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Evaluation of and initial approach to the adult patient with undifferentiated hypotension and shock

David F Gaieski, MD
Mark E Mikkelsen, MD, MSCE
Section Editors
Polly E Parsons, MD
Robert S Hockberger, MD, FACEP
Deputy Editor
Geraldine Finlay, MD


Shock is a life-threatening condition of circulatory failure that most commonly presents with hypotension. It can also be heralded by other vital sign changes or the presence of elevated serum lactate levels. The effects of shock are initially reversible but can rapidly become irreversible, resulting in multi-organ failure (MOF) and death. Thus, when a patient presents with undifferentiated hypotension and/or is suspected of having shock, it is important that the clinician rapidly identify the etiology so that appropriate therapy can be administered to prevent MOF and death [1,2].

This topic reviews the clinical presentation as well as the initial diagnostic and therapeutic approaches to the adult patient with hypotension and suspected shock of unknown etiology (ie, undifferentiated shock). The definition, classification, etiology, and pathophysiology of shock are discussed separately. (See "Definition, classification, etiology, and pathophysiology of shock in adults".)


Shock is defined as a state of cellular and tissue hypoxia due to reduced oxygen delivery and/or increased oxygen consumption or inadequate oxygen utilization. This most commonly occurs when there is circulatory failure manifest as hypotension (ie, reduced tissue perfusion). “Undifferentiated shock” refers to the situation where shock is recognized, but the cause is unclear.

While patients often have a combination of more than one form of shock (multifactorial shock), four classes of shock are recognized (table 1):

Distributive (eg, septic shock, systemic inflammatory response syndrome, neurogenic shock, anaphylactic shock, toxic shock, end-stage liver disease, endocrine shock)


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Literature review current through: Sep 2016. | This topic last updated: May 26, 2016.
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