Kager's fat pad inflammation associated with HIV infection and AIDS: MRI findings

Area of Science:

• Radiology
• Orthopedics
• Infectious Diseases

Background:

• Protease inhibitor (PI) treatment for human immunodeficiency virus (HIV) can lead to lipodystrophy syndrome.
• Lipodystrophy can manifest with various symptoms, including musculoskeletal pain.
• Posterior ankle pain is a common complaint, and its causes in HIV-positive patients require investigation.

Purpose of the Study:

• To describe the magnetic resonance imaging (MRI) features of Kager's fat pad inflammation.
• To investigate the association between Kager's fat pad inflammation and posterior ankle pain in HIV-positive patients with lipodystrophy.
• To differentiate these findings from other patient groups.

Main Methods:

• A case-control, cross-sectional study design was employed.
• Four groups were analyzed: HIV+ patients with PIs, lipodystrophy, and ankle pain; HIV-negative patients with ankle pain; HIV+ patients without PIs or lipodystrophy; and HIV+ patients with PIs and lipodystrophy but no ankle pain.
• Radiologists evaluated MRI scans for Kager's fat pad edema, blinded to clinical data. Statistical analysis included Fisher's exact test and Cohen's kappa for interobserver agreement.

Main Results:

• Edema in Kager's fat pad was significantly associated with symptoms in HIV-positive patients experiencing lipodystrophy (p ≤ 0.0001).
• Interobserver agreement for the MRI findings was excellent (Cohen's kappa > 0.9).
• The study identified a strong correlation between specific MRI findings and clinical presentation.

Conclusions:

• MRI findings of Kager's fat pad inflammation are linked to symptoms in HIV-positive patients.
• Protease inhibitor treatment and associated lipodystrophy syndrome are implicated in Kager's fat pad inflammation causing posterior ankle pain.
• This study highlights a specific imaging finding as a source of pain in a defined HIV-positive patient population.