Bony changes of sickle cell anemia
Sickle cell anemia is secondary to a disorder of “sickling” of red blood cells resulting from abnormal hemoglobin molecules.
Clumped sickled cells form venous (and sometimes arterial) thromboses, affecting multiple organs.
Osseous manifestations include patchy sclerotic changes in bone from infarctions. A more specific sign includes a “Lincoln log” appearance of the vertebral bodies, with square-like depressions seen in the superior and inferior endplates on a lateral spine radiograph.
Avascular necrosis of the femoral or humeral heads may also be seen. Affected patients are prone to osteomyelitis from Staphylococcus aureus and Salmonella . On MRI, it can be difficult to distinguish infarction from osteomyelitis because both may produce signal abnormalities in marrow (high T2-weighted signal intensity) along with adjacent soft tissue changes. Dactylitis is a nonspecific term referring to inflammation of a digit, which may also be seen in sickle cell anemia secondary to infarction or infection. Finally, because of chronic anemia, patients with sickle cell anemia have an increased red-to-yellow marrow ratio, which may be inferred on a lateral skull radiograph by the widening of the diploic space