Diabetic Ketoacidosis Advanced Nursing Guide

DKA Pathophysiology

DKA results from absolute or relative insulin deficiency combined with excess counter-regulatory hormones (glucagon, cortisol, catecholamines). This causes: hyperglycaemia → osmotic diuresis → dehydration + electrolyte loss; and unregulated lipolysis → free fatty acids → ketogenesis → metabolic acidosis.

DKA Diagnostic Criteria (ADA/JBDS)

Parameter	Threshold
Blood glucose	>11 mmol/L (200 mg/dL) OR known diabetes
Blood/urine ketones	Blood ketones ≥3.0 mmol/L OR urine ketones ≥2+ on dipstick
Venous bicarbonate	<15 mmol/L
pH	Venous <7.3

All three criteria must be met for formal DKA diagnosis.

DKA Severity Classification

Severity	pH	Bicarbonate	Blood Ketones	Consciousness
Mild	7.25–7.30	15–18	3–6 mmol/L	Alert
Moderate	7.00–7.24	10–15	3–6 mmol/L	Alert/Drowsy
Severe	<7.00	<10	>6 mmol/L	Stupor/Coma

Common Precipitants (Sick Day Rules)

Infection: Most common precipitant — especially UTI, pneumonia, skin/soft tissue infection
New-onset T1DM: 20–30% present with DKA at diagnosis
Insulin omission: Patient stopped insulin (cost, illness, error); pump failure
Acute illness: MI, pancreatitis, stroke — counter-regulatory hormone surge
Drugs: Corticosteroids, SGLT2 inhibitors (euglycaemic DKA — glucose may be normal/mildly elevated)
Pregnancy: Increased insulin requirements; higher DKA risk even at lower glucose levels

Investigations

Bedside / Point-of-Care

Blood glucose: Glucometer (confirm with lab)
Blood ketones: Beta-hydroxybutyrate meter (Abbott Optium or similar) — most important monitoring parameter during treatment
Capillary/venous blood gas: pH, bicarbonate, pCO₂, potassium (VBG acceptable; arterial only if respiratory concern)
ECG: Hypokalaemia (flat T waves, U waves) or hyperkalaemia (peaked T waves) on presentation

Laboratory Investigations

Test	Expected Finding	Purpose
Serum glucose	Usually 14–40 mmol/L	Confirm; guide dextrose addition
Serum potassium	May be high, normal or low initially — total body K⁺ always DEPLETED	Critical — guide replacement
Sodium	Often low (pseudohyponatraemia) or high; correct for glucose	Hydration monitoring
Urea/creatinine	Elevated — pre-renal AKI from dehydration	Renal function baseline
FBC	Leucocytosis (DKA itself; not always infection)	Infection screen
Urinalysis	Glycosuria, ketonuria	Infection screen — MSU for culture
Blood cultures	Positive if bacteraemia/sepsis precipitant	If febrile or suspected infection
HbA1c	Elevated (chronic poor control)	Chronic glycaemic assessment
Lipase/amylase	May be elevated (acute pancreatitis precipitant)	If abdominal pain prominent

Potassium paradox: Serum K⁺ may be HIGH at presentation (acidosis shifts K⁺ extracellular) but total body K⁺ is severely depleted. As insulin is given and acidosis corrects, K⁺ shifts intracellular → rapid hypokalaemia. Monitor 1–2 hourly and replace aggressively.

DKA Treatment Protocol (JBDS/NICE-Based)

Step 1 — IV Fluid Resuscitation

0.9% NaCl (normal saline) is the standard first-line fluid. Avoid Hartmann's (lactate may worsen acidosis in theory — though recent trials show equivalence). Use 0.45% NaCl only in hyperosmolar/hypernatraemic DKA.

Time	Volume	Rate
0–30 min (initial resuscitation)	500 mL–1000 mL 0.9% NaCl	Over 15–30 min (shock bolus if haemodynamically compromised)
0–1 hr	1000 mL 0.9% NaCl	1 L/hr
1–3 hrs	2000 mL 0.9% NaCl	1 L over 2 hrs
3–6 hrs	2000 mL 0.9% NaCl	1 L over 2 hrs
6–12 hrs	2000 mL 0.9% NaCl	1 L over 4 hrs

When blood glucose falls to <14 mmol/L → ADD 10% dextrose at 125 mL/hr alongside 0.9% NaCl to prevent hypoglycaemia whilst continuing insulin to clear ketones.

