Induction of HLA-B27-Associated Reactive Arthritis After a Wharton's Jelly "Stem Cell" Injection.

Orthobiologic injections are an emerging treatment option for musculoskeletal conditions. Allogenic gestational tissue-derived products, including umbilical cord-derived Wharton's jelly, are among the available options. These tissues are currently being harvested and sold by companies as an off-the-shelf "stem cell" injection for conditions such as back pain and osteoarthritis. Despite documented infections from similar umbilical cord derivatives, "stem cell clinics" continue to use them. Here, we report the first documented case of HLA-B27-associated reactive arthritis induced by a Wharton's jelly stem cell injection. A 36-yr-old man was injected with Wharton's jelly for low back pain and within 24 hours developed fevers, chills, polyarthritis, and enthesitis. Infectious disease work-up was negative. Inflammatory markers were elevated and his HLA-B27 antigen was positive. Initial treatment included methylprednisolone and sulfasalazine. This case highlights the unknown dangers of these allogenic injections and physicians should remain cautious about their use until further study and regulation can ensure patient safety.

Free phenytoin toxicity.

Phenytoin has a narrow therapeutic window, and when managing cases of toxicity, clinicians are very wary of this fact. Typically, if patient presents with symptoms suggestive of phenytoin toxicity, total serum phenytoin is promptly ordered. That could be falsely low especially in elderly or critically ill patients, which may lead to a low albumin level resulting in this discrepancy. The free phenytoin can be best estimated using the Sheiner-Tozer equation. Herein, we describe a case of an elderly male patient who presented with drowsiness, gait changes, and elevated liver enzymes and a normal total serum phenytoin level of 18 ng/dL (normal, 10-20 ng/dL).After taking his albumin level into account, his free phenytoin level was calculated to be 27 ng/dL, and the phenytoin was discontinued leading to resolution of his symptoms as well as a return of his liver function panel values to baseline.