You are examining a female patient who presents with constant burning pain in her right hand, wrist, and distal forearm that has spread proximally over the preceding two weeks to the point where the patient complains of loss of use of her right upper extremity, which at times feels ultimately cold and hot. The patient reports being stung in the left foot by a stingray two months previously and subsequently developed severe cellulitis in that extremity, which required hospitalization. The patient also reports that she has been seeing a psychologist for anxiety for the past two years.

Thus far, radiographic and MRI data for the neck, shoulder, and lungs were negative, but radiographs of the involved hand demonstrated patchy osteopenia. No systemic involvement had been detected.

The physical examination reveals moderate swelling to the right hand and wrist, including slight fusiform swelling to the fingers of the right hand. Light moisture appears to cover the whole right hand as if it were sweating, and when compared to the contralateral hand, the involved hand appears shiny. Even when using a light touch, the patient cringes and pulls away. The right wrist and fingers have mild to moderate stiffness, with the fingers positioned in slight flexion. There is also a flattening of the palmar crease lines over the interphalangeal and metacarpophalangeal joints. Strength testing was deferred secondary to pain and tenderness. Sensory testing reveals paresthesia in a glove and stocking type of distribution over the distal right extremities.

Which of the following is most likely the cause of the signs and symptoms?

1. Complex regional pain syndrome (CRPS)
2. Scleroderma
3. Venous obstruction
4. Rheumatoid arthritis (RA)

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