Spontaneous intrahepatic haemorrhage: two cases of segmental arterial mediolysis

Background Segmental arterial mediolysis (SAM) is an under-recognized degenerative vascular disorder with variable clinical presentations. It affects medium to large calibre arteries, typically those arising from the coeliac axis, and its diagnosis is complicated by overlap with other clinical entities like fibromuscular dysplasia. Diagnosis requires histopathological examination of the affected tissue, although radiographic appearances can be suggestive of SAM. Methods We report on two patients presenting with acute rupture of an intrahepatic artery affected by SAM. Results Both patients ultimately required right hemi-hepatectomy in order to either control ongoing bleeding or for removal of liver rendered ischaemic by intra-arterial embolization. This was achieved safely despite additional SAM lesions present throughout the vasculature. Conclusion In both cases described, presentation followed recent, unrelated abdominal surgery and we propose a link between these two events. Recent research has identified the potential role of noradrenaline in the development of SAM lesions in greyhounds, with levels of endogenous noradrenaline known to rise in the setting of surgery.