, with 10 mEq KCl). For pH 7.0-6.9 in this patient, use bicarbonate cautiously; for pH above 7.0, do NOT give bicarbonate — it has been associated with paradoxical CSF acidosis and worsens cerebral edema risk in children.
Magnesium: check baseline; replace if <1.5 mg/dL (low Mg perpetuates hypokalemia).
Stream 4: Transition to subcutaneous insulin
Resolution criteria (ALL must be met):
- Anion gap closed (<=12 mEq/L)
- pH >7.3
- Serum HCO3 >=18 mEq/L
- Patient alert and able to eat
- (Glucose normalization is NOT a resolution criterion)
Transition protocol:
- Give first dose of basal SC insulin (glargine 0.2-0.3 U/kg or detemir) AND short-acting prandial insulin with the next meal
- Continue IV insulin infusion for 1-2 hours after the SC dose (overlap is mandatory because SC glargine takes 1-2 hours to reach therapeutic levels)
- Stop IV insulin only after the overlap window
- Switch back to home regimen if previously well-controlled, or initiate basal-bolus regimen at total daily dose 0.4-0.6 U/kg/day (50% basal, 50% prandial split across 3 meals)
For this patient: glargine 18-22 units SC + lispro 6-8 units with each meal; education on never skipping basal insulin; refer to diabetic educator and supply 30-day insulin kit before discharge.
Stream 5: Treat the precipitant
The "5 I's" of DKA precipitants — Insulin omission, Infection, Infarction (MI/stroke), Illicit drugs/alcohol/cocaine, Iatrogenic (steroids, atypical antipsychotics, SGLT2 inhibitors causing euglycemic DKA).
For our patient, the precipitant is clearly insulin omission. No fever, no localizing signs of infection, ECG without ischemia. Cultures still sent because stress leukocytosis can mask occult infection.
Complications
1. Cerebral edema (the feared pediatric complication)
Cerebral edema occurs in 0.3-1 percent of pediatric DKA cases and carries 20-25 percent mortality. It is rare in adults. Onset typically 4-12 hours after starting therapy, although it can occur before treatment.
Risk factors:
- Age <5 years
- New-onset T1DM (first DKA presentation)
- Severe acidosis (pH <7.1) at presentation
- Low PaCO2 (deep compensation)
- High BUN (severe dehydration)
- Treatment with sodium bicarbonate
- Aggressive fluid resuscitation (>50 mL/kg in first 4 hours)
- Failure of measured Na to rise as glucose falls
Warning signs: new headache, behavioral change, decline in GCS, bradycardia with hypertension (Cushing reflex), unequal pupils, focal neurological deficit, urinary incontinence.
Treatment: elevate head of bed 30 degrees, give IV mannitol 0.5-1 g/kg over 20 minutes (or 3% hypertonic saline 5-10 mL/kg over 30 minutes), reduce IV fluid rate by 50 percent, urgent CT head to exclude alternative causes, ICU admission with neurosurgical consultation.
2. Hypokalemia
The most common iatrogenic complication. Strict 2-hourly K+ monitoring prevents it.
3. Hypoglycemia
Caused by failure to add dextrose when glucose falls to 200-250. Glucose can drop precipitously once the gap is being closed.
4. Hyperchloremic non-anion-gap metabolic acidosis
After resolution, residual acidemia from large-volume normal saline (chloride load). Self-resolves over 12-24 hours; no specific treatment.
5. Venous thromboembolism
DKA is a hypercoagulable state. Pharmacological VTE prophylaxis (LMWH) once stable.
6. Acute pancreatitis (rare)
DKA itself raises lipase/amylase up to 3× normal — do not diagnose pancreatitis on enzymes alone. Imaging (CT or USG) required if severe abdominal pain persists after metabolic correction.
How NEET PG tests DKA
NEET PG tests DKA through five recurring patterns. Knowing the pattern means you can solve the question in under 30 seconds.
Pattern 1 — The diagnostic triad question: Vignette gives glucose, pH, HCO3, ketones. Identify DKA versus HHS versus euglycemic DKA. Trap: glucose <250 with positive ketones and acidosis = euglycemic DKA (pregnancy, prolonged fasting, SGLT2 inhibitors). HHS has glucose >600, pH >7.3, HCO3 >18, minimal/absent ketones, severe hyperosmolality (>320 mOsm/kg).
Pattern 2 — The potassium question: "Initial K+ is 3.0; what next?" Answer: replace K+ first, hold insulin. Trap: answers offering "start insulin and KCl together" — wrong because insulin will worsen hypokalemia before KCl corrects it.
