RESUMO
Acute myelopathy includes a group of diseases with an important associated morbidity, thus early diagnosis and treatment is important. The most frequent etiology is extramedullary compression. Magnetic resonance (MR) is the most suitable procedure in this type of disease since it also offers information on extramedullar lesions and makes it possible to assess spine involvement. We present the case of a 57 year-old man who was admitted because of back pain for several weeks and systemic infection due to S. aureus. Later, he suffered a sudden neurological deficit with spine involvement but without compressive images on the MRI. We discuss the differential diagnosis among intramedullary abscess, epidural abscess, acute transverse myelitis and spondylodiscitis associated to acute myelopathy. We carry out a brief review of the medical literature on diagnosis criteria of those entities.