Neonatal Hypokalemia
Neonatal Hypokalemia
Neonatal hypokalemia is defined as serum potassium level <3.5 mEq/L in term infants and <3.0 mEq/L in preterm infants. It's a critical electrolyte disorder requiring prompt recognition and management.
Key Points
- Severe hypokalemia: K+ <2.5 mEq/L
- Higher risk in premature infants
- Can be life-threatening if untreated
- ECG monitoring essential in severe cases
- Common in infants receiving diuretics
Definition & Epidemiology
Classification
- Mild: 3.0-3.4 mEq/L
- Moderate: 2.5-2.9 mEq/L
- Severe: <2.5 mEq/L
Epidemiology
- Prevalence:
- 10-15% of NICU patients
- Higher in premature infants (20-30%)
- Risk Factors:
- Prematurity
- Diuretic therapy
- Total parenteral nutrition
- Respiratory alkalosis
- Maternal hypertension treatment
- Chronic lung disease
Pathophysiology & Etiology
Mechanisms of Hypokalemia
- Decreased intake:
- Inadequate K+ supplementation
- Poor enteral feeding
- TPN-related deficiency
- Increased losses:
- Renal losses:
- Diuretic therapy
- Tubular disorders
- Mineralocorticoid excess
- Gastrointestinal losses:
- Vomiting
- Diarrhea
- Nasogastric drainage
- Renal losses:
- Transcellular shifts:
- Respiratory alkalosis
- Beta-agonist therapy
- Insulin therapy
Associated Conditions
- Primary disorders:
- Bartter syndrome
- Gitelman syndrome
- Cystic fibrosis
- Secondary disorders:
- Chronic lung disease
- Congestive heart failure
- Renal tubular acidosis
Diagnosis & Clinical Features
Clinical Manifestations
- Cardiovascular:
- Arrhythmias
- Hypotension
- ECG changes:
- Flattened T waves
- ST depression
- U waves
- Prolonged QT interval
- Neuromuscular:
- Hypotonia
- Lethargy
- Poor feeding
- Respiratory muscle weakness
- Metabolic:
- Glucose intolerance
- Metabolic alkalosis
Diagnostic Workup
- Essential laboratory tests:
- Serum electrolytes
- Blood gases
- Magnesium levels
- Calcium levels
- Urinary potassium
- Transtubular potassium gradient (TTKG)
- Cardiac evaluation:
- 12-lead ECG
- Continuous cardiac monitoring
Management
General Principles
- Assessment:
- Severity of hypokalemia
- Presence of symptoms
- ECG changes
- Underlying cause
- Monitoring requirements:
- Continuous cardiac monitoring
- Frequent K+ measurements
- Fluid balance
- Associated electrolytes
Treatment Strategies
- Maximum concentration: 40 mEq/L
- Maximum rate: 0.5-1.0 mEq/kg/hour
- Continuous cardiac monitoring
- Oral/enteral supplementation if possible
- IV replacement if symptomatic
- Regular monitoring
- Oral supplementation
- Dietary modification
- Treatment of underlying cause
Potassium Replacement Calculations
- K+ deficit (mEq) = (Desired K+ - Current K+) × Weight (kg) × 0.4
- Consider magnesium replacement if concurrent hypomagnesemia
Complications & Monitoring
Potential Complications
- Cardiac:
- Life-threatening arrhythmias
- Cardiac arrest
- Poor cardiac contractility
- Respiratory:
- Respiratory failure
- Need for ventilatory support
- Treatment-related:
- Hyperkalemia from over-correction
- Tissue necrosis from IV infiltration
- Cardiac conduction abnormalities
Monitoring Parameters
- Clinical monitoring:
- Vital signs
- Neurological status
- Feeding tolerance
- Urine output
- Laboratory monitoring:
- Serum K+ levels
- Other electrolytes
- Acid-base status
- Renal function
- Cardiac monitoring:
- Continuous ECG
- Blood pressure
- Heart rate variability
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
