JH is a 67-year-old male who presents to the clinic with complaints of dizziness and lightheadedness upon standing. His blood pressure is 140/80 mmHg while sitting but drops to 115/70 mmHg upon standing His past medical history includes type 2 diabetes, hypertension, myocardial infarction (heart attack) at age 63, arthritis, two falls in the past year, and hyperlipidemia. His current medications include: Lantus 50 units at bedtime, amlodipine 5 mg daily, metoprolol succinate 50 mg daily, atorvastatin 40 mg nightly, and aspirin 81 mg daily. He reports starting vitamin D3 5,000 unit capsules two weeks ago based on his wife's recommendation. His symptoms are consistent with

A. Arthritis pain: Arthritis typically causes joint stiffness, pain, and reduced mobility rather than acute changes in blood pressure with position changes. It does not produce dizziness or lightheadedness specifically associated with standing. These symptoms point toward a cardiovascular or autonomic cause rather than musculoskeletal pain. B. Low vitamin D levels: Vitamin D deficiency is associated with bone pain, muscle weakness, and increased fracture risk. It does not cause acute postural blood pressure drops or positional dizziness. Recent vitamin D supplementation is unlikely to explain the described hemodynamic changes. C. Previous falls in the past year: A history of falls is a risk factor and possible consequence of balance or blood pressure abnormalities, but it is not a diagnosis. Falls do not explain the current positional symptoms or documented drop in blood pressure upon standing. D. Orthostatic hypotension: Orthostatic hypotension is defined by a significant drop in blood pressure when moving from sitting to standing, leading to dizziness or lightheadedness. The client’s blood pressure change meets diagnostic criteria and is likely exacerbated by antihypertensive medications and age-related autonomic dysfunction.