645 ABSTRACT Achenbach’s Syndrome (AS) is a pathology with low incidence and its etiology is unknown. It is characterized by the acute appea- rance of blue coloration in the finger without a triggering event and might be confused with an ischemic event. However, AS is a self-limited disease without sequelae. This case report is about a 75-year-old woman who presented sudden onset pain and purple coloration in the index finger of her right hand. Diagnostic tests were unhelpful and did not provide relevant information. She received symptomatic treatment, achieving complete resolution. The anamnesis and an exhaustive physical examination play a primary role in the suspicion; leaving diagnostic tests for the exclusion of other pathologies when they are required. We believe that knowing about this pathology allows a correct approach leading to an appropriate diagnosis. Keywords: Achenbach’s syndrome; digital bruising; blue finger; paroxysmal haemorrhage. Level of Evidence: IV Dedo azul agudo idiopático no isquémico: síndrome de Achenbach. Presentación de un caso y revisión bibliográfica RESUMEN El síndrome de Achenbach es un cuadro de baja incidencia y de etiología idiopática. Se caracteriza por la aparición aguda de co- loración azul digital sin un episodio desencadenante, imitando a un cuadro isquémico, pero, al contrario, el síndrome de Achenba- ch se autolimita sin dejar secuelas. Se presenta una mujer de 75 años que consultó en la central de emergencias por dolor y cambio de coloración violácea del dedo índice de su mano derecha, de inicio súbito. Los estudios complementarios no aportaron información relevante. Se administró un tratamiento sintomático y se logró la resolución completa del cuadro. La anamnesis y el examen físico exhaustivo tienen un rol fundamental para sospechar este cuadro y los estudios complementarios se reservan para descartar otras enfermedades, si es necesario. Consideramos que conocer esta enfermedad y un abordaje correcto conducen a un diagnóstico apropiado. Palabras clave: Síndrome de Achenbach; hematoma digital; dedo azul; hemorragia paroxística. Nivel de Evidencia: IV INTRODUCTION Achenbach’s syndrome, also called blue fnger syndrome, paroxysmal fnger hematoma, or acute idiopathic blue fnger, is scarcely described in the literature. 1-6 Although a low incidence is reported—up to fve cases per million inhabitants—its diagnosis could be underestimated. 4,7-9 It has a higher prevalence in the female population between 40 and 60 years of age. 2,7,10,11 Although its etiology is unknown, it has been linked to spontaneous subcutaneous hemorrhage and various hypotheses on the alteration of vascular fow and capillary fragility have been postu- lated to explain this phenomenon. 2,4,5,7,9,12-20 As its presenting clinical characteristics suggest an ischemic episode, Acute Non-Ischemic Idiopathic Blue Finger: Achenbach’s Syndrome. Case Report and Literature Review Juan Ignacio Pérez Abdala, Javier Sánchez Saba, Ezequiel E. Zaidenberg, Gerardo Gallucci, Jorge G. Boretto, Pablo De Carli, Franco L. De Cicco Hand and Upper Limb Surgery Sector, Instituto de Ortopedia y Traumatología “Prof. Dr. Carlos E. Ottolenghi”, Hospital Italiano de Buenos Aires, Autonomous City of Buenos Aires, Argentina CASE PRESENTATION This Journal is licensed under Attribution-NonCommercial-ShareAlike 4.0 International Creative Commons (CC-BY-NC-SA 4.0). Rev Asoc Argent Ortop Traumatol 2021; 86 (5): 645-650 • ISSN 1852-7434 (online) Received on August 9 th , 2020. Accepted after evaluation on December 28 th , 2020 • Dr. JUAN IGNACIO PÉREZ ABDALA • ignacio.perez@hospitalitaliano.org.ar https://orcid.org/0000-0002-5398-6876 How to cite this article: Pérez Abdala JI, Sánchez Saba J, Zaidenberg EE, Gallucci G, Boretto JG, De Carli P, De Cicco FL. Acute Non-Ischemic Idiopathic Blue Finger: Achenbach’s Syndrome. Case Report and Literature Review. Rev Asoc Argent Ortop Traumatol 2021;86(5):645-650. https://doi.org/10.15417/issn.1852-7434.2021.86.5.1182 ID