The acute form can be divided into 3 phases (Dennery et al):
(1) Phase 1: first 1-2 days
(2) Phase 2: remainder of first week
(3) Phase 3: after first week
Clinical findings during the acute encephalopathy:
(1) sensorineural hearing loss
(2) ocular findings ("setting sun" sign, oculogyric crises)
(3) feeble sucking with poor feeding
(4) hypotonia or hypertonia
(5) lethargy or stupor
(6) opisthotonus or decerebrate posturing
(7) seizures
(8) high-pitched cry
(9) incomplete Moro response
(10) hypothermia or hyperthermia (fever)
The mortality rate during the acute phase is about 4% (Dennery et al).
Long-term sequelae (months to lifelong):
(1) sensorineural hearing loss
(2) paresis of upward gaze, nystagmus
(3) delay in motor development
(4) questionable hypotonia
(5) cognitive dysfunction
(6) mental retardation
(7) choreoathetosis, ballismus or tremor
(8) asymmetric spasticity
(9) equivocal Babinski reflex
(10) gait abnormalities
(11) dental dysplasia
