---

Neonatal Hyperglycemia

Definition

• Serum glucose >125 mg/dL (>6.9 mmol/L) in term infants
• Serum glucose >150 mg/dL (>8.3 mmol/L) in preterm infants

• The Harriet Lane Handbook (23rd ed.), p. 648

---

Pathophysiology

1. Defective proinsulin processing - immature pancreatic beta cells cannot efficiently convert proinsulin to active insulin
2. Relative insulin resistance - peripheral tissues (particularly muscle) respond poorly to insulin, partly due to elevated counter-regulatory hormones
3. Impaired first-phase insulin secretion - glucose-stimulated insulin release is blunted in very preterm infants
4. Elevated stress hormones - cortisol, glucagon, and catecholamines drive gluconeogenesis and glycogenolysis, overwhelming the system

---

Causes / Etiology

Iatrogenic (Most Common)

• Excessively rapid IV dextrose infusion, especially in VLBW infants (<1.5 kg) in the first few days of life
• Total parenteral nutrition (TPN) with high glucose load

Physiological Stress

• Sepsis (especially fungal sepsis - poses particular risk)
• Hypoxia / respiratory distress syndrome (RDS)
• Surgery or surgical stress
• Intraventricular hemorrhage (IVH)

Prematurity-Related

• Preterm infants (<28-32 weeks) have the highest risk due to immature insulin secretion and peripheral resistance

Medications

• Corticosteroids (dexamethasone, hydrocortisone)
• Theophylline / caffeine
• Lipid infusions
• Vasopressors (dopamine, epinephrine)
• Diuretics

Rare / Genetic Causes

• Transient neonatal diabetes mellitus (TNDM) - rare, self-limited; usually occurs in small-for-gestational-age (SGA) infants; commonly due to abnormalities at chromosome 6q24 or KCNJ11/ABCC8 mutations
• Permanent neonatal diabetes mellitus (PNDM) - persists beyond 6 months
• Congenital hyperinsulinism paradox states

---

Risk Factors

---

Clinical Features

• Dehydration and weight loss (osmotic diuresis with glucosuria)
• Polyuria / glucosuria
• Temperature instability
• Feeding difficulties
• In severe/untreated cases: intracranial hemorrhage (due to hyperosmolality)
• Signs of the underlying condition (sepsis, respiratory distress, etc.)

Note: Neonates are typically asymptomatic from hyperglycemia itself at lower levels; hyperglycemia is often detected incidentally on glucose monitoring.

---

Complications

• Intracranial hemorrhage - hyperosmolality from high serum glucose increases IVH risk, especially in preterm infants
• Intraventricular hemorrhage - worsened by osmotic stress
• Increased mortality and morbidity in VLBW and ELBW infants (though causality vs. severity of illness remains debated)
• Retinopathy of prematurity - hyperglycemia is an independent risk factor
• Neurodevelopmental impairment
• Osmotic damage at the cellular level

---

Diagnosis

1. Bedside glucose (glucometer) - for screening/monitoring; note: bedside strips can underestimate true serum glucose
2. Confirmatory serum/plasma glucose - always confirm with laboratory measurement before initiating insulin
3. Urinalysis - check for glucosuria (indicates >180 mg/dL renal threshold exceeded)
4. Electrolytes - hyponatremia (dilutional), hyperosmolality
5. Serum osmolality - calculate or measure
6. CBC with differential - rule out sepsis
7. Blood/urine/CSF cultures - if sepsis suspected
8. C-peptide and insulin levels - if TNDM/PNDM suspected (persistent or severe hyperglycemia)
9. Genetic testing - if neonatal diabetes mellitus suspected (6q24, KCNJ11, ABCC8)

---

Management

Step 1: Address Underlying Cause

• Treat sepsis with antibiotics/antifungals
• Reduce physiological stress
• Discontinue or reduce offending medications (steroids, vasopressors if feasible)

Step 2: Reduce Glucose Infusion Rate (GIR)

GIR = [IV rate (mL/kg/day) × dextrose concentration (%)]/144

• Reduce GIR by 1-2 mg/kg/min every 2 hours
• Target GIR of 4-7 mg/kg/min (minimum needed for brain metabolism and to prevent catabolism)
• Do not reduce below 4 mg/kg/min, as this may compromise nutrition and cause hypoglycemia
• Monitor glucose every 2 hours during GIR adjustments
• Also monitor for glucosuria

Step 3: Insulin Therapy (for Persistent Hyperglycemia)

• Use continuous IV insulin infusion (not bolus)
• Start at 0.01-0.05 units/kg/hour (some protocols start at 0.01 units/kg/hour)
• Titrate up to 0.1 units/kg/hour based on glucose response
• Mix in 10% dextrose; adjust independently from the maintenance IV
• Consider a separate insulin syringe running alongside maintenance to allow independent titration

Caution: Insulin responses in neonates are unpredictable. Monitor serum glucose every 30-60 minutes when starting insulin. Risk of hypoglycemia and hypokalemia is significant.

