Differential Diagnosis for Presyncope
Single Most Likely Diagnosis
- Vasovagal Syncope: This is the most common cause of presyncope, often triggered by stress, pain, or prolonged standing, leading to a sudden drop in blood pressure and heart rate.
Other Likely Diagnoses
- Dehydration: Inadequate fluid intake or excessive fluid loss can lead to hypovolemia, causing a decrease in blood pressure and potentially resulting in presyncope.
- Orthostatic Hypotension: A sudden drop in blood pressure when standing up from sitting or lying down, often seen in patients with autonomic dysfunction or those taking certain medications.
- Anxiety or Panic Disorder: Intense anxiety or panic can lead to hyperventilation, causing respiratory alkalosis and potentially resulting in presyncope.
Do Not Miss Diagnoses
- Cardiac Arrhythmias: Conditions such as atrial fibrillation, ventricular tachycardia, or bradycardia can lead to presyncope due to inadequate cardiac output.
- Myocardial Infarction or Cardiac Ischemia: Reduced blood flow to the heart muscle can cause presyncope, especially in patients with pre-existing coronary artery disease.
- Pulmonary Embolism: A blockage in the lungs' blood vessels can lead to presyncope due to decreased oxygenation and cardiac output.
- Aortic Dissection or Rupture: A tear in the aorta's wall can cause presyncope due to severe pain, hypotension, and decreased cardiac output.
Rare Diagnoses
- Subclavian Steal Syndrome: A rare condition where the subclavian artery is narrowed or blocked, leading to decreased blood flow to the brain and potentially causing presyncope.
- Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodic hypertension, leading to presyncope.
- Hypoglycemia: Low blood sugar can cause presyncope, especially in patients with diabetes or those taking certain medications.
- Multiple System Atrophy: A rare neurodegenerative disorder that can cause autonomic dysfunction, leading to presyncope.