Differential Diagnosis for SCD Patient with Lower Limb Localized Swelling and High Inflammatory Markers

Single Most Likely Diagnosis

• Acute Bone Infarction: Given the MRI findings suggestive of acute bone infarction in a patient with Sickle Cell Disease (SCD), this is the most likely diagnosis. SCD patients are prone to vaso-occlusive crises, which can lead to bone infarcts due to the sickling of red blood cells causing vascular occlusion.

Other Likely Diagnoses

• Osteomyelitis: Infection of the bone is a possible diagnosis, especially in the context of high inflammatory markers. SCD patients are at increased risk of infections, including osteomyelitis, due to their compromised immune status and potential for skin ulcers.
• Cellulitis or Soft Tissue Infection: The presence of localized swelling and high inflammatory markers could also suggest a soft tissue infection. SCD patients are at risk for these infections, which can sometimes be difficult to distinguish from bone infarcts without imaging.
• Vaso-occlusive Crisis: While not exclusively a diagnosis for the localized swelling, a vaso-occlusive crisis could be the underlying cause of the bone infarction and should be considered in the management of the patient.

Do Not Miss Diagnoses

• Septic Arthritis: Although less common, septic arthritis is a serious condition that requires prompt diagnosis and treatment. The presence of high inflammatory markers and localized swelling could potentially indicate septic arthritis, especially if the patient has a fever or other systemic signs of infection.
• Deep Vein Thrombosis (DVT): SCD patients are at increased risk of thrombotic events, including DVT. While DVT might not directly cause the bone infarction, it's a critical diagnosis to consider due to its potential for severe complications like pulmonary embolism.

Rare Diagnoses

• Bone Tumor: Although rare, a bone tumor could potentially cause localized swelling and elevated inflammatory markers. However, this would be less likely in the context of SCD and the specific MRI findings suggestive of acute bone infarction.
• Eosinophilic Granuloma or Other Rare Bone Conditions: These conditions are rare and might present with localized bone lesions and inflammatory markers. They are less likely in this context but could be considered if other diagnoses are ruled out.