Experience | Patient+ | News | Products | Other
This is a PatientPlus article. PatientPlus articles are written for doctors and so the language can be technical, however some people find that they add depth to the patient information leaflets. You may find the abbreviations record helpful.
Micturition Syncope
Post your experienceSee others (32 there)
Syncope results from a reduction of cerebral blood flow. There are many triggers for syncope e.g. coughing and defecation. Micturition syncope occurs when there is temporary loss of consciousness during or after urinating.
More common in males and accounts for 8.4% of all causes of syncope.1 Furthermore 61% of patients with micturition syncope also experience other kinds of syncope.1 Peak age of presentation is 30 - 49 years.
- The underlying cause of micturition syncope is thought to be related to vasovagal syncope with hypotension and possibly bradycardia.2 This may involve postural hypotension and increased vagal tone as a result from straining (valsalva manoeuvre).
- However, the trigger of the vasovagal response is unclear. It has been hypothesised that the bladder becomes hyper-reflexic. This is supported by spinal cord injury patients who develop hypotension and syncope when intermittent urinary catheterisation is performed.3
- Furthermore, the risk of developing hypotension is enhanced by any hypotensive medication e.g. alpha blockers and even antidepressants.
- Excess ethanol intake and excess warmth are also precipitating factors for micturition syncope. Again it is thought that these lead to hypotension.
- Furthermore research in patients with multiple system atrophy, who have frequent pre-syncope and syncope on micturition, reported that during bladder filling they experienced a slight rise in blood pressure with no change in heart rate (both increased in controls).4 This is thought to result from activation of the sympathetic nervous system. In controls at the beginning of micturition this sympathetic activity increased with a further rise in blood pressure and heart rate. Following this there is a decrease in blood pressure and heart rate (back to baseline). Patients with multiple system atrophy showed a similar pattern but with less of an increase in blood pressure at the beginning of urination followed by a fall during micturition. However, the fall is more marked and the duration is longer in multiple system atrophy.4 These changes are dissimilar to those seen in neurally mediated syncope.
Feeling dizzy, lightheaded or short-lived loss of consciousness when passing urine or straight afterwards. A collateral history is vital.
Other causes of syncope e.g.
- Cardiac arrhythmias
- Structural heart disease e.g. aortic stenosis, hypertrophic cardiomyopathy
- Hypovolaemia
- Postural hypotension
These are mostly directed towards excluding other more sinister causes e.g. Holter monitoring, lying and standing blood pressures. Tilt table testing can be used to determine the extent of the autonomic instability and training to desensitise.
- Safety measures - e.g. stand up slowly from a lying position, keep bathroom door open, move sharp objects away.
- Stop any precipitating medications e.g. antihypertensive medication (if possible - especially alpha blockers), antidepressants with hypotensive side effects.
- Botulinum A toxin injections have been injected in to the detrusor muscle of the bladder of patients with spinal cord injuries with some success.3,5
- Fludrocortisone has been used and enhances blood pressure on standing - its role in micturition syncope has not been established.
- Drugs such as SSRI's have been suggested but there no evidence of their benefit and they can also aggravate hypotension.
Document references
- Schiavone A, Biasi MT, Buonomo C, et al; Micturition syncopes. Funct Neurol. 1991 Jul-Sep;6(3):305-8. [abstract]
- Hainsworth R; Pathophysiology of syncope. Clin Auton Res. 2004 Oct;14 Suppl 1:18-24. [abstract]
- Previnaire JG, Soler JM; Micturition syncope following intermittent catheterisation in a tetraplegic patient. Spinal Cord. 2006 Nov;44(11):695-6. Epub 2006 Feb 7. [abstract]
- Uchiyama T, Sakakibara R, Asahina M, et al; Post-micturitional hypotension in patients with multiple system atrophy. J Neurol Neurosurg Psychiatry. 2005 Feb;76(2):186-90. [abstract]
- Woodhouse JB, Patki P, Patil K, et al; Botulinum toxin and the overactive bladder. Br J Hosp Med (Lond). 2006 Sep;67(9):460-4. [abstract]
DocID: 2455
Document Version: 21
DocRef: bgp734
Last Updated: 8 Dec 2008
Review Date: 8 Dec 2010
The authors and editors of this article are employed to create accurate and up to date content reflecting reliable research evidence, guidance and best clinical practice. They are free from any commercial conflicts of interest. Find out more about updating.
Experience | Patient+ | News | Products | Other
Related pages in Patient UK
Your Experience (^ top of page)
Please add your experience about this condition / medicine
View Patient Experience for 'Micturition Syncope' (32 there)PatientPlus articles related to this topic (^ top of page)
Patient UK Newspaper (^ top of page)
Latest Health News
Related Products (^ top of page)
Medical equipment
Books
Other - Useful resources (^ top of page)
Pictures, diagrams, photos, images, etc.Evidence based medicine
Online textbooks and journals
UK Guidelines
Online Videos
Medline
Other good health sites
Want to search some more? Use the Google Search box below to search our site.
Disclaimer: Patient UK has no control over the content of any external links above. Inclusion does not imply endorsement by Patient UK.
Want to advertise on this site? Find out how >>
Here you can follow a link to view existing patient experiences on this subject, or to add your own
This will offer you the usual PDF options i.e. document navigation, search, zoom and formatted print
Note: this is the best way to print the document
Note: this will open in a new window
Note: this will open in a new window
Here you can follow a link to view existing patient experiences on this subject, or to add your own
This will offer you the usual PDF options i.e. document navigation, search, zoom and formatted print
Note: this is the best way to print the document
Note: this will open in a new window
Note: this will open in a new window


