[1] Ditunno et al. proposed a four-phase model for spinal shock in 2004 as follows:[2] Phase 1 is characterized by a complete loss—or weakening—of all reflexes below the SCI.
The neurons involved in various reflex arcs normally receive a basal level of excitatory stimulation from the brain.
Phase 4 on the other hand, is soma-mediated, and will take longer for the soma to transport various growth factors, including proteins, to the end of the axon.
[3] In spinal cord injuries above T6, neurogenic shock may occur, from the loss of autonomic innervation from the brain.
Cervical lesions cause total loss of sympathetic innervation and lead to vasovagal hypotension and bradyarrhythmias – which resolve in 3–6 weeks.