I think,vasovagal syncope is checked by tilt table testing not the orhtostatic hypotension ?Syncope can be classified as
- Neurally-mediated (reflex syncope),
- Secondary to orthostatic hypotension or
- Secondary to cardiac causes.
1. Reflex syncope traditionally refers to a heterogeneous group of conditions in which
cardiovascular reflexes that are normally useful in controlling the circulation become
intermittently inappropriate, in response to a trigger.
2. Orthostatic intolerance syndromes are a common cause of syncope in elderly
population, and are usually secondary to autonomic failure, to the use of vasodilator
drugs or to volume depletion.
3. Arrhythmias are the most common cause of cardiac syncope, but structural
cardiovascular disease can also cause syncope in some circumstances.
Reflex (neurally mediated) syncope may be due to vasovagal syncope, which is mediated by emotional distress such as fear or physical pain. Situational syncope describes syncope that occurs with a fixed event such as micturition, deglutition, exercise induced, and carotid sinus syncope. These causes tend to be more benign and do not predict poor outcomes.
Vasovagal syncope is the most common type in young adults but can occur at any age. It usually occurs in a standing position and is precipitated by fear, emotional stress, or pain (eg, after a needlestick). Autonomic symptoms are predominant. Classically, nausea, diaphoresis, fading or "graying out" of vision, epigastric discomfort, and light-headedness precede syncope by a few minutes. Syncope is thought to occur secondary to efferent vasodepressor reflexes by a number of mechanisms, resulting in decreased peripheral vascular resistance. It is not life threatening and occurs sporadically.
Situational syncope is essentially a reproducible vasovagal syncope with a known precipitant. Micturition, defecation, deglutition, tussive, and carotid sinus syncope are types of situational syncope. These stimuli result in autonomic reflexes with a vasodepressor response, ultimately leading to transient cerebral hypotension. These are not life-threatening but can cause morbidity. The treatment involves avoidance of the precipitant when possible and the initiation of counter maneuvers when anticipated.
Syncope due to orthostatic hypotension can occur through several mechanisms. Pure autonomic failure can be associated with Parkinson's disease or dementia. Secondary autonomic insufficiency can be due to diabetes, uremia, or spinal injury. Drugs such as alcohol cause orthostatic intolerance and medications such as vasodilators and antidepressants block orthostatic reflexes. Volume depletion due to blood loss, vomiting, diarrhea, poor oral intake, and diuretics also cause orthostatic syncope.
Dehydration and decreased intravascular volume contribute to orthostasis. Orthostatic syncope describes a causative relationship between orthostatic hypotension and syncope. Orthostatic hypotension increases in prevalence with age as a blunted baroreceptor response results in failure of compensatory cardioacceleration. In elderly patients, 45% of these cases are related to medications. Limited evidence suggests that polydipsia may reduce recurrences. Orthostasis is a common cause of syncope and tends to be recurrent. Bedside orthostatics cannot exclude this as an etiology; if suspected, patients should be referred to a primary care provider for outpatient tilt-table testing.
Cardiac (cardiopulmonary) syncope may be due to vascular disease, cardiomyopathy, arrhythmia, or valvular dysfunction and predicts a worse short-term and long-term prognosis. Obtaining an initial ECG is mandatory if any of these causes are possible for the differential diagnosis.
I think,vasovagal syncope is checked by tilt table testing not the orhtostatic hypotension ?
The tilt-table test is a simple, noninvasive, and informative test first described in 1986 as a diagnostic tool for patients with syncope of unknown origin.................. tilt-table testing is particularly helpful in confirmation of the etiology of syncope dysfunction of the autonomic nervous system, encompassing primary or secondary dysautonomias, postural orthostatic tachycardia syndrome (POTS), and vasodepressor or vasovagal syncope...............................Consider tilt-table testing in patients with signs or symptoms suggestive of orthostatic hypotension, vasodepressor or vasovagal syncope, postural orthostatic tachycardia, or when other causes of syncope have been eliminated.
Not usuallyDoes situational syncope has also autonomic symptoms before passing out