Differential Diagnosis

• Single Most Likely Diagnosis
  • Orthostatic Hypotension: This condition is characterized by a sudden drop in blood pressure when standing up, leading to dizziness and lightheadedness. The patient's symptoms of intermittent low blood pressure, dizziness, and feeling "drunk without having alcohol" are consistent with orthostatic hypotension. The patient's use of hormone therapy, particularly estradiol and testosterone, may also contribute to orthostatic hypotension.
• Other Likely Diagnoses
  • Dehydration: The patient's frequent consumption of LaCroix, a low-calorie sparkling water, may lead to dehydration, especially if not balanced with sufficient electrolyte intake. Dehydration can cause dizziness, lightheadedness, and low blood pressure.
  • Hypovolemia: The patient's low blood pressure readings and symptoms of dizziness may be indicative of hypovolemia, a condition characterized by decreased blood volume. This could be due to inadequate fluid intake, excessive fluid loss, or other underlying medical conditions.
  • Adrenal Insufficiency: Although the patient denies any thyroid issues, adrenal insufficiency is a possible cause of low blood pressure, dizziness, and lightheadedness. The patient's hormone therapy regimen may also be relevant to this diagnosis.
• Do Not Miss Diagnoses
  • Cardiac Arrhythmias: Abnormal heart rhythms can cause dizziness, lightheadedness, and low blood pressure. It is essential to rule out cardiac arrhythmias, as they can be life-threatening if left untreated.
  • Autonomic Dysfunction: Conditions such as postural orthostatic tachycardia syndrome (POTS) or autonomic nervous system dysfunction can cause orthostatic hypotension, dizziness, and other symptoms. These conditions can be debilitating and require prompt diagnosis and treatment.
  • Pheochromocytoma: This rare tumor of the adrenal gland can cause episodic low blood pressure, dizziness, and other symptoms. Although unlikely, pheochromocytoma is a potentially life-threatening condition that should not be missed.
• Rare Diagnoses
  • Mitral Valve Prolapse: This condition can cause dizziness, lightheadedness, and low blood pressure, especially if there is significant mitral regurgitation.
  • Dysautonomia: This condition is characterized by dysfunction of the autonomic nervous system, which can cause a range of symptoms, including orthostatic hypotension, dizziness, and lightheadedness.
  • Addison's Disease: This rare endocrine disorder can cause low blood pressure, dizziness, and other symptoms due to adrenal insufficiency. Although unlikely, Addison's disease is a potentially life-threatening condition that requires prompt diagnosis and treatment.