What is the cause of micturitional (urinary) syncope?

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From the Guidelines

Micturitional syncope is best managed by preventive measures, including sitting while urinating, avoiding alcohol, staying hydrated, and changing positions slowly, as these methods can help reduce the risk of fainting and improve quality of life. This condition is a type of situational syncope, which is a reflex syncope associated with a specific action, such as urination 1. According to the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope, situational syncope is a form of reflex syncope that occurs in response to specific physical functions, including micturition 1. The guideline defines reflex syncope as a condition caused by a reflex that leads to vasodilation, bradycardia, or both 1.

The pathophysiology of micturitional syncope involves a sudden drop in blood pressure caused by the vasovagal reflex, which is triggered by the relaxation of the bladder muscles 1. This can lead to a reduction in blood flow to the brain, resulting in fainting or lightheadedness. To prevent episodes of micturitional syncope, individuals should:

  • Sit rather than stand while urinating, especially at night or when feeling unwell
  • Avoid alcohol consumption
  • Stay hydrated
  • Change positions slowly (from lying to sitting to standing)

For those with recurrent episodes, medical evaluation is recommended as it may indicate underlying cardiovascular issues 1. Treatment typically focuses on preventive measures rather than medications, though in severe cases, doctors might prescribe medications that help regulate blood pressure 1. The European Heart Journal guidelines on management of syncope also list micturition as a cause of situational syncope 1.

Overall, preventive measures are the most effective way to manage micturitional syncope and improve quality of life, as they can help reduce the risk of fainting and related complications 1.

From the Research

Definition and Prevalence of Micturitional Syncope

  • Micturition syncope is a transient loss of consciousness with onset immediately before, during, or after micturition 2.
  • It accounts for 8.39% of the total number of syncopes and is prevalent among men in the 50 and 60 year age groups 3.
  • Literature evidence indicates that healthy young men are a population with major risk for presenting micturition syncope, with a peak of incidence around 40 to 50 years of age 2.

Clinical Presentation

  • Micturition syncope usually occurs in the morning, after wake-up, or, more generally, when the male patients assume the orthostatic position after a period of supine position in a warm bed 2.
  • In pediatric patients, the syncope has been presented in the same conditions: in the morning; after wake-up; in an orthostatic position; just before, after, or during urinary bladder voiding; and with spontaneous recovery in few minutes 2.
  • Patients with micturition syncope may also exhibit other kinds of syncope, with 61% of patients experiencing vasovagal reaction during the vegetative activation tests more often than patients exclusively with micturition syncope 3.

Relationship to Orthostatic Hypotension

  • Orthostatic hypotension is a condition that can cause syncope, and it is often associated with autonomic failure 4, 5.
  • However, the cardiovascular vegetative nervous system is unaffected in patients with micturition syncope 3.
  • Midodrine has been proposed in the management of patients with orthostatic hypotension and recurrent reflex syncope, and it has been shown to improve clinical important outcomes in these patients 6.

Diagnosis and Management

  • In pediatric patients, all investigations made as the first approach in the pediatric emergency department may not show any abnormal results, possibly underlying the syncope episodes 2.
  • Clinicians should be aware of the clinical presentation of micturition syncope to recognize and manage it easily in children 2.
  • A combination of fludrocortisone, a pressor agent (midodrine or droxidopa), supplemented with procedures to improve orthostatic defenses during periods of increased orthostatic stress, may be used to treat orthostatic hypotension 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Micturition syncopes.

Functional neurology, 1991

Research

Treatment of orthostatic hypotension.

Seminars in neurology, 2003

Research

Orthostatic Hypotension: Mechanisms, Causes, Management.

Journal of clinical neurology (Seoul, Korea), 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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