Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 54, Num. 4, 2006, pp. 453-454

Neurology India, Vol. 54, No. 4, October-December, 2006, pp. 453-454

Letter To Editor

Supratentorial to infratentorial and antigravity migration of intracranial bullet

Yadav YR, Pandey S, Tiwari M, Agrawal A, Nelson Adam

Neurosurgery Unit, NSCB Medical College, Jabalpur - 428 003, MP
Correspondence Address:Neurosurgery Unit, NSCB Medical College, Jabalpur - 428 003, MP, yadavyr@yahoo.co.in

Code Number: ni06162

Sir,

Anterior migration (antigravity) of bullet is rare.[1] Migration from supratentorial to infratentorial compartment is extremely rare with only four cases having been reported.[2],[3],[4],[5] We report one such rare case of anterior migration of an intracranial bullet from posterior parietal region to sellar region and also from supratentorial compartment to posterior fossa which has not been reported so far in the available literature.

A 30-year-old male became unconscious after a gunshot injury to the head. Glasgow Coma scale (GCS) on admission was E ₂ M ₅ V ₁ . His left pupil was normal sized and normal in reaction while right pupil was dilated and fixed with right eye badly injured. There was right-sided hemiplegia. Entry wound was from right upper eye lid without any exit wound. Computed tomography (CT) scan showed fracture of right orbital roof and ethmoid bone with blood in right maxillary sinus, ethmoidal sinuses and left sylvian fissure. There was contusion in the left basifrontal region, left internal capsule and left frontoparietal region with pneumocephalus. The bullet was lying in the left parietooccipital region superficially [Figure - 1]. The bullet migrated to the suprasellar region [Figure - 2] and then to the posterior fossa [Figure - 3]. There was contusion of dorsal midbrain which was not present in the first or second CT scan. He was shifted to our hospital on the 12th day of injury with GCS of E ₁ V ₁ M ₃ and respiratory rate of 40/min. Patient was put on prophylactic antibiotics (injection ceftriaxone 1g eight-hourly along with injection amikacin 500 mgm 12-hourly).

Emergency suboccipital craniectomy was done and the bullet was extracted from Cisterna magna and the fourth ventricle with duroplasty. Peroperatively, the final position of the bullet was confirmed by X-ray. Bullet was handed over to the police as desired by them, detailed forensic report of the bullet is not available so far. It weighed about 30 gm and was about 10 mm in diameter and 2.5 cm long. Tracheostomy was performed on the same day and patient was put on ventilator. The patient gradually improved but developed bulging at the operative site on the sixth postoperative day. Yet another CT scan revealed collection at operative site with ventricular dilatation. He also had high-grade fever. Cerebro-spinal fluid examination done by lumbar puncture (LP), showed evidence of pyogenic meningitis and grew staphylococcus aurious [sensitive to cefoperazone and sulbactum]. He was treated by repeated drip dry LP and injection cefoperazone 1 g and sulbactum 1 g intravenous eight-hourly. Fever improved and the swelling subsided. A repeat CT scan showed communicating hydrocephalous. LP did not show evidence of active infection. Lumbar-peritoneal shunt (LP shunt) was performed three weeks after craniectomy. He showed gradual improvement thereafter and became conscious three weeks after the LP shunt with residual right-sided hemiparesis. Patient was discharged three months after the admission.

Antigravity (anterior) migration in this case could be due to irritability as the patient was sitting repeatedly with his head bent forward making the sellar region as a dependent portion. From the sellar region the bullet entered the third ventricle and through the aqueduct of sylvious, went into the fourth ventricle. The evidence of it traveling through the aqueduct comes from the third CT scan showing posterior midbrain contusion which was not there in first or second CT scan. The possible mechanisms of migration from the narrow third ventricle and aqueduct to the fourth ventricle could be due to pressure gradient across the bullet and brain pulsations, with the pointed end of the bullet towards the fourth ventricle.

Angiogram (digital subtraction angiography or CT angiography) should be done in cases when a bullet goes across the midline, skull-base, in multilobed injury, especially when bullet is lying near some vessel at the time of surgery. Angiogram was not done in our case as the patient was referred to us late and bullet was well away from the possible injured vessel.

Surgical treatment of retained bullet is a preferred choice of management in order to avoid migration, infection, toxicity, epilepsy and hydrocephalus. There are also reports of good results with conservative management.

References

Copyright 2006 - Neurology India

The following images related to this document are available:

Photo images