[CanLyme Note: This report relates that their is reason to double check positive CSF PCR tests for Lyme disease. There is a very small risk of false positive results. The bigger risk is false negative results as outlined in this presentation, “PCR testing of CSF is positive in only about one third of US patients with early neuroborreliosis, and it is even less sensitive in patients with late neurologic disease.”]
We report a 63‐year‐old man, who developed bilateral atrophic arm paresis with preserved reflexes. Criteria for probable, laboratory‐supported ALS (El Escorial) were fulfilled. However, cerebrospinal spinal fluid analysis revealed neuroborreliosis. We give a detailed description of our patient’s case and review literature on neuroborreliosis‐associated ALS mimics.