Differential Diagnosis for Severe Joint Pain in All Joints

Single Most Likely Diagnosis

• Rheumatoid Arthritis (RA): This is a common autoimmune disorder that causes inflammation and pain in multiple joints. The symmetric nature of the joint involvement and the presence of morning stiffness are characteristic features that make RA a leading consideration for severe joint pain in all joints.

Other Likely Diagnoses

• Osteoarthritis (OA): Although OA typically affects weight-bearing joints and joints of the hands, in severe cases, it can involve multiple joints, leading to widespread pain. The absence of systemic symptoms and a more gradual onset might distinguish OA from RA.
• Fibromyalgia: Characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood issues. Fibromyalgia is a common cause of diffuse pain and could be considered in the differential for severe joint pain, especially if there's a significant component of muscle pain.
• Systemic Lupus Erythematosus (SLE): An autoimmune disease that can affect various parts of the body, including the joints. SLE can cause severe joint pain and is often accompanied by other systemic symptoms such as skin rashes, kidney problems, and neurological issues.

Do Not Miss Diagnoses

• Septic Arthritis: Although less common, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. It involves a bacterial or fungal infection within a joint and can cause severe pain, swelling, and systemic symptoms like fever.
• Cancer (e.g., Multiple Myeloma, Metastatic Bone Disease): Certain types of cancer can cause widespread joint or bone pain. Early detection is crucial for effective management, making these conditions "do not miss" diagnoses.
• Acute Rheumatic Fever: A complication of untreated streptococcal infection, characterized by migratory polyarthritis among other symptoms. It's essential to diagnose and treat to prevent long-term cardiac complications.

Rare Diagnoses

• Relapsing Polychondritis: A rare autoimmune disorder that affects cartilage and can cause joint pain, among other symptoms like ear and nose cartilage inflammation.
• Sarcoidosis: An inflammatory disease that can affect multiple parts of the body, including the joints, lungs, and eyes. Joint pain in sarcoidosis can be part of a larger constellation of symptoms.
• Hemochromatosis: A genetic disorder leading to iron overload, which can cause joint pain due to iron deposition in the joints, among other systemic effects like liver disease and skin pigmentation.

Each of these diagnoses has distinct features that can help guide the diagnostic process. A thorough history, physical examination, and appropriate laboratory tests are essential for narrowing down the differential diagnosis and reaching a definitive diagnosis.