Differential Diagnosis of Presyncope in a 57-year-old Female

Single Most Likely Diagnosis

• Vasovagal Syncope: This is the most common cause of syncope in adults, often triggered by stress, pain, or prolonged standing. It is characterized by a sudden drop in heart rate and blood pressure, leading to reduced blood flow to the brain.

Other Likely Diagnoses

• Orthostatic Hypotension: A drop in blood pressure upon standing, which can be due to dehydration, medication side effects, or autonomic nervous system dysfunction.
• Cardiac Arrhythmias: Conditions like atrial fibrillation or supraventricular tachycardia can lead to presyncope by disrupting normal heart rhythm and reducing cardiac output.
• Hypovolemia: Dehydration or significant blood loss can cause a decrease in blood volume, leading to reduced blood pressure and presyncope.

Do Not Miss Diagnoses

• Myocardial Infarction: Although less common, a heart attack can present with presyncope, especially in women, who may not always exhibit typical chest pain symptoms.
• Pulmonary Embolism: A blockage in one of the arteries in the lungs can lead to sudden onset of presyncope due to the acute increase in pulmonary vascular resistance.
• Aortic Dissection: A tear in the inner layer of the aorta can cause severe pain and presyncope due to compromised blood flow.
• Subarachnoid Hemorrhage: Bleeding into the space surrounding the brain can cause sudden, severe headache and presyncope.

Rare Diagnoses

• Adrenal Insufficiency: A condition where the adrenal glands do not produce adequate amounts of hormones, potentially leading to hypotension and presyncope.
• Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodes of high blood pressure, leading to presyncope.
• Subclavian Steal Syndrome: A condition where there is a significant stenosis or occlusion of the subclavian artery, leading to reversal of blood flow in the vertebral artery and potential presyncope.

Each of these diagnoses has a distinct set of risk factors, symptoms, and diagnostic approaches. A thorough medical history, physical examination, and appropriate diagnostic tests are crucial for determining the underlying cause of presyncope in this patient.