• MSD Manual (Merck Manual Professional)
• StatPearls - Neonatal Hyperglycemia (NCBI, 2024-2025)

---

Summary Table (Harriet Lane, p. 648)

---

Special Entity: Transient Neonatal Diabetes Mellitus (TNDM)

• Rare; incidence ~1 in 400,000 live births
• Typically presents in first 6 weeks of life in SGA infants
• Causes: abnormal imprinting at chromosome 6q24 (most common), or mutations in KCNJ11 or ABCC8 (potassium channel subunits controlling insulin secretion)
• Resolves spontaneously, usually by 12-18 months, but ~50% relapse with type 2 diabetes in adolescence/adulthood
• Management: insulin infusion acutely; sulfonylureas for KCNJ11/ABCC8 mutations

---

Key Points

• Hyperglycemia in neonates is most commonly iatrogenic (excess IV dextrose) or due to physiological stress (sepsis, hypoxia)
• The cornerstone of management is reducing GIR and treating the underlying cause
• Insulin is reserved for persistent hyperglycemia; use with extreme caution due to risk of hypoglycemia
• VLBW and ELBW infants are at highest risk
• Always confirm bedside glucose with a laboratory serum value before initiating insulin

---

Acute Correction of Potassium Disorders in Neonates

Normal Potassium Range in Neonates

Always confirm with a non-hemolyzed venous or arterial specimen. Capillary samples are often spuriously elevated due to hemolysis.

• Harriet Lane Handbook (23rd ed.), p. 648 - Electrolyte Requirements Table
• NHSGGC Neonatal Hyperkalaemia Guideline

---

PART 1: NEONATAL HYPERKALEMIA

Definition

• Serum K+ >6.5 mmol/L (in a non-hemolyzed sample) - most neonatal guidelines
• Some NICU protocols use >6.0 mmol/L as threshold requiring monitoring
• >7.0 mmol/L = severe; high risk of fatal arrhythmia

Types

• Occurs in extremely preterm infants (<28 weeks) and ELBW (<1000g) without renal impairment
• Serum K+ typically peaks at 24-48 hours of life
• Mechanism: shift of K+ from intracellular to extracellular compartment due to immature Na+/K+-ATPase pump activity, cell catabolism, and deficient aldosterone response

Causes

ECG Changes (Progressive with Rising K+)

1. Peaked/tall T waves (early, K+ >6.5)
2. Prolonged PR interval
3. Widened QRS
4. Sine wave pattern
5. Ventricular fibrillation / asystole (terminal)

---

Acute Management of Neonatal Hyperkalemia

Step 0: IMMEDIATE Actions (ALL cases)

• STOP all potassium administration immediately - IV fluids, TPN, feeds
• Replace TPN with 0.18% NaCl + 10% dextrose or plain 10% dextrose at maintenance
• Review all medications - stop potassium-sparing drugs (spironolactone, indomethacin) and nephrotoxic drugs
• Obtain 12-lead ECG stat
• Confirm K+ with venous/arterial blood gas

---

Tiered Management by Severity

Tier 1: K+ 6.0-7.0 mmol/L, NO ECG changes

• Remove all exogenous K+ sources
• Rehydrate if volume-depleted
• Repeat ECG and serum K+ in 2-4 hours
• Consider furosemide (see below) if renal function adequate

Tier 2: K+ 6.0-7.0 mmol/L WITH ECG changes, OR K+ >7.0 mmol/L

---

Drug Treatments - Detailed Doses

1. Calcium Gluconate 10% - Cardiac Stabilization (FIRST-LINE, acts within minutes)

• Purpose: Stabilizes myocardial membrane; does NOT lower serum K+
• Dose: 100 mg/kg IV (= 1 mL/kg of 10% calcium gluconate) over 10-30 minutes via central or peripheral line
• Onset: Within 1-3 minutes
• Duration: 30-60 minutes only - must be followed by K+-lowering agents
• Monitoring: ECG continuously; check serum calcium
• Repeat if ECG abnormalities persist

Avoid in hypercalcemia. Causes tissue necrosis if extravasation occurs.

