Differential Diagnosis for Tiredness, Joint Pain, and Stiffness

Single Most Likely Diagnosis

• Osteoarthritis (OA): This is the most common type of arthritis, characterized by wear and tear on a joint, leading to pain, stiffness, and limited mobility. The symptoms described, such as pain around joints and stiffness after sitting for long durations, are classic for OA. Tiredness in the evening can also be associated due to discomfort and reduced mobility.

Other Likely Diagnoses

• Rheumatoid Arthritis (RA): An autoimmune disorder that causes inflammation in the joints, leading to pain, stiffness, and swelling. Morning stiffness is more characteristic, but evening tiredness and joint pain can also occur, especially if the disease is not well-managed.
• Fibromyalgia: A condition characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood issues. The pain and stiffness can be exacerbated by inactivity, such as sitting for long periods.
• Lupus: A chronic autoimmune disease that can affect various parts of the body, including the joints, skin, kidneys, brain, and other organs. Joint pain and stiffness, along with fatigue, are common symptoms.

Do Not Miss Diagnoses

• Septic Arthritis: A medical emergency where a joint becomes infected, leading to severe pain, swelling, and stiffness. While less common, it's critical to diagnose promptly to prevent joint destruction.
• Lymphoma or Other Cancers: Certain cancers can cause joint pain and stiffness, along with systemic symptoms like fatigue. Although rare, missing a diagnosis of cancer can have severe consequences.
• Infectious Diseases (e.g., Lyme Disease, Tuberculosis): These can cause joint pain and stiffness, among other symptoms. Early diagnosis is crucial for effective treatment.

Rare Diagnoses

• Relapsing Polychondritis: A rare disease characterized by recurring episodes of cartilage inflammation, which can affect the joints, ears, nose, and other areas.
• Sjögren's Syndrome: An autoimmune disorder that primarily affects the glands that produce tears and saliva but can also cause joint pain and stiffness.
• Mixed Connective Tissue Disease: A rare autoimmune disorder that combines features of lupus, scleroderma, and rheumatoid arthritis, including joint pain and stiffness.

Each of these diagnoses has a different set of implications for treatment and management, highlighting the importance of a thorough diagnostic process to determine the underlying cause of the symptoms.