From the Guidelines
If you experience pre-syncope, sit or lie down immediately and elevate your legs if possible to improve blood flow to your brain, as this can help prevent progression to syncope and reduce the risk of injury 1. Pre-syncope is a cognitive state in which one lacks awareness of oneself and one’s situation, with an inability to respond to stimuli, and it is often a precursor to syncope, which is a symptom that presents with an abrupt, transient, complete loss of consciousness, associated with inability to maintain postural tone, with rapid and spontaneous recovery 1. The underlying mechanism of pre-syncope and syncope is presumed to be cerebral hypoperfusion, which can be caused by various factors, including orthostatic hypotension, vasovagal reactions, and cardiac arrhythmias 1. Some key points to consider in the management of pre-syncope include:
- Maintaining or assuming a safe position, such as sitting or lying down, to prevent injury in case of progression to syncope 1
- Using physical counterpressure maneuvers (PCMs) to increase blood pressure and improve symptoms, although this is not recommended if symptoms of a heart attack or stroke are present 1
- Increasing fluid intake to 2-3 liters daily and consuming adequate salt, unless contraindicated by other medical conditions, to help prevent dehydration and orthostatic hypotension 1
- Avoiding triggers such as prolonged standing, hot environments, dehydration, and alcohol, which can exacerbate pre-syncope and syncope 1
- Seeking medical attention if symptoms persist or worsen, as pre-syncope can indicate underlying conditions that require medical evaluation and treatment 1. In terms of medication, fludrocortisone (starting at 0.1mg daily) or midodrine (2.5-10mg three times daily) may be prescribed for recurrent cases of pre-syncope, although the decision to use these medications should be made on a case-by-case basis, taking into account the individual's medical history and underlying conditions 1. Overall, the management of pre-syncope should focus on preventing progression to syncope, reducing the risk of injury, and addressing any underlying conditions that may be contributing to the symptoms.
From the Research
Definition and Causes of Pre-syncope
- Pre-syncope, also known as near-syncope, is a condition that may precede syncope, which is a transient loss of consciousness due to global cerebral hypoperfusion 2.
- The causes of pre-syncope can be similar to those of syncope, including vasovagal or orthostatic origin, and may depend on a reduction of vascular total peripheral resistance and/or cardiac output 3.
Interventions for Pre-syncope
- Physical counter-pressure maneuvers (PCM) may be of benefit during the acute episode preceding syncope (presyncope) 4.
- A systematic review of interventions for presyncope found that PCM may provide benefit for prevention of syncope during acute episodes of presyncope, with a relative risk (RR) of 1.80 [1.26-1.89] in one randomized controlled trial (RCT) 4.
- The use of PCM was also found to improve symptom improvement, with RR of 6.00 [2.21-8.61] and 1.57 [1.06-1.93] in two RCTs, and to improve blood pressure, with a mean difference of 21 mmHg higher systolic blood pressure and 11 mmHg higher diastolic blood pressure 4.
Diagnosis and Management of Pre-syncope
- The diagnosis of pre-syncope is similar to that of syncope, and relies on a thorough history and physical examination, including orthostatic assessment 2.
- Short-term risk assessment should be performed to determine the need for admission, and monitoring is indicated until a diagnosis is made in patients with suspected cardiac syncope 2.
- Outpatient evaluation with tilt-table testing is appropriate for patients with suspected reflex syncope or orthostatic hypotension 2.