Sickle cell anemia
Sickle cell disease is the name for a group of inherited conditions that affect the red blood cells. The most serious type is called sickle cell anaemia. Sickle cell disease mainly affects people of African, Caribbean, Middle Eastern, Eastern Mediterranean and Asian origin.
Patients with sickle cell disease or the heterozygous state (sickle-β thalassemia, S-C, S-D disease) frequently experience polyarthralgias. Local sickling of cells leads to obstruction of the microcirculation and to bone infarctions.
Treatment of painful crises includes hydration, oxygen, and analgesics. Other musculoskeletal manifestations including painful large joint arthritis (usually the knees) often with noninflammatory synovial effusions lasting a few days to 3 weeks can also occur.
These effusions are attributable to bone infarctions causing a “sympathetic” transudative effusion, which is unresponsive to intraarticular corticosteroids. Alternatively, some patients during an acute painful crisis will develop a monoarticular or oligoarticular inflammatory arthritis that resolves within a week. Cultures and crystal examinations are negative. Finally, osteonecrosis of larger bones such as the femoral or humeral head is seen in up to 40% of patients with sickle cell disease. Initially, radiographs may be normal. MRI is the most sensitive method to detect early osteonecrosis of the bone.
Osteomyelitis is seen more than 100 times more frequently in sickle cell disease than in normal individuals. It is frequently multifocal. Because of functional asplenia, Salmonella infections account for 50% of osteomyelitis especially in children with sickle cell disease. Septic arthritis is infrequent but is usually caused by Staphylococcus aureus or a gram-negative organism other than Salmonella when it occurs. The large proportion of gram-negative infections may be as a result of bacterial translocation across bowel mucosa that has been compromised by microinfarcts from sickling cells.