Heart Failure: This condition is characterized by the heart's inability to pump enough blood to meet the body's demands, leading to fluid buildup in the lower extremities (causing swelling) and decreased oxygenation of the blood (resulting in dyspnea on exertion). Joint pain can be associated with heart failure due to decreased perfusion and possible embolic events.

Deep Vein Thrombosis (DVT): DVT can cause lower extremity swelling and pain. If the clot breaks loose, it can lead to a pulmonary embolism, causing dyspnea on exertion. Joint pain might not be a direct symptom but can occur due to the inflammatory response.
Chronic Venous Insufficiency: This condition leads to swelling in the legs due to poor blood circulation back to the heart. It can cause joint pain and, in severe cases, lead to dyspnea on exertion if there's significant fluid buildup affecting overall circulation.
Rheumatoid Arthritis: Although primarily an autoimmune disorder causing joint pain and inflammation, severe cases can lead to systemic symptoms, including dyspnea if there's lung involvement (e.g., interstitial lung disease). Lower extremity swelling can occur due to inflammation and decreased mobility.

Pulmonary Embolism: A life-threatening condition where a blood clot blocks an artery in the lung. It can cause sudden onset of dyspnea on exertion and, if originating from a DVT, lower extremity swelling and pain.
Septic Arthritis: An infection within a joint, which can cause severe joint pain and swelling. If the infection spreads or if the patient has a severe systemic response, it can lead to dyspnea on exertion due to sepsis.
Cardiac Tamponade: Fluid accumulation in the sac around the heart can compress the heart, reducing its ability to pump blood effectively. This can lead to dyspnea on exertion and, potentially, lower extremity swelling due to decreased cardiac output.

Sarcoidosis: A condition where inflammatory cells form lumps known as granulomas in various parts of the body, including the lungs and joints. It can cause dyspnea on exertion if lung function is affected and joint pain due to arthritis.
Lymphoma: Certain types of lymphoma can cause systemic symptoms, including dyspnea on exertion if there's lung or mediastinal involvement, and joint pain due to bone marrow infiltration or paraneoplastic syndromes.
Fabry Disease: A genetic disorder that can lead to the accumulation of a particular type of fat in the body's cells, affecting many parts of the body. It can cause joint pain, lower extremity pain and swelling, and dyspnea on exertion due to cardiac or pulmonary involvement.