Differential Diagnosis for Dizziness with Standing

Single Most Likely Diagnosis

• Orthostatic Hypotension: This condition is characterized by a significant drop in blood pressure when standing up, leading to dizziness. It is a common cause of dizziness with standing, especially in the elderly or those with dehydration, medication side effects, or autonomic dysfunction.

Other Likely Diagnoses

• Dehydration: Inadequate fluid intake or excessive fluid loss can lead to dehydration, causing dizziness upon standing due to decreased blood volume and subsequent drop in blood pressure.
• Anemia: Low red blood cell count or hemoglobin can reduce oxygen delivery to tissues, including the brain, leading to dizziness when standing.
• Hypoglycemia: Low blood sugar can cause dizziness, sweating, and fainting, especially when standing, due to inadequate glucose supply to the brain.
• Vasovagal Syncope: A common cause of fainting spells, often triggered by standing for long periods, stress, or medical procedures, leading to a temporary loss of consciousness.

Do Not Miss Diagnoses

• Cardiac Arrhythmias: Abnormal heart rhythms, such as atrial fibrillation or ventricular tachycardia, can lead to dizziness or fainting when standing due to inadequate cardiac output.
• Pulmonary Embolism: A blood clot in the lungs can cause sudden dizziness, shortness of breath, and fainting, especially when standing, due to decreased oxygenation and cardiac output.
• Aortic Stenosis: Severe narrowing of the aortic valve can lead to dizziness, fainting, or chest pain when standing, due to reduced cardiac output and increased pressure gradient across the valve.
• Subclavian Steal Syndrome: A rare condition where the subclavian artery is narrowed or blocked, leading to reversed blood flow in the vertebral artery, causing dizziness, fainting, or syncope when standing.

Rare Diagnoses

• Postural Orthostatic Tachycardia Syndrome (POTS): A condition characterized by excessive heart rate increase when standing, often accompanied by dizziness, nausea, and other symptoms.
• Autonomic Dysfunction: Disorders affecting the autonomic nervous system, such as multiple system atrophy or pure autonomic failure, can cause dizziness, fainting, or orthostatic hypotension when standing.
• Chiari Malformation: A rare congenital condition where the cerebellum extends into the spinal canal, potentially causing dizziness, fainting, or neurological symptoms when standing.