Cavernous sinus gas locules can be seen in several settings.
- iatrogenic pneumocephalus secondary to gas embolism (especially venous gas embolism) from IV access (can be a relatively common finding in the absence of direct trauma and does not require treatment).
- traumatic pneumocephalus: in the context of trauma, sphenoid or skull base fracture needs to be excluded in this context
- very rarely infection from a gas-forming organism
Any intravenous injectate administered into the upper extremity normally travel through the axillary, subclavian, and brachiocephalic veins to empty into the superior vena cava. However under certain clinical circumstances such as stenosis of the brachiocephalic vein/SVC, heart failure, coughing etc. it flows cephalad through the internal and external jugular veins into the cranial venous system.
Additionally air locules are lighter than blood, therefore can rise retrogradely up through the jugular veins especially in patients who are in a reclining position. Air bubbles thus accumulate in the highest areas of the head, especially in the cavernous sinuses, frontal venous system, petrosal sinuses, superficial temporal veins, orbital veins etc.
- 1. Sze Mun Mak, Deepa Gopalan. Pictorial review: non-anatomical cardiovascular gas: causes, appearances and consequences. (2018) The British Journal of Radiology. 92 (1093): 20180121. doi:10.1259/bjr.20180121 - Pubmed
- 2. Tran P, Reed EJ, Hahn F, Lambrecht JE, McClay JC, Omojola MF. Incidence, radiographical features, and proposed mechanism for pneumocephalus from intravenous injection of air. (2010) The western journal of emergency medicine. 11 (2): 180-5. Pubmed
- 3. Aliaksandr Anisau, Filip Vanhoenacker. Intravascular Pneumocephalus: A Mimicker of Skull Base Fractures. (2019) Journal of the Belgian Society of Radiology. 103 (1): 29. doi:10.5334/jbsr.1795 - Pubmed