1414 - Extremely Rare Manifestation of Pseudogout Leading to Disastrous Functional Decline: A Case Report

84-year-old patient with progressive functional decline and radicular pain found to be secondary to pseudogout at L4-L5.

Case Description:

An 84-year-old male presented with progressively worsening back pain radiating down the right lower extremity with rapid functional decline. He was independently ambulating in December 2024 but became wheelchair dependent by January 2025. He was hospitalized for presumed osteomyelitis at L4-L5 and ventral phlegmon on MRI then treated with IV antibiotics without improvement in symptoms; he underwent bilateral L4 laminectomies due to failure of medical management alone. Biopsy of the phlegmon revealed calcium pyrophosphate crystals, indicating symptoms were likely caused by pseudogout. Rheumatology initiated five days of an interleukin-1 receptor antagonist (IL-1Ra) with transition to oral colchicine. He gained marked improvements in function and pain control with directed treatment of pseudogout.

 

Discussions:

Calcium pyrophosphate deposition (CPPD) or pseudogout is an accumulation of calcium pyrophosphate crystals in the articular and periarticular tissue. Pseudogout generally develops in large joints including the knees, wrists, shoulders, and hips. The presence of CPPD in the spine is rare with cervical spine involvement being most common. There have been very limited published reports of pseudogout in the lumbar spine, but spine involvement usually mimics symptoms of osteomyelitis or discitis. Our patient presented with lower extremity radicular symptoms with presumed osteomyelitis as the cause. To date, there have been just three case reports of lumbar pseudogout reported. This patient underwent months of antibiotics and surgery without significant improvement in symptoms prior to IL-1Ra and colchicine initiation. Early detection via biopsy could have prevented prolonged symptoms and promoted earlier recovery.

Conclusions:

Radiculopathy is a rare presentation of pseudogout. The disease should be considered when assessing for causes of refractory radicular back pain. CPPD is a treatable disease, and with early detection, patient outcomes can improve significantly.