Friday, 29 November 2013

Fainting (Syncope) - Causes and risk factors

Fainting also known as Syncope of "black out" is defined as a condition of sudden loss of consciousness followed by the return to full wakefulness in a short duration as a result of  abnormally low blood pressure. In most cases, it is caused by hypotension, with blood pressure that's lower than 90/60 mmHg.(1). Even though Low blood pressure has mainly been regarded as good health for people who exercise, but recent studies have indicated an association with depression in elderly people. there are epidemiological evidence for an association of low blood pressure with anxiety and depression, which is not caused by cardiovascular disease.(2). In some case, severely low blood pressure can seriously impair adequate blood flow to vital organs and a life-threatening condition called shock.
Causes and risk factors
Causes of fainting may be a result of your heart rate and blood vessels can't react fast enough when your body's need for oxygen changes
1. History of any cardiovascular disease and and cardiac arrhythmias
 In  a study of consecutive patients evaluated for syncope from 1996 through 1998 at an academic medical center, we documented causes, clinical characteristics, and recurrence of syncope while driving. Of 3877 patients identified, 381 (9.8%) had syncope while driving (driving group). Compared with the 3496 patients (90.2%) who did not have syncope while driving, the driving group was younger (P=0.01) and had higher percentages of male patients (P<0.001) and patients with a history of any cardiovascular disease (P=0.01) and stroke (P=0.02). Syncope while driving was commonly caused by neurally mediated syncope (37.3%) and cardiac arrhythmias (11.8%). Long-term survival in the driving group was comparable to that of an age- and sex-matched cohort from the Minnesota population (P=0.15). Among the driving group, syncope recurred in 72 patients, 35 of whom (48.6%) had recurrence >6 months after the initial evaluation. Recurrences during driving happened in 10 patients in the driving group, 7 of which (70%) were >12 months after the initial evaluation.(4)

2. Low blood pressure 
researchers suggested that Syncope due to orthostatic hypotension (OH) refers to loss of consciousness caused by hypotension induced by the upright position; it is an important risk factor for fall-related physical injuries, especially in the elderly adults(5). Other report indicated that eventhough Low blood pressure has mainly been regarded as good health for people who exercise, but recent studies have indicated an association with depression in elderly people. there are epidemiological evidence for an association of low blood pressure with anxiety and depression, which is not caused by cardiovascular disease.

3.  Parkinson's disease and neurological comorbidity in olders
Low blood pressure is considered as a major cause of fainting of patient older than 65 years as a result of  Parkinson's disease and neurological comorbidity. (5)

4.  Medication
there is a report that in patients with AD treated with donepezil, a noninvasive evaluation identified a probable cause of syncope in over two-thirds of patients. Cardiovascular abnormalities were predominant. Noninvasive evaluation is recommended before discontinuing treatment with cholinesterase inhibitors in patients with AD and unexplained syncope.(6)

5. Hemodynamic ischemia 
There a report that a patient with convulsive syncope whose convulsive movements seemed to be associated with transient hemodynamic ischemia in the basal ganglia. In Single-photon emission computed tomography (SPECT, a significant decrease in blood flow was revealed in the anterior part of the left basal ganglia, bilateral frontal areas, and right cerebellar hemisphere. An alteration in the functional balance between the basal ganglia and the cerebral cortices may play a role in the generation of convulsive movements in patients with convulsive syncope.(7)

6. Vertebrobasilar disease
Vertebrobasilar disease is a broad classification describing the condition where there is an insufficient delivery of blood flow via the vertebral and/or basilar arteries to the brain.(8)

7. Vasovagal (situational) syncope
A vasovagal episode or vasovagal response or vasovagal attack (also called neurocardiogenic syncope) is a malaise mediated by the vagus nerve. When it leads to syncope or "fainting", it is called a vasovagal syncope, which is the most common type of fainting(9)