Pattern 3 — The fluid switch question: "Glucose has fallen to 220 mg/dL. What next?" Answer: switch fluids to D5-0.45% NaCl AND continue insulin. Trap: answers offering "stop insulin" — DKA resolves with anion gap closure, not glucose normalization.
Pattern 4 — The cerebral edema question: Pediatric DKA, headache and bradycardia 6 hours into treatment. Answer: IV mannitol 0.5-1 g/kg, slow fluids, CT head. Trap: answers offering "increase fluid resuscitation" — worsens cerebral edema.
Pattern 5 — The transition question: "When can you switch to SC insulin?" Answer: anion gap closed + pH >7.3 + patient eating + overlap IV and SC for 1-2 hours. Trap: "as soon as glucose normalizes" is wrong — premature transition causes recurrence.
High-yield one-liners:
- DKA = glucose >250 + pH <7.3 + HCO3 <18 + ketones positive
- Severity by pH: mild 7.25-7.3; moderate 7.0-7.24; severe <7.0
- Insulin 0.1 U/kg/hr; no bolus needed
- K+ <3.3 = hold insulin; K+ 3.3-5.2 = give KCl with insulin; K+ >5.2 = monitor only
- Switch to D5-half NS when glucose hits 200-250
- Resolve with anion gap closure, not glucose normalization
- Bicarbonate ONLY for pH <6.9
- Cerebral edema: age <5, new T1DM, pH <7.1; treat with mannitol or 3% saline
- Euglycemic DKA: pregnancy, SGLT2i, fasting
- HHS: glucose >600, osmolality >320, no ketones, no acidosis
Frequently Asked Questions
What are the diagnostic criteria for DKA?
ADA 2024 criteria require all three: blood glucose above 250 mg/dL (euglycemic DKA can occur with SGLT2i), arterial pH below 7.3 or venous pH below 7.25, and serum bicarbonate below 18 mEq/L, with positive serum or urine ketones (beta-hydroxybutyrate above 3 mmol/L is the most sensitive). Anion gap is elevated above 12 mEq/L. Severity is graded by pH: mild 7.25-7.3, moderate 7.0-7.24, severe below 7.0.
How do potassium shifts work in DKA management?
Despite total body potassium depletion of 3-5 mEq/kg, serum K+ is often normal or high at presentation due to insulin deficiency, acidosis, and extracellular shift. Once insulin is started and acidosis corrects, K+ moves rapidly back into cells, causing dangerous hypokalemia. Rule: if K+ is below 3.3 mEq/L, HOLD insulin and replace K+ first; if K+ is 3.3-5.2, add 20-30 mEq/L KCl to fluids; if K+ is above 5.2, monitor without supplementation but check every 2 hours.
What is the insulin protocol for DKA?
Start IV regular insulin at 0.1 U/kg/hr continuous infusion (no bolus needed in most cases per ADA 2024). Target glucose fall of 50-75 mg/dL/hr. When glucose reaches 200-250 mg/dL, switch IV fluids to D5-half normal saline and reduce insulin to 0.05 U/kg/hr. Continue insulin infusion until two criteria are met: anion gap normalizes (closure of the gap, NOT just glucose normalization) AND pH is above 7.3 with HCO3 above 18.
When and how do you transition from IV to subcutaneous insulin in DKA?
Transition only when DKA has resolved: anion gap closed, pH above 7.3, HCO3 above 18, and the patient is alert and able to eat. Give the first dose of subcutaneous long-acting insulin (glargine or detemir at 0.2-0.3 U/kg) along with short-acting prandial insulin BEFORE stopping the IV infusion. Overlap IV and SC insulin for at least 1-2 hours to prevent rebound hyperglycemia and recurrence of ketosis. Premature transition is the most common cause of DKA recurrence.
What is cerebral edema in DKA and who is at risk?
Cerebral edema is a feared complication occurring in 0.3-1% of pediatric DKA cases with 20-25% mortality. Risk factors: age below 5 years, new-onset T1DM, severe acidosis (pH below 7.1), low PaCO2 at presentation, high BUN, treatment with bicarbonate, and aggressive fluid resuscitation. Onset is typically 4-12 hours after starting therapy. Warning signs: headache, behavior change, declining GCS, bradycardia with hypertension (Cushing reflex). Treatment: IV mannitol 0.5-1 g/kg or 3% hypertonic saline, head elevation, and reduced fluid rate.
This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
Written by: NEETPGAI Editorial Team
Reviewed by: Pending SME Review
Last reviewed: April 2026
