Evaluation and Management of Acute Transient Loss of Consciousness

Transient loss of consciousness (TLOC) is among the most common complaints encountered by clinicians across specialties. Possible etiologies of acute TLOC can be classified as neurologic, systemic, and functional. Neurologic causes occur due to a primary dysfunction of the neuronal circuitry that maintains awareness, as seen in epileptic seizures. Systemic conditions affect consciousness through global cerebral dysfunction or hypoperfusion with subsequent loss of postural tone through varied mechanisms such as hypoxia, hypoglycemia, and neurocardiogenic syncope. Functional neurologic disorders (also known as conversion disorders or psychogenic spells) refer to clinical conditions in which clinical presentation can mimic but does not completely fit with any specific neurologic or systemic disorder and conventional diagnostic testing reveals normal neurologic and systemic structures. The focus of this review will be on the diagnostic process and tools to differentiate between the multitudes of causes of TLOC.