A middle aged man was referred for reveiw of his "foot cellulitis", not improving despite antibiotics. He had a tender, red swelling over the medial and distal part of his left foot, which was painful.
The first MTP joint is swollen with a distended capsule. There is thickening of the overlying soft tissue. The contralateral (normal) side is shown for comparison.
A diagnosis of gout was suspected (the patient's first episode). This can sometimes be difficult to distinguish from infection (either cellulitis or septic arthritis), particularly if there are systemic symptoms. Ultrasound in this case confirmed the joint involvement, which would not be expected in cellulitis. Given the strong clinical suspicion of gout and low suspicion for septic arthritis, a joint aspirate was not performed, although in cases of doubt it should be.