Clinical Reasoning: An Unusual Etiology of Lumbosacral Plexopathy in a Patient With HIV

We present a compelling case of uncontrolled diabetes, who initially presented as diabetic lumbosacral radiculoplexus neuropathy (DLRPN), with radicular pain in the right lower limb (LL) followed by asymmetric weakness of both LLs (right greater than left) with wasting in the medial compartment of the right thigh and significant sensory loss in the bilateral sural and right saphenous nerve distribution. Electrophysiology was suggestive of right lumbosacral radiculoplexus neuropathy. Incidentally, the patient tested positive for HIV-1 at our tertiary care center. CSF analysis revealed markedly elevated protein levels (>400 mg/dL) with lymphocytosis, a red flag for DLRPN. This observation led to further workup. Nerve biopsy showed large collections of perivascular endoneurial and epineurial lymphoid inflammatory cells, which favored an alternative diagnosis. This case highlights the intricate interplay between HIV infection, diabetes, and neurologic manifestations, challenging the initial clinical suspicion of DLRPN. This study emphasizes the importance of considering atypical presentations of neuropathy, especially in the context of coexisting medical conditions, and emphasizes the significance of comprehensive diagnostic workup, including CSF studies and nerve biopsy, for an accurate diagnosis.