A 26‐year‐old white female with a past medical history of right patellar fracture that was surgically corrected with fixation in 2006 fell on her right knee 1 month prior To presenting to the emergency room with gradually increasing swelling of the right leg. The swelling was insidious in onset, associated with pain that was burning in nature, and aggravated by ambulation. There was no history of travel, insect bite, or deep vein thrombosis. Patient has no known allergies. On physical examination, vital signs were stable. Significant physical findings included right lower limb edema, which was noted to be 3+ nonpitting edema present to the midshin along with erythema and tenderness. There was normal range of motion present. She voiced concern regarding increased sensation to pain and pressure as compared with the left foot. Laboratory findings showed normal WBC count and unremarkable blood chemistry test. A Doppler ultrasound ruled out venous thromboembolism. X‐ray of the right knee and ankle showed prior internal fixation of patellar fracture with no acute abnormality and showed no evidence of acute bony trauma or diffuse soft‐tissue edema, but possible early occult osteomyelitis could not be ruled out, and the radiologist recommended further evaluation via a 3‐phase bone scan or white blood cell study if there was a high suspicion for osteomyelitis. However, she was diagnosed with cellulitis, discharged from the ECC on oral antibiotics with instructions to follow up in the primary care clinic within 1 week. At her follow‐up clinic visit, it was noted that the patient's symptoms had not resolved, and she had also developed antibiotic‐induced nausea and vomiting. She was then admitted to the inpatient medical service for further evaluation. A 3‐phase bone scan was obtained that showed tracer uptake consistent with That of reflex sympaThetic dystrophy. No scintigraphic evidence of osteomyelitis was seen. Antibiotics were slopped, and the patient was started on low‐dose oral steroids, and she responded with decreased pain and swelling of her right lower extremity. She also benefited from physical therapy.
Complex regional pain syndrome, formerly known as reflex sympathetic dystrophy, is an exaggerated sympathetic response to an injured limb.. Usual features are pain (intense or unduly prolonged), vasomotor disturbances, delayed functional recovery, and trophic changes. Mitchell, Morehouse, and Keen (1864) were the first to describe it. This syndrome is a diagnostic challenge, as it is often characterized by extensive changes in skin color and temperature that can be mistaken for cellulitis
This case illustrates the need to include complex regional pain syndrome in the differential diagnoses of pain in an extremity. Early diagnosis is critical to prevent unnecessary and potentially harmful antibiotic prescribing, provide timely symptomatic relief so as to decrease morbidity, and enhance the patient's understanding of the disease.
A. A. Oommen, none; S. L. Garrett, none.