Sarnat and Sarnat classified neonatal encephalopathy following fetal distress in near and full-term infants. The authors are from St. Louis University and Cardinal Glennon Memorial Hospital for Children.
Parameters:
(1) level of consciousness
(2) muscle tone
(3) posture
(4) stretch reflexes
(5) segmental myoclonus
(6) suck reflex
(7) Moro response
(8) oculovestibular reflex
(9) tonic neck reflex
(10) autonomic system function
(11) pupillary reaction
(12) heart rate
(13) bronchial and salivary secretions
(14) gastrointestinal motility
(15) seizure activity
(16) electroencephalographic (EEG) features
|
Parameter |
Stage 1 |
Stage 2 |
Stage 3 |
|
consciousness |
hyperalert |
lethargic, obtunded |
stuporous or comatose |
|
muscle tone |
normal |
mild hypotonia |
flaccid |
|
posture |
mild distal flexion |
strong distal flexion |
intermittent decerebration |
|
stretch reflexes |
overactive |
overactive |
decreased or absent |
|
segmental myoclonus |
present |
present |
absent |
|
suck reflex |
weak |
weak or absent |
absent |
|
Moro response |
strong with low threshold |
weak with high threshold |
absent |
|
oculovestibular |
normal |
overactive |
weak or absent |
|
tonic neck |
slight |
strong |
absent |
|
autonomic system |
sympathetic |
parasympathetic |
both depressed |
|
pupils |
mydriasis |
miosis |
often unequal, poor light response |
|
heart rate |
tachycardia |
bradycardia |
variable |
|
secretions |
sparse |
profuse |
variable |
|
GI motility |
normal or decreased |
increased, including diarrhea |
variable |
|
seizure activity |
none |
focal or multifocal |
uncommon |
|
EEG |
normal |
low voltage continuous delta and theta waves (early), periodic pattern (later); seizure activity |
periodic pattern with isopotential phases (early) followed by totally isopotential |
where:
• Note the lack of seizure activity in Stage 3.
|
Stage |
Duration |
|
Stage 1 |
tends to resolve within 24 hour |
|
Stage 2 |
tends to last 2-14 days |
|
Stage 3 |
highly variable and may last for weeks |
Risk factors for later neurologic impairment:
(1) Stage 3
(2) Stage 2 for 7 days or more
(3) Stage 2 with failure of EEG to revert to normal
Specialty: Neurology, Pedatrics
