Differential Diagnosis for Lightheadedness

Single Most Likely Diagnosis

• Orthostatic Hypotension: This is often the most common cause of lightheadedness, particularly in the elderly or those with dehydration, medication side effects, or autonomic dysfunction. It occurs when there's a significant drop in blood pressure upon standing, leading to reduced blood flow to the brain.

Other Likely Diagnoses

• Dehydration: Lack of fluids can lead to a decrease in blood volume, reducing blood flow to the brain and causing lightheadedness.
• Anxiety or Panic Attacks: These conditions can cause lightheadedness due to hyperventilation, which leads to a decrease in carbon dioxide levels in the blood, affecting blood pH and causing dizziness.
• Hyperventilation Syndrome: Similar to anxiety or panic attacks, hyperventilation can lead to respiratory alkalosis, causing lightheadedness.
• Vasovagal Syncope: A common cause of fainting spells, often triggered by stress, pain, or prolonged standing, leading to a sudden drop in heart rate and blood pressure.

Do Not Miss Diagnoses

• Cardiac Arrhythmias: Conditions like atrial fibrillation or other arrhythmias can lead to reduced cardiac output, causing lightheadedness. Missing these diagnoses can be fatal.
• Myocardial Infarction or Cardiac Ischemia: Although less common, chest pain accompanied by lightheadedness could indicate a heart attack or ischemia, which requires immediate medical attention.
• Stroke or Transient Ischemic Attack (TIA): While less typical, lightheadedness can be a symptom of a stroke or TIA, especially if accompanied by other neurological deficits.
• Severe Anemia: Significant blood loss or severe anemia can lead to reduced oxygen delivery to the brain, causing lightheadedness.

Rare Diagnoses

• Multiple System Atrophy: A rare neurodegenerative disorder that can cause autonomic dysfunction, leading to orthostatic hypotension and lightheadedness.
• Postural Orthostatic Tachycardia Syndrome (POTS): Characterized by an excessive heart rate increase upon standing, often accompanied by lightheadedness.
• Inner Ear Disorders: Conditions like benign paroxysmal positional vertigo (BPPV) or Meniere's disease can cause vertigo, which may be described as lightheadedness.
• Adrenal Insufficiency: Rarely, adrenal gland disorders can lead to orthostatic hypotension and lightheadedness due to inadequate cortisol and aldosterone production.