Differential Diagnosis for Orthostatic Hypotension

Single Most Likely Diagnosis

• Dehydration: This is often the most common and straightforward cause of orthostatic hypotension, especially if the patient has been experiencing vomiting, diarrhea, or not drinking enough fluids. The body's blood volume is decreased, leading to a drop in blood pressure when standing.

Other Likely Diagnoses

• Autonomic dysfunction: Conditions such as diabetes, amyloidosis, or autoimmune disorders can damage the autonomic nervous system, leading to orthostatic hypotension.
• Anemia: A decrease in red blood cells or hemoglobin can reduce the body's ability to transport oxygen, leading to symptoms of orthostatic hypotension.
• Adrenal insufficiency: A condition where the adrenal glands do not produce enough cortisol and aldosterone, leading to decreased blood pressure and orthostatic hypotension.

Do Not Miss Diagnoses

• Hemorrhage: Internal bleeding can lead to a significant drop in blood pressure and orthostatic hypotension. This is a life-threatening condition that requires immediate attention.
• Cardiac tamponade: Fluid accumulation in the sac surrounding the heart can compress the heart and lead to a decrease in cardiac output, causing orthostatic hypotension.
• Sepsis: A severe infection can cause a drop in blood pressure due to vasodilation and decreased vascular resistance.

Rare Diagnoses

• Pheochromocytoma: A rare tumor of the adrenal gland that can cause orthostatic hypotension due to intermittent release of catecholamines.
• Multiple system atrophy: A rare neurodegenerative disorder that can cause autonomic dysfunction and orthostatic hypotension.
• Dopamine beta-hydroxylase deficiency: A rare genetic disorder that affects the production of norepinephrine, leading to orthostatic hypotension.