Selected Topics in Neonatal Neurology

Neonatal Hypoxic Ischemic Encephalopathy (HIE)is brain dysfunction from insufficient Oxygen and blood flow during the birth process. A diagnosis of Neonatal HIE requires evidence of fetal distress to point of compromise, i.e. recurring late decelerations, bradycardia or abruption before delivery and altered neonatal behaviors consistent with brain dysfunction. APGAR score is a guide to need for resuscitation. A poor neurodevelopmental outcome correlates only with a 10 minute APGAR below 3.

Classification of Neonatal Hypoxic Ischemic Encephalopathy (HIE)
(Sarnot and Sarnot, 1976)
  1. Grade I HIE: ( 3.9:1000 births)
    Transient CNS irritability and excitation with hyper-reflexia, tremulousness and high pitched cry, worried look with decrease blink, normal muscle tone, act hungry with weak suck, and mydriasis. Usually clears in 24 to 48 hours. Follow-up studies indicate all infants normal consist with no long term neurologic sequalae.
  2. Grade II HIE: (1.1:1000 births)
    CNS suppression and possible injury producing obtundation with inappropriate alerting (lethargic to agitated stupor), mild hypotonia, 50% have focal and multi-focal seizures, weak moro, very weak to absent suck, and miosis. Infants stabilize and begin to improve in 3 to 5 days. At follow-up 80% are normal.
  3. Grade III HIE: (1.0:1000 births)
    CNS suppression with injury. Stuporous to comatose, flaccid, absent suck and moro, intermittent decerebration and unresponsive pupils. Seizures in transition from Grade II to III or in several days if transitions from III to II. 50% do not survive nursery. Survivors have severe neurologic sequalae with profound retardation, microcephaly and spastic quadraparesis.
Causes of Neonatal Seizures
  • HIE is the #1 cause of neonatal seizures
  • Infection: GroupB Strep, Herpes
  • Hemorrhage: IVH and sub-arachnoid
  • Infarction: Neonatal stroke
  • Metabolic: Hypoglycemia, Hypocalcemia
  • Congenital CNS anomaly - genetic and intrauterine insult
  • Inborn error of metabolism - MSUD, galactosemia, organic acidurias
  • Pyridoxine(B6) Dependency
  • Unknown
Causes of Hypotonia
  • Metabolic: Pompe's and Hurler's Syndrome, Gaucher Disease
  • Genetic: Trisomy 21, Prader-Willi
  • Toxic: Hepatic failure, renal failure, acidosis, hypokalemia, HIE (Grade III)
  • Trauma: Focal - Brachial Plexus Injury and Cervical Spinal Cord injury
  • Drug: Any sedating agent - narcotics, Magnesium, barbiturates,
  • anticonvulsants
  • Infection: Sepsis, Botulism - infants (honey)
  • Neuromuscular: Congenital Myopathy, SMA
  • Central Nervous System: cerebral dysgenesis
Brachial Plexus Injury
  • A. Erb-Duchenne Palsy (Upper Roots)
    • Arm internally rotated at shoulder
    • Pronated at the forearm (waiter's tip)
    • Minimal to no sensory loss
    • Triceps 2/4; BC & BR 0/4
  • B. Klumpke's paralysis (Lower roots)
    • Flexion at elbow, forearm supinated
    • fingers extended, paralysis of hand
    • ulnar sensory loss fingers and forearm
    • Horner's Syndrome with root avulsion