Study Design and Location

We conducted a retrospective study to evaluate epidemiological, clinical, and radiological characteristics of patients with SNPT and to compare these with patients diagnosed with SPPT. The study location was Hospital de Clínicas de Porto Alegre (HCPA), a general, tertiary care, university-affiliated hospital with 750 beds and approximately 29,000 hospitalizations/year. It is a reference center for HIV in south of Brazil. The ethics committee at Hospital de Clínicas de Porto Alegre has approved access to patient records on January 22^nd, 2013 (number 13–0024). Patient confidentiality has been maintained.