Hip bone osteonecrosis with intraosseous pneumatosis after abdominal aortic aneurysm repair: a case of emphysematous osteomyelitis

Intraosseous pneumatosis is a rare and often fatal condition characterised by air accumulation in the bone that may be brought about by infection, trauma (surgical or otherwise), degenerative disease or neoplastic processes. Here, we present a case of pelvic emphysematous osteomyelitis following repair of an infected abdominal aortic aneurysm. A 56-year-old Saudi male, known to have diabetes and hypertension, presented to the emergency department complaining of intermittent abdominal pain over the right lower quadrant. The patient was later diagnosed intraoperatively with an infected abdominal aortic aneurysm and treated appropriately. During multiple follow-up imaging studies, the patient was noted to have multiple intra-abdominal fluid collections, as well as intraosseous pneumatosis in the pelvis and right femur. 3 months later, intervention was again required due to patient deterioration and possible aortic graft leakage. Graft abscess was diagnosed and managed. We present a case of an infected abdominal aortic aneurysm that eventually led to emphysematous osteomyelitis of the pelvis. This case report sheds light on intraosseous pneumatosis and emphysematous osteomyelitis, which is characterised by the former, in addition to signs of an underlying infection or abscess formation.