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ovale or pulmonary arteriovenous fistula. But small bubbles might pass through the pulmonary filtration system even without a detectable shunt. [3] Carotid arterial distribution strokes are more common due to more distant vertebral artery branching compared to a proximal common carotid artery origin from the aortic arch. However, site of lodgement of air emboli depends on the patient position at the time of event. Prone positioning during PCNL provides a gravitational gradient between the posterior vertebrobasilar circulation and the left heart facilitating entry of air emboli into the posterior vertebrobasilar circulation and the spinal artery. Cerebral arterial air embolism typically involves small arteries and induces pathologic changes by reduction in perfusion distal to the obstruction and an inflammatory response to the air bubble. Temporal association of onset of symptoms with PCNL suggests that the air emboli may have directly entered the pulmonary venous system due to the supracostal approach. There was no identifiable risk factor for cerebrovascular accident in the patient. There was no evidence of intra-cardiac or pre-pulmonary shunt. Prone positioning during the procedure may have facilitated the lodgement of air emboli into the vertebrobasilar system including the spinal artery. A similar case of cerebral and spinal air embolism has been reported by Kachalia AG et al. from our country in 2011.[4] Computed tomography is diagnostic only if obtained immediately because of rapid resorption of air from arterioles. Recent reports investigating the characteristics of CAE, as detected by MRI and DWI, have described scattered cortical gyriform high signal intensities.[5] Therapeutic options for cerebrospinal air emboli include hyperbaric oxygen and heparin. Hyperbaric oxygen presumably induces mechanical compression of air bubbles to a much smaller size and also results in delivery of high doses of oxygen to ischemic brain tissue.[6] Heparin may be useful because the surfaces of air bubbles are covered by a network of fibrin, platelets and fat globules, which induce neutrophil-mediated microvascular damage and activate the intrinsic coagulation cascade.[7]
Suvorit Bhowmick, Kaushik Sarma1, Ashok K. Kayal, Lakshya J. Basumatary Department of Neurology, Gauhati Medical College and Hospital, Guwahati, 1Department of Radiology, Downtown Hospital, Guwahati, Assam, India E-mail: [email protected]
References 1.
222
Song SH, Hong B, Park HK, Park T. Paradoxical air embolism during
2. 3. 4. 5. 6. 7.
percutaneous nephrolithotomy: A case report. J Korean Med Sci 2007;22:1071-3. Tommasino C, Rizzardi R, Bretta L, Venturino M, Piccoli S. Cerebral ischemia after venous air embolism in the absence of intracardiac defect. J Neurosurg Anesthesiol 1996;8:30-4. Thackray NM, Murphy PM, McLean RF, deLacy JL. Venous air embolism accompanied by echocardiographic evidence of transpulmonary air passage. Crit Care Med 1996;24:359-61. Kachalia AG, Savant CS, Patil S, Gupta S, Kapadia FN. Cerebral and spinal air embolism following percutaneous nephrolithotomy. J Assoc Physicians India 2011;59:254-6. Jeon SB, Kim JS, Lee DK, Kang DW, Kwon SU. Clinicoradiological characteristics of cerebral air embolism. Cerebrovasc Dis 2007;23:459-62. Dexter F, Hindman BJ. Recommendations for hyperbaric oxygen therapy of cerebral air embolism based on a mathematical model of bubble absorption. Anesth Analg 1997;84:1203-7. Ryu KH, Hindman BJ, Reasoner DK, Dexter F. Heparin reduces neurological impairment after cerebral arterial air embolism in the rabbit. Stroke 1996;27:303-9. Access this article online Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.132444
Received: 07-02-2014 Review completed: 08-02-2014 Accepted: 06-04-2014
