What tests should be ordered for a patient with bilateral avascular necrosis (AVN), sebopsoriasis, and a history of topical fluocinolone acetonide (corticosteroid) treatment, who has undergone bilateral core decompression and bone marrow aspirate injection?

Diagnostic Workup for Bilateral AVN with Sebopsoriasis and Prior Corticosteroid Use

Order a comprehensive metabolic panel, complete blood count, lipid panel, coagulation studies, antiphospholipid antibodies, lupus anticoagulant, anticardiolipin antibodies, anti-β2 glycoprotein I antibodies, thyroid function tests, hemoglobin A1c, and consider HIV testing to identify underlying thrombophilic, autoimmune, metabolic, or endocrine conditions that may have contributed to AVN development.

Core Laboratory Evaluation

Metabolic and Hematologic Assessment

• Complete blood count (CBC) to assess for underlying hematologic disorders that predispose to AVN, including sickle cell disease, thalassemia, or other hemoglobinopathies 1
• Comprehensive metabolic panel including liver function tests, as hepatic dysfunction can contribute to AVN risk and corticosteroid metabolism 1
• Serum uric acid levels should be measured, as hyperuricemia has been associated with AVN in psoriatic patients 1
• Hemoglobin A1c to screen for diabetes mellitus, which is a recognized risk factor for AVN development 2

Thrombophilic and Autoimmune Workup

• Antiphospholipid antibody panel including lupus anticoagulant, anticardiolipin antibodies (IgG and IgM), and anti-β2 glycoprotein I antibodies, as thrombophilic conditions significantly increase AVN risk 1, 2
• Coagulation studies including PT/INR, aPTT, protein C, protein S, and factor V Leiden mutation testing to identify inherited or acquired hypercoagulable states 1
• Antinuclear antibody (ANA) with reflex panel to screen for systemic lupus erythematosus, which is strongly associated with AVN and may present with cutaneous manifestations that could be confused with sebopsoriasis 2, 3
• Anti-dsDNA antibodies and complement levels (C3, C4) if ANA is positive, as SLE is a major cause of AVN and requires specific monitoring 4

Lipid and Endocrine Assessment

• Fasting lipid panel as hyperlipidemia is associated with increased AVN risk, particularly in corticosteroid-exposed patients 1
• Thyroid function tests (TSH, free T4) to exclude thyroid disorders that may contribute to bone metabolism abnormalities 2

Infectious Disease Screening

• HIV testing should be strongly considered, as HIV infection is an established risk factor for AVN independent of corticosteroid use 2
• Hepatitis B and C serology to identify chronic viral hepatitis, which can be associated with AVN 5

Additional Considerations for Psoriatic Disease

Rheumatologic Evaluation

• Rheumatoid factor and anti-CCP antibodies to differentiate psoriatic arthritis from rheumatoid arthritis, as treatment implications differ 1
• HLA-B27 testing may be considered if there are features suggesting spondyloarthropathy, though this is not routinely required for AVN workup 1

Monitoring for Methotrexate Exposure

• If the patient has received methotrexate for psoriasis treatment (common in severe cases), baseline liver function tests and renal function are essential, as methotrexate has been associated with AVN in psoriatic patients 1

Imaging Surveillance

• Bilateral hip MRI should be obtained if not already done, as it is the gold standard for detecting early AVN and assessing disease stage 2, 6
• Consider MRI of other weight-bearing joints (knees, ankles) given the bilateral nature of the hip involvement and history of systemic corticosteroid exposure, as multifocal AVN is common 2, 3

Common Pitfalls to Avoid

• Do not assume sebopsoriasis alone explains the AVN—psoriasis itself has been associated with AVN independent of corticosteroid use, but underlying systemic conditions (particularly SLE) must be excluded 1
• Do not overlook the cumulative corticosteroid dose—even topical fluocinolone acetonide can contribute systemically if used extensively, though the threshold for AVN is typically >1 gram cumulative prednisone equivalent 1
• Do not delay thrombophilia workup—identifying hypercoagulable states is critical for preventing progression in the contralateral hip or other joints 1, 2