Step 2 — Fixed-Rate IV Insulin Infusion (FRIII)

Rate: 0.1 units/kg/hr of Actrapid (soluble insulin) in 0.9% NaCl (50 units in 50 mL = 1 unit/mL)
DO NOT give IV bolus of insulin — increases risk of hypokalaemia and cerebral oedema
Withhold long-acting insulin? NO — continue background (basal) insulin at usual dose; this prevents rebound ketosis
Do NOT reduce insulin rate if blood glucose falls — instead add 10% dextrose to maintain glucose 10–14 mmol/L while keeping insulin running
Insulin target: Ketones fall at ≥0.5 mmol/L/hr; bicarbonate rise ≥3 mmol/L/hr

If ketones not falling at expected rate after 1 hour: check infusion pump, line, and consider increasing insulin rate to 0.15 or 0.2 units/kg/hr — escalate to senior.

Step 3 — Resolution Criteria (JBDS)

Parameter	Target
Blood ketones	<0.6 mmol/L
Venous pH	>7.3
Bicarbonate	>18 mmol/L
Blood glucose	<14 mmol/L (not needed if other criteria met)

When resolution criteria met AND patient eating + drinking → switch to subcutaneous insulin. Continue IV insulin for 30–60 min after first SC dose to prevent rebound ketosis.

Potassium Replacement — Critical Protocol

NEVER start insulin if serum K⁺ <3.5 mmol/L. Insulin drives K⁺ into cells — hypokalaemia before insulin risks fatal cardiac arrhythmia. Correct K⁺ first.

Potassium Replacement Protocol

Serum K⁺	Action
<3.5 mmol/L	HOLD insulin. Replace K⁺ (40 mmol/hr via central line) until K⁺ ≥3.5, then start insulin
3.5–5.5 mmol/L	Add 40 mmol KCl to each litre of IV fluid (0.9% NaCl bag); start insulin
>5.5 mmol/L	No K⁺ in IV fluid initially; recheck in 1 hour; monitor ECG

Monitoring Frequency

Parameter	Frequency
Blood glucose (BGL)	Hourly
Blood ketones	Hourly (or 2-hourly if ketones <3)
Venous blood gas (pH, HCO₃, K⁺)	Every 2 hours
Electrolytes (U&E)	Every 2–4 hours
Fluid balance	Hourly urine output; IDC in severe DKA or unconscious patient
Neurological observations	Every 1–2 hours — cerebral oedema watch

Cerebral Oedema — Most Feared Complication

Predominantly in children and young adults. Warning signs: sudden headache, confusion, change in behaviour, bradycardia, pupillary changes, deteriorating GCS during treatment.

Prevention: Avoid rapid fluid replacement; replace deficit over 24–48 hours in children; do not let glucose fall too quickly
Treatment: Mannitol 0.5–1 g/kg IV over 20 min (or hypertonic saline if no mannitol); restrict IV fluids; neurosurgery consult; consider intubation
Risk factors: Very young, new-onset DM, severe acidosis, very high BUN, bicarbonate administration (avoid routine NaHCO₃)

GCC-Specific Context

DKA in the GCC

Highest rates globally: GCC has among the world's highest rates of DKA admission — driven by high T1DM/T2DM prevalence, poor glycaemic control and late presentations
Presentation at DM diagnosis: 40–50% of new T1DM in GCC children present in DKA — reflects delayed recognition of early symptoms in primary care
Ramadan fasting: DKA risk increases during Ramadan in T1DM patients who attempt fasting — insulin omission, dehydration, altered eating schedules. Saudi ADA guidelines provide specific Ramadan DKA management protocols
SGLT2 inhibitors (gliflozins): Increasingly used in GCC for T2DM — cause euglycaemic DKA where blood glucose may only be 11–14 mmol/L. High index of suspicion required; check ketones in any unwell diabetic on gliflozins
Heat and dehydration: Summer heat exacerbates fluid losses; DKA presentations increase in summer months across the GCC