Intracalvarial schwannoma: A case report with review of literature Sir, Intraosseous schwannomas are rare accounting for less than 1% of primary bone tumors. Its occurrence within the skull bone is uncommon. Only seven cases of intracalvarial schwannoma have been reported in the literature,[1] this is probably the eight case. A 41-year-old female presented with insidious onset intermittent parasthesia in right upper and lower limbs and left hemicranial headache of four years duration. She had two episodes of generalized tonic-clonic seizures during this period and was on anti-epileptic drugs. On examination, there were no neurological deficits. The X-ray skull showed an expansile lytic lesion in the left frontal region [Figure 1a]. On magnetic resonance imaging (MRI), it was seen as intradiploic-enhancing lesion, hypointense on T1 and hyperintense on T2 with evidence of calcification within. The inner and outer table around the lesion were sclerotic [Figure 1b]. Radiological diagnosis was hemangioma. The possibility of an intraosseous Neurology India | Mar-Apr 2014 | Vol 62 | Issue 2
[Downloaded free from http://www.neurologyindia.com on Thursday, May 15, 2014, IP: 202.177.173.189] || Click here to download free Android application for this journal Letters to Editor
Table 1: Reported cases of Intraosseous schwannoma involving the skull vault
Authors Celli P et al.[3] Goyal R et al.[1] Erashin Y et al.[2] Schiffer J et al.[2] Unni KK Present case
Age
Sex
Site
Treatment
3 14 11 4 3 Reported two cases; details not available 41
Male Male Male Male Male
Occipital bone Frontal bone Frontal bone Occipital bone Fronto-orbital
Complete excision Complete excision Excision Complete excision Complete excision
14 years 2 years 6 months 1 year
No No No No No
Female
Frontal
Complete excision
3 months
No
schwannoma was not considered at first because of the extreme rarity of this location. Intraoperatively, the tumor was soft, yellowish and seen arising from the diploic space, extending out of inner table on to the dura, but not infiltrating dura. Tumor was excised and acrylic cranioplasty was done. The postoperative period was uneventful. The lesion was nodular mass measuring 4.5 × 3.5 × 2 cm. Cut section was firm, gray-white glistening with areas of hemorrhage [Figure 2a]. Microscopy showed a neoplasm composed of spindle cells with wavy nuclei arranged in short fascicles [Figure 2b] with attempted verocay body formation. Areas of hyalinization, myxoid degeneration, thick-walled congested and thrombosed vessels and areas of hemorrhage were noted within the neoplasm. Cells were strongly and diffusely positive for vimentin and S100 [Figure 3], while negative for smooth muscle antigen (SMA) and epithelial membrane antigen (EMA). A diagnosis of Intraosseous schwannoma of the frontal bone was made after ruling out a smooth muscle and meningothelial neoplasm. Patient is doing well at 3-months follow-up. Schwannoma was first described by Verocay who called it “neurinoma”.[2] Mandible is the most common site of intraosseous schwannoma, followed by vertebrae and long bones.[2] Although, the head and neck region is one of the most common sites for schwannomas, intraosseous skull vault schwannomas are extremly rare.[1] Table 1 summarises the reported seven cases of intraosseous schwannoma of skull vault along with the present case.[1-3] Schwannomas arise almost exclusively from sensory nerves, which may be the reason for rarity of intraosseous schwannomas; the density of sensory nerves within bone being very low. Another postulated origin is from schwann cells of the paravasal nerves, which travel with the nutrient arteries of bone.[1] A microsurgical intracapsular enucleation is the treatment of choice and a complete excision has a good prognosis due to the low recurrence rate and the rarity of malignant transformation.[4] Undetected microscopic deposits can result in recurrence. Radio surgery should be reserved for treatment of unresectable or residual tumors.[5]
Follow-up
a
Recurrence
b Figure 1: (a) Skull radiograph shows an expansile lytic left frontal calvarial lesion. (b) MRI of brain shows left calvarial intradiploic enhancing lesion in the frontal bone
a
b
Figure 2: (a) Cut-section of nodular mass gray-white glistening with areas of hemorrhage (b) Microscopy of Schwannoma; (H and E, ×100)
a
b Figure 3: (a) Diffuse positivity for S100 and (b) Diffuse positivity for vimentin (a and b, ×100)
Departments of Pathology, 1Neurosurgery, 2Imaging Sciences and Interventional Radiolog, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India E-mail: [email protected]
References R. Amita, S. Sandhyamani, Mathew Abraham1, Suresh Nair1, A. Praveen2, T. R. Kapilamoorthy2 Neurology India | Mar-Apr 2014 | Vol 62 | Issue 2
1.
Goyal R, Saikia UN, Vashishta RK, Gