Shock: causes, initial assessment and investigations

Shock may result from a number of distinct disease processes and it is commonly associated with trauma, infection and cardiovascular dysfunction. Shock results in significant morbidity and mortality and is a leading cause of death in hospital patients. In order to improve patient outcomes it is important to recognize shock early, then assess and treat the shocked patient in a systematic way. While the cause of the shocked state is sometimes obvious, in more difficult situations the use of the clinical classification of shock into cardiogenic, obstructive, hypovolaemic or distributive shock can help the clinician to discover the underlying cause of the shock. However, it is important to note that while this is a framework in practice there if often considerable overlap between these different types of shock in clinical practice. After identification of patients in shock, immediate life-saving resuscitation with directed therapy to prevent further deterioration, worsening organ failure and to improve outcome is vital. An ABCDE approach can be a useful systematic way for initial assessment and resuscitation. Basic monitoring should be instituted as soon as possible and in severe or unresponsive shock this should be escalated to invasive monitoring. Immediate generic laboratory, microbiological and radiological tests should be carried out as soon as possible and should include a blood lactate level. Further targeted tests should then be tailored to the history, clinical findings and presumed aetiology of the shocked state. These targeted investigations should help to pin point the specific cause of the shock and guide definitive management.