Syncope
Syncope is a "transient loss of consciousness and postural tone caused by diminished blood flow to the brain (i.e., brain ischemia). Presyncope refers to the sensation of lightheadedness and loss of strength that precedes a syncopal event or accompanies an incomplete syncope."[1]
Diagnosis
History and physical
An evaluation based on the initial history and physical examination will correctly diagnose the underlying cause in 63% of patients according to one case series.[2]
Having no warning symptoms suggests a cardiac arrhythmia.[3] Having more than one prodrome symptom (e.g. dizzines, nausea) is predictive of vasovagal and psychogenic syncope.[4]
Regarding the physical exam, testing or carotid sinus hypersensitivity may be best done with the patients standing.[5]
Testing
A p-wave longer than 120 ms on electrocardiogram is suggestive of a cardiac arrhythmia.[4]
Evaluation of the carotid arteries is mainly helpful if there are focal neurological findings.[6]
Prognosis
The San Francisco Syncope Rule (online) can predict the chance of serious events within seven days.[7] When internally validated, its sensitivity was 98%.[7] However, indpendent, external validations have yielded sensitivities of 89%[8] and 74%[9].
References
- ↑ Anonymous (2024), Syncope (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ van Dijk N, Boer KR, Colman N, et al (2008). "High diagnostic yield and accuracy of history, physical examination, and ECG in patients with transient loss of consciousness in FAST: the Fainting Assessment study". J. Cardiovasc. Electrophysiol. 19 (1): 48–55. DOI:10.1111/j.1540-8167.2007.00984.x. PMID 17916139. Research Blogging.
- ↑ Krahn AD, Klein GJ, Yee R, Skanes AC (May 2001). "Predictive value of presyncope in patients monitored for assessment of syncope". Am. Heart J. 141 (5): 817–21. DOI:10.1067/mhj.2001.114196. PMID 11320372. Research Blogging.
- ↑ 4.0 4.1 Graf D, Schlaepfer J, Gollut E, et al (2008). "Predictive models of syncope causes in an outpatient clinic". Int. J. Cardiol. 123 (3): 249–56. DOI:10.1016/j.ijcard.2006.12.007. PMID 17397948. Research Blogging.
- ↑ Parry SW, Richardson DA, O'Shea D, Sen B, Kenny RA (2000). "Diagnosis of carotid sinus hypersensitivity in older adults: carotid sinus massage in the upright position is essential". Heart 83 (1): 22–3. PMID 10618329. [e]
- ↑ Schnipper JL, Ackerman RH, Krier JB, Honour M (April 2005). "Diagnostic yield and utility of neurovascular ultrasonography in the evaluation of patients with syncope". Mayo Clin. Proc. 80 (4): 480–8. PMID 15819284. [e]
- ↑ 7.0 7.1 Quinn J, McDermott D, Stiell I, Kohn M, Wells G (May 2006). "Prospective validation of the San Francisco Syncope Rule to predict patients with serious outcomes". Ann Emerg Med 47 (5): 448–54. DOI:10.1016/j.annemergmed.2005.11.019. PMID 16631985. Research Blogging.
- ↑ Sun BC, Mangione CM, Merchant G, et al (April 2007). "External validation of the San Francisco Syncope Rule". Ann Emerg Med 49 (4): 420–7, 427.e1–4. DOI:10.1016/j.annemergmed.2006.11.012. PMID 17210201. Research Blogging.
- ↑ Birnbaum A, Esses D, Bijur P, Wollowitz A, Gallagher EJ (February 2008). "Failure to Validate the San Francisco Syncope Rule in an Independent Emergency Department Population". Ann Emerg Med. DOI:10.1016/j.annemergmed.2007.12.007. PMID 18282636. Research Blogging.