Exam Tips — DHA/SCFHS/QCHP

DKA diagnostic triad: glucose >11 + ketones ≥3 + pH <7.3 or HCO₃<15
Never bolus IV insulin in DKA — cerebral oedema risk
Potassium rule: NEVER start insulin if K⁺ <3.5
Total body K⁺ is always depleted in DKA even if serum level high
When glucose <14 mmol/L → add 10% dextrose, continue insulin
Resolution = ketones <0.6 mmol/L + pH >7.3 + HCO₃ >18
Continue basal insulin during DKA treatment
SGLT2 inhibitors → euglycaemic DKA — important GCC exam topic

Exam MCQs — DHA / SCFHS / QCHP

Q1. A patient with DKA has serum potassium of 3.1 mmol/L. The fixed-rate insulin infusion is about to be started. What is the CORRECT action?

A) Start insulin immediately — hypokalaemia can be corrected after insulin begins B) Hold insulin; replace potassium until K⁺ ≥3.5 mmol/L, then start insulin C) Start insulin and add 20 mmol KCl to the next litre of saline D) Administer oral potassium supplementation and start insulin simultaneously

✅ B — Never start insulin when K⁺ <3.5 mmol/L. Insulin drives potassium intracellularly. Starting insulin with an already low K⁺ risks life-threatening hypokalaemia and cardiac arrhythmia. Correct K⁺ first (IV replacement via central or large peripheral line), then start insulin when K⁺ ≥3.5.

Q2. After 4 hours of DKA treatment with fixed-rate insulin, a patient's blood glucose has fallen from 28 mmol/L to 11 mmol/L. Ketones are still 3.8 mmol/L and pH is 7.18. What is the APPROPRIATE action?

A) Stop insulin infusion — glucose has reached safe level B) Reduce insulin rate to 0.05 units/kg/hr to prevent hypoglycaemia C) Continue insulin at same rate; add 10% dextrose infusion to prevent hypoglycaemia while insulin clears ketones D) Switch to subcutaneous insulin — DKA is resolving

✅ C — DKA resolution requires ketone clearance (target <0.6 mmol/L) AND pH >7.3. Ketones are still high. Do NOT stop or reduce insulin. Add 10% dextrose infusion to maintain glucose 10–14 mmol/L whilst continuing insulin to clear ketones. Stopping insulin prematurely leads to rebound ketosis.

Q3. A child with DKA develops sudden headache, confusion and bradycardia after 6 hours of treatment. What complication should be suspected and what is the IMMEDIATE treatment?

A) Hypoglycaemia — administer 50% dextrose IV bolus B) Cerebral oedema — administer mannitol 0.5–1 g/kg IV and restrict fluids C) Hypokalaemia — administer 40 mmol KCl IV over 30 minutes D) Expected sign of DKA resolution — continue monitoring

✅ B — Cerebral oedema is the most feared complication of DKA in children and young adults. Warning signs: headache, confusion, behaviour change, bradycardia, pupillary changes. Immediate treatment: mannitol 0.5–1 g/kg IV over 20 minutes OR hypertonic saline. Restrict IV fluids. Urgent CT head and critical care team.

Q4. Which finding CONFIRMS DKA resolution and allows transition to subcutaneous insulin?

A) Blood glucose <6 mmol/L for 2 consecutive readings B) Urine ketones negative on dipstick C) Blood ketones <0.6 mmol/L, venous pH >7.3, bicarbonate >18 mmol/L, patient eating and drinking D) Blood glucose <14 mmol/L and patient alert

✅ C — The JBDS criteria for DKA resolution: blood ketones <0.6 mmol/L AND venous pH >7.3 AND bicarbonate >18 mmol/L, plus patient clinically stable and eating/drinking. Urine ketones lag behind blood ketones and should not be used as the primary resolution marker.

🩸 Diabetic Ketoacidosis (DKA) — Advanced