Clinical meaning
Hypoxic-Ischemic Encephalopathy occurs in two phases. Primary injury: ATP depletion leads to failure of Na/K ATPase, intracellular calcium influx, and excitotoxic glutamate release. Latent period (6-hour therapeutic window): partial energy recovery. Secondary injury: mitochondrial failure, ROS production, inflammation (IL-1beta, TNF-alpha), and apoptosis via caspase activation. Therapeutic hypothermia (33.5C for 72 hours) reduces metabolic rate by 5% per degree, decreases excitotoxicity, and inhibits apoptotic pathways.
Diagnosis & workup
Diagnostics & workup: - Order amplitude-integrated EEG (aEEG) for seizure detection and severity staging - Order MRI brain at 3-5 days of life (basal ganglia/thalami or watershed pattern) - Order cord blood gases (pH < 7.0, base deficit > 12 confirms asphyxia) - Order LFTs, renal function, cardiac enzymes for multi-organ dysfunction - Order continuous EEG for subclinical seizure monitoring - Order cranial ultrasound as bedside screening tool - Order coagulation studies (DIC risk from tissue injury) - Apply Sarnat staging for severity classification and treatment eligibility