8. Deglutition syncope 
Deglutition suncope is defined as a  loss of consciousness on swallowing. There are report that a 49-year-old woman was referred to the ENT department with a 1.5-year history of dysphagia accompanied by globus sensation and regurgitation as well as recurrent syncopal attacks associated with swallowing solid foods(10) and a case of swallow syncope associated with cold beverage ingestion(11) and a woman who faints when she eats and drinks(12) may be as a result of an ambulatory electrocardiogram revealed atrial and ventricular asystoles immediately after swallowing (13)

9. Cardiac syncope
Structural cardiac abnormalities may cause syncope include cardiac obstructions, pulmonary hypertension, and myocardiopathy. Children with congenital heart disease who experienced syncope should always be referred to a specialist. Primary arrhythmias which are easily diagnosed on ECG are complete atrio-ventricular block and Wolff-Parkinson-White syndrome. "Channelopathies" such as the long OT syndrome and catecholaminergic ventricular tachycardia are increasingly recognized in children, carry a high risk of sudden death and deserve a complete work up, including familial screening and lifelong treatment with beta-blockers(14)

10. History of diaphoresis In the investigation of   whether the pattern of presyncopal prodromal symptoms can predict the recurrence probability of vasovagal syncope, fifty-four patients (68.4%) reported at least one of the four main prodromal symptoms. Median syncopal +/- presyncopal spells were 4 episodes. Forty-two patients (53.2%) experienced recurrence of syncope or presyncope during the follow-up period. In recurrent symptomatic patients, diaphoresis had been more significantly reported in their past medical history (p = 0.018) and they had more syncopal spells before TTT (p = 0.001). Age, gender and type of TTT response did not have any effect on the recurrence of VVS.(15)

11.  Prolonged exercise
Some researchers suggested that the magnitude of exercise-induced hypotension (post-exercise hypotension; PEH), and the hypotensive response to postural change (initial orthostatic hypotension; IOH) are predictors of syncope post-exercise, but research team from the University of Otago, found that endurance athletes who present with greater hypotension are not necessarily at a greater risk of syncope than those who present with lesser reductions in BP.(16)

12.  Chiari type I malformation (CMI)
Chiari type I malformation (CMI) is a congenital hindbrain anomaly characterized by downward displacement of the cerebellar tonsils through the foramen magnum. Chiari type I malformation often presents with a complex clinical picture and can be sporadic or linked to a variety of genetic conditions. (17)

13. Low blood sugar
In the study of Syncope and Hypoglycemia posted in International Journal of Clinical Medicine, 2011, 2, 129-132 doi:10.4236/ijcm.2011.22023 Published Online May 201, showed that hypoglycemic syncope should be sus-pected in older diabetic patients with preserved postural tone, usually but not always using insulin therapy, who show a slow recovery from transient loss of consciousness with persisting neurological impairment and low blood glucose levels.(18)

14. Dehydration 
Dehydration  is defined as a condition of  the excessive loss of body fluid. of which can lead to symptoms of decreased blood pressure (hypotension), and dizziness or fainting(19)

15. Family history
In the study conducted by Johns Hopkins Bloomberg School of Public Health, researchers showed that family history of fainting is not a risk factor for adult-onset NMH in fatigued veterans. Our findings may differ from other studies of familial aggregation in NMH because of study methods or because NMH-fatiguers may differ from NMH-fainters.(20)

16. Pregnancy
A 23-year-old woman at 34 weeks' gestation developed recurrent syncope due to profound sinus arrest captured on electrocardiography. Syncopal events occurred in the same sitting position. An echocardiogram revealed severe collapse of the inferior vena cava each time the patient changed her posture from a supine to a sitting position, which was related to the syncope.(21)

17. Etc.
Chinese Secrets To Fatty Liver And Obesity Reversal
Use The Revolutionary Findings To Achieve 
Optimal Health And Loose Weight

Super foods Library, Eat Yourself Healthy With The Best of the Best Nature Has to Offer

Back to General health

Back to Kyle J. Norton Home page 

No comments:

Post a comment