The value of ultrasound and aspiration in differentiating vaso-occlusive crisis and osteomyelitis in sickle cell disease patients

We have studied 50 patients with sickle cell disease who presented with musculoskeletal pain over a 2-year period to assess the use of ultrasound in differentiating infection from infarction, All the patients were evaluated by ultrasound. Five had soft tissue oedema and no fluid collection adjacent to the bone. Forty-five had a subperiosteal fluid collection. Twelve patients whose collections were not aspirated were diagnosed according to clinical evaluation. The remaining 33 patients underwent aspiration under ultrasound guidance to distinguish between an infection and infarction, Twenty-three of these were diagnosed as osteomyelitis and 10 as vaso-occlusive crises. In 21 out of the 23 infected cases, the fluid collection was greater than 10 mm at its thickest point perpendicular to the bone surface and all those with infarction had fluid less than 10 mm thickness. Aspiration under ultrasound guidance is a useful method to differentiate the two clinical entities, In patients suffering from osteomyelitis, identification of the organisms guides antibiotic administration. Needle decompression can help to relieve pain in osteomyelitis and vaso-occlusive crisis. (C) 1999 The Royal College of Radiologists.