Usefulness of Positron Emission Tomography in Patients with Syphilis

Abstract

Background:Diagnosis of syphilis is difficult. Follow-up and therapy evaluation of syphilitic patients are poor. Little is known about positron emission tomography (PET) in syphilis. This review was to systematically review usefulness of PET for diagnosis, disease extent evaluation, follow-up, and treatment response assessment in patients with syphilis.Methods:We searched PubMed, EMBASE, SCOPUS, Cochrane Library, Web of Science, ClinicalTrials.gov, and three Chinese databases (SinoMed, Wanfang, and CNKI) for English and Chinese language articles from inception to September 2016. We also collected potentially relevant studies and reviews using a manual search. The search keywords included the combined text and MeSH terms “syphilis” and “positron emission tomography”. We included studies that reporting syphilis with a PET scan before and/or after antibiotic treatment. The diagnosis of syphilis was based on serological criteria or dark field microscopy. Outcomes include pre- and post-treatment PET scan, pre- and post-treatment computed tomography, and pre- and post-treatment magnetic resonance imaging. We excluded the articles not published in English or Chinese or not involving humans.Results:Of 258 identified articles, 34 observational studies were included. Thirty-three studies were single-patient case reports and one study was a small case series. All patients were adults. The mean age of patients was 48.3 ± 12.1 years. In primary syphilis, increased fluorodeoxyglucose (FDG) accumulation could be seen at the site of inoculation or in the regional lymph nodes. In secondary syphilis with lung, bone, gastrointestinal involvement, or generalized lymphadenopathy, increased FDG uptake was the most commonly detected changes. In tertiary syphilis, increased glucose metabolic activity, hypometabolic lesions, or normal glucose uptake might be seen on PET. There were five types of PET scans in neurosyphilis. A repeated PET scan after treatment revealed apparent or complete resolution of the asymmetry of radiotracer uptake.Conclusion:PET is helpful in targeting diagnostic interventions, characterizing disease extent, assessing nodal involvement, and treatment efficacy for syphilis.

Calvarial lytic lesions in neurosyphilis with ocular involvement

“…Additionally there is conflicting evidence regarding the utility of post-treatment imaging in determining therapeutic impact as certain studies have demonstrated improvement of bone lesions after antibiotic therapy [4] , [5] , [7] , [8] , while others witnessed delayed to no significant changes in lesions [3] , [9] , [14] . Determination of the most efficacious imaging modality for evaluating syphilitic lesions post-treatment requires further investigation, as CT and PET imaging both appear to be reasonable choices for evaluating therapeutic impact [15] . Lastly, surgical management of syphilitic bony lesions remains an option [11] , however there is limited literature available to identify the threshold for intervention.…”

Syphilis Mimicking Malignant Pulmonary Tumor With Nodal and Bone Metastasis on 18F-FDG PET/CT

“…[3][4][5] Gummatous disease in the lungs is uncommon (1%-15%), but it has been reported as avid FDG pulmonary nodules (solitary or multiples) or infiltrates. [5][6][7] On the other hand, generalized lymph nodes with FDG uptake are already well known in many syphilis stages. [5][6][7][8] Syphilis has been known as the "great imitator," and it is still a diagnostic challenge to nuclear medicine physicians due to the syphilitic-related lesions with a high FDG uptake mimicking malignancy.…”

“…A gumma is a hypertrophic mass that may undergo central necrosis and breakthrough of the wall, draining outward. Bone structures are one of the tissues that are more frequently affected by gumma, 2 which leads to bone destruction with increased FDG activity 3–5 . Gummatous disease in the lungs is uncommon (1%–15%), but it has been reported as avid FDG pulmonary nodules (solitary or multiples) or infiltrates 5–7 .…”

“…Bone structures are one of the tissues that are more frequently affected by gumma, 2 which leads to bone destruction with increased FDG activity 3–5 . Gummatous disease in the lungs is uncommon (1%–15%), but it has been reported as avid FDG pulmonary nodules (solitary or multiples) or infiltrates 5–7 . On the other hand, generalized lymph nodes with FDG uptake are already well known in many syphilis stages 5–8 .…”

Aproximación diagnóstica de la neurosífilis

“…Por otra parte, se han adelantado estudios con el uso del 18 flurodeoxiglucosa positron emission tomography (18-FDG-PET) el cual ha permitido identificar 5 diferentes patrones de metabolismo según el estadio de la enfermedad, siendo hipermetabólico en la sífilis primaria en el sitio de inoculación o en los nódulos linfáticos, en la sífilis secundaria con incremento del metabolismo cuando existe compromiso de pulmón, intestino, hueso y linfadenopatias generalizadas y por último en sífilis terciaria se evidencian tanto hipermetabolismo como hipometabolismo y algunas lesiones sin cambios, lo cierto es que después del tratamiento el PET no evidencia alteraciones en quienes presentaron resolución clínica, lo cual debe ser reproducible en otros contextos donde también se evalué la costoefectividad en los países en vía de desarrollo. 23 de Medicina y Cirugía…”