Conclusion: In our patient tension pneumocephalus was complicated by diabetes insipidus and leading to cerebral sinus thrombosis after surgery.

Endovascular embolization of cerebral aneurysm is common in clinical practice. The rare complication of endovascular embolization is coil misplacement. Most of the reported coil misplacements occur due to premature release of a coil into the cerebral circulation. We report a case of a coil lost into the peripheral circulation due to failed detachment from the micro-catheter at the right place.Case: A young lady without medical history, presented at the emergency department with severe headache. Her consciousness level deteriorated, and her GCS dropped to 5, requiring immediate intubation, sedation and ventilation. Computer tomography and angiography showed a giant supraclinoid aneurysm of the left internal carotid artery. She was taken for endovascular coiling under general anesthesia and one coil was successfully inserted in the aneurysm. During the insertion of the second coil, it was not possible to detach the coil from the micro-catheter, the coil got stuck at the level of the carotid bifurcation and after several failed attempts to remove it, the coil was swept away into the general circulation and went undetected on fluoroscopy. Next day extremity X-ray showed the coil in the left popliteal artery. Patient was taken for angiography, the misplaced coil was successfully removed and the aneurysm was completely embolized. Her condition improved with supportive care and by day 14 she was successfully extubated and discharged home after another week. Conclusion:During embolization coil can fail to get detached from the catheter and can go into the peripheral circulation.