Most cases of sudden and temporary loss of
consciousness [syncope] are caused by hypoperfusion of the formatio reticularis. more
rarely by primary neurologic or metabolic disorders. The most common etiology is
vasodepressor (vasovagal) syncope, which is caused by peripheral vasodilation due to acute
withdrawal of the efferent sympathetic tone, while the parasympathetic outpour is
increased at the same time. Although the efferent limb of the baroreflex manifests in a
rather uniform way, the afferent parasympathetic limb is very variable, leading to a
variety of clinical presentations and triggers (orthostatic hypotension, pain, fear,
cough, micturition, emotions). While vasodepressor syncope mainly occurs in young people
with healthy hearts, cardiac syncope caused by arrhythmias or obstructive lesions are more
frequently found in elderly patients with organic heart disease. Neurogenic syncope
comprises either primary neurologic disorders, such as epilepsia, or hypoperfusion of the
vertebrobasilar system (TIA). Rarely, an acute increase of intracerebral pressure may
cause syncope. Similarly, metabolic disorders or side effects of drugs are rare causes of
syncope; however, drugs may act as important cofactors in the pathogenesis of syncope.
MAIN MESH SUBJECTS:
Syncope/*ETIOLOGY/PHYSIOPATHOLOGY
ADDITIONAL MESH SUBJECTS:
Arousal/PHYSIOLOGY
Arrhythmia/COMPLICATIONS/PHYSIOPATHOLOGY
English Abstract
Human
Parasympathetic Nervous System/PHYSIOPATHOLOGY
Reticular Formation/BLOOD SUPPLY
Sympathetic Nervous System/PHYSIOPATHOLOGY
Syncope, Vasovagal/ETIOLOGY/PHYSIOPATHOLOGY
Vertebrobasilar Insufficiency/COMPLICATIONS/PHYSIOPATHOLOGY
PUBLICATION TYPES:
JOURNAL ARTICLE
REVIEW
REVIEW, TUTORIAL
LANGUAGE:
Ger
On Sabbatical!
When my office
lease expired at the end of 2004, I decided to turn it into a
"sabbatical" from my private practice. Many years ago, in my
grandfather's 89th year of life, he told me, "John, it is important
to smell the roses while you can still smell them." His life
gave living a very good reputation. It is also true that the
pursuit of that philosophy required my grandfather to to re-open his
assay office/ore market in Wickenburg, Arizona as a 75-year-old because
he had run a little short of retirement money. Thus, if blessed with his
luck and health, I'll be back.. --jjh
