Pseudoseptic arthritis: an unusual presentation of neuropathic arthropathy

Septic arthritis is an arthritic condition that arises from infection of synovial (joint) tissues by bacteria or other agents. A case is described of a 49-year-old man who had a condition that mimicked septic arthritis, but was caused by neuropathic arthropathy, a joint disorder in which nerve damage and loss of sensation lead to overuse and repetitive joint injury. The patient had syringomyelia, a fluid-filled cavity within the spinal cord, which contributed to tingling and numbness in the hand, numbness and weakness in the arm, and muscle atrophy. Neuropathic arthropathy occurs in up to 30 percent of patients with syringomyelia, most often involving the shoulder. Diagnosis of the joint problem was delayed by seven months, as the shoulder swelling, although massive, was painless. Many details of this patient's case are typical. Severe destruction of the shoulder developed rapidly, within one month. Neuropathic arthropathy involving the shoulder is thought to involve nerve loss, which then leads to decreased blood flow to bone, and bone resorption (loss of calcium and bone structure). The case is unusual, however, regarding the high level of inflammation and high numbers of white blood cells that were present in the synovial fluid. Bacterial infections were ruled out. This type of inflammatory phase may be a more common feature of early neuropathic arthropathy than realized. Alternatively, it might have been provoked by high synovial fluid levels of fat particles, possibly generated from red blood cells or the breakdown of bone marrow. (Consumer Summary produced by Reliance Medical Information, Inc.)