Joint Pain Approach and Differential Diagnosis
As an internal medicine resident, approaching joint pain requires a thorough evaluation of the patient's symptoms, medical history, and physical examination findings. The differential diagnosis can be organized into the following categories:
- Single Most Likely Diagnosis
- Osteoarthritis (OA): This is the most common cause of joint pain, especially in older adults. OA is characterized by degenerative changes in the joint cartilage and underlying bone, leading to pain, stiffness, and limited mobility. The diagnosis is often made based on clinical presentation and radiographic findings.
- Other Likely Diagnoses
- Rheumatoid Arthritis (RA): An autoimmune disorder that causes inflammation and pain in multiple joints, often symmetrically. RA can lead to significant disability if left untreated.
- Gout: A form of inflammatory arthritis caused by the deposition of urate crystals in the joints, leading to sudden, severe pain and swelling.
- Lupus: A systemic autoimmune disease that can cause joint pain, inflammation, and damage, often accompanied by other symptoms such as skin rashes and kidney disease.
- Fibromyalgia: A chronic condition characterized by widespread musculoskeletal pain, fatigue, and tender points.
- Do Not Miss Diagnoses
- Septic Arthritis: A medical emergency caused by bacterial infection of the joint, which can lead to rapid joint destruction and systemic complications if not promptly treated.
- Lyme Disease: A tick-borne illness that can cause joint pain, fever, and other systemic symptoms, often with a characteristic rash.
- Gonococcal Arthritis: A sexually transmitted infection that can cause joint pain, swelling, and discharge.
- Osteonecrosis: A condition characterized by the death of bone tissue due to inadequate blood supply, often caused by trauma, steroids, or other factors.
- Rare Diagnoses
- Psoriatic Arthritis: A form of arthritis associated with psoriasis, characterized by joint inflammation, skin lesions, and nail changes.
- Ankylosing Spondylitis: A chronic inflammatory disease that affects the spine and other joints, often causing back pain and stiffness.
- Relapsing Polychondritis: A rare autoimmune disorder that causes inflammation and destruction of cartilage in various parts of the body, including the joints.
- Hemochromatosis: A genetic disorder that leads to iron overload, which can cause joint pain, arthritis, and other systemic complications.
Each of these diagnoses has distinct clinical features, and a thorough evaluation is necessary to determine the underlying cause of joint pain. A careful history, physical examination, laboratory tests, and imaging studies can help guide the diagnosis and treatment plan.