Differential Diagnosis for Blood Pressure Difference in Right and Left Arm

Single Most Likely Diagnosis

• Atherosclerotic Subclavian Artery Stenosis: This condition is the most common cause of a significant difference in blood pressure between the two arms. It occurs when the subclavian artery, which supplies blood to the arms, becomes narrowed due to atherosclerosis, leading to reduced blood flow and lower blood pressure in the affected arm.

Other Likely Diagnoses

• Subclavian Artery Thrombosis: A blood clot in the subclavian artery can also cause a difference in blood pressure between the arms by obstructing blood flow.
• Thoracic Outlet Syndrome: This condition involves compression of the subclavian artery or vein and can lead to decreased blood pressure in the affected arm.
• Arterial Stenosis or Occlusion: Stenosis or occlusion of other arteries, such as the axillary or brachial arteries, can also cause a difference in blood pressure between the arms.

Do Not Miss Diagnoses

• Aortic Dissection: Although less common, aortic dissection is a life-threatening condition that can cause a difference in blood pressure between the arms due to the disruption of blood flow. It is crucial to consider this diagnosis to avoid missing a potentially fatal condition.
• Takayasu Arteritis: This is a form of large vessel vasculitis that can cause stenosis or occlusion of the subclavian arteries, leading to a difference in blood pressure between the arms. It is essential to recognize this condition due to its potential for serious complications.

Rare Diagnoses

• Coarctation of the Aorta: A congenital condition characterized by the narrowing of the aortic isthmus, which can lead to a difference in blood pressure between the arms, although it typically presents with other symptoms such as hypertension in the arms and decreased or delayed pulses in the lower extremities.
• Pseudocoarctation of the Aorta: A rare condition where the aorta is kinked or bent, potentially causing a difference in blood pressure between the arms.
• Subclavian Steal Syndrome: A condition where there is reversal of blood flow in the vertebral artery due to significant stenosis or occlusion of the subclavian artery, which can lead to symptoms including a difference in blood pressure between the arms.