Shock vs.Trauma
Shock has the ability to obstruct our access to some of the deepest aspects of the Self - resulting in difficulties with intimacy, self-esteem, connection to one`s sense of purpose and meaning, and spirituality. Shock is stored in the body and reactivated by events in daily life until it is resolved. It is mediated by unconscious rather than conscious aspects of the personality.
Unlike trauma, it is activated not only by stimuli resembling the original trauma, but also by many apparently unrelated triggers. Where trauma maximizes and hones physiological functioning, shock minimizes and  impairs physiological functioning. Trauma still allows intimacy, while shock blocks intimacy. Emerson`s work in explicating the differences between shock and trauma has made it clear that, along with appropriate psychotherapy protocols for treating shock, the physiological shock response requires treatment or it keeps the individual in a constant state of `red alert` that eventually leads to adrenal fatigue and finally, adrenal exhaustion.
Traumatized individuals have had some sense of control and efficacy while their traumatization is in process - fight or flight are successful to some degree in defending against or ameliorating the effects of the traumatizing
agents. In shock, neither fight nor flight is successful. Overwhelm is what  separates shock from trauma.
(Insights Magazine - B.C. Ass. Of Clinical Counsellors - `Pre- and Peri-natal Shock: Considerations for Psychotherapy` by Claire Winstone, pps. 8-24)

Shock will have major impact on both the psychological and physiological levels, including hormonal production such as adrenals and thyroid. Being in the aforementioned state of "red alert", or hypervigilance, over an extended period of time can have a devastating effect on the adrenals and lead to a state which is now commonly referred to as chronic fatigue.
Dr. Emmerson has also broken down shock into classifications of commission (event) or omission (need). There can be the single incident events such as abortion attempt, an epidural, c-section, physical or sexual abuse, sudden loss etc. or multiple incidents of not having basic needs met, i.e. neglect, indifference, lack of touch or comfort. Damage of this sort will often make it difficult for a person to take in love and compassion when it is healthily available to them. A distrusting belief system can govern a lifetime of unhealthy relationships and potentially self-sabotaging actions.

(Stephen P. King - 2003)