Two months after thumb injury with constant pain and redness etc; most likely condition?

• A. Arthrofibrosis
• B. Infection
• C. Complex regional pain syndrome
• D. Osteoarthritis

Answer: (C)

Two months after a thumb injury, persistent pain with redness points to a neuropathic pain condition that involves abnormal autonomic regulation of the affected limb. Complex regional pain syndrome presents exactly like this: pain that is out of proportion to the initial injury, along with color and temperature changes, swelling, and other autonomic signs such as sweating. These features reflect abnormal signaling in the peripheral and central nervous systems after trauma, leading to vasomotor and trophic changes in the affected area.

Infection usually brings fever, warmth, possible drainage, or visible wound problems, and the systemic signs are not required for CRPS. Arthrofibrosis focuses on stiffness and restricted range of motion after immobilization or surgery, with less emphasis on color or temperature changes. Osteoarthritis involves degenerative joint changes with pain and stiffness over time, not the acute autonomic changes seen here.

So the combination of persistent, disproportionate pain after trauma plus redness and other autonomic signs is most consistent with complex regional pain syndrome.