---

2. Insulin + Dextrose - Shifts K+ into Cells (acts within 15-30 min)

• Purpose: Insulin drives K+ intracellularly via Na+/K+-ATPase stimulation
• Protocol:
  • Bolus: Regular insulin 0.05 units/kg IV + D10W 2 mL/kg simultaneously
  • Infusion: Insulin 0.05-0.1 units/kg/hour + D10W at maintenance rate
• Onset: Within 15 minutes
• Monitoring: Blood glucose every 15-30 minutes for at least 6 hours - high risk of hypoglycemia
• Stop insulin if blood glucose <4 mmol/L (72 mg/dL)
• Can repeat >30 minutes after stopping if K+ still >6.5 mmol/L

---

3. Sodium Bicarbonate 4.2% - Shifts K+ into Cells (acts within 1 hour)

• Purpose: Alkalinization causes K+ to shift intracellularly in exchange for H+ ions
• Dose: 1-2 mEq/kg IV over 30-60 minutes
• Onset: Within 1 hour
• Effective even in the absence of acidosis
• Caution:
  • Do NOT give in infants <34 weeks and <3 days of age (rapid administration risks IVH)
  • Avoid if hypocalcemia present (worsens tetany)
  • Not compatible with TPN solutions
  • Combination of albuterol + insulin/dextrose may be more effective

---

4. Salbutamol (Albuterol) Nebulized - Shifts K+ into Cells

• Purpose: Beta-2 agonist stimulates Na+/K+-ATPase pump
• Dose: 0.4 mg/kg nebulized (stat dose x1)
• Onset: Rapid (within 30 minutes)
• Duration: Up to 2 hours
• Side effect: Tachycardia - monitor HR
• Can be combined with insulin/dextrose for additive effect

---

5. Furosemide - Remove K+ from Body

• Dose: 1 mg/kg IV
• Onset: 1-2 hours
• Mechanism: Inhibits Na-K-2Cl cotransporter in thick ascending limb, increasing urinary K+ excretion
• Requires adequate renal function - not effective in oliguria/anuria
• Monitor fluid balance

---

6. Cation Exchange Resins (Sodium Polystyrene Sulfonate / Kayexalate)

• Dose: 1 g/kg PR in NS (0.5 g/mL), minimum retention 30 minutes via rectal tube
• NOT recommended in preterm infants or those with bowel compromise (NEC risk)
• Slow onset; use only as adjunct

---

7. Peritoneal Dialysis / Double Volume Exchange Transfusion

• Reserved for: Refractory hyperkalemia not responding to medical management, or with significant renal failure
• Provides definitive K+ removal

---

Summary Table - Hyperkalemia Management

• NCCC Hyperkalemia Guidelines (2019)

---

PART 2: NEONATAL HYPOKALEMIA

Definition

• Serum K+ <3.5 mmol/L
• Severe: <2.5 mmol/L

Causes

Clinical Features

• Hypotonia, weakness
• Ileus, abdominal distension, constipation
• Cardiac arrhythmias (less common than hyperkalemia in neonates)
• ECG: ST depression, T-wave flattening/inversion, prominent U waves

---

Acute Management of Neonatal Hypokalemia

Step 1: Ensure Urine Output Before Replacing

• Never give IV potassium without confirmed urine output - risk of fatal hyperkalemia

Step 2: Correct Magnesium

• Hypomagnesemia causes refractory hypokalemia (Mg2+ is needed for renal K+ reabsorption)
• Check and correct serum Mg2+ first

Step 3: Determine Route

• Potassium chloride (KCl) oral solution: 1-2 mEq/kg/day in divided doses
• Maximum single enteral dose: ~1 mEq/kg

• Severe hypokalemia (<2.5 mmol/L) or symptomatic (arrhythmia, paralysis)
• Gut not functional (post-surgery, NEC)
• Ongoing high losses

IV Potassium Replacement Doses

Concentration Limits

• Peripheral IV: Maximum 40 mmol/L KCl concentration
• Central line: Up to 80 mmol/L (combined Y-site); some protocols allow up to 60-80 mmol/L
• Solutions >60 mmol/L must be given via central line

Monitoring

• Blood glucose if giving IV fluids with dextrose
• Serum K+ every 4-6 hours during correction
• Stop infusion when K+ >3.5 mmol/L; reduce by 50% at K+ 3.0-3.5 mmol/L
• ECG monitoring mandatory if K+ <3.0 mmol/L or any arrhythmia risk

---

Maintenance Potassium Requirements (Harriet Lane, 23rd ed., p. 648)

Key rule: Do not add potassium to IV fluids in the first 24 hours of life until diuresis is confirmed - risk of hyperkalemia is highest in this window.

---

Key Safety Principles for Any Neonatal Potassium Correction

1. Never give IV potassium as a bolus - always as a controlled infusion
2. Always confirm with non-hemolyzed sample before treating hyperkalemia
3. Confirm urine output before treating hypokalemia
4. Central line required for high-concentration or high-rate infusions
5. ECG monitoring whenever serum K+ is severely abnormal or during rapid correction
6. Acid-base balance matters: alkalosis worsens hypokalemia; acidosis worsens hyperkalemia
7. Correct the cause alongside correcting the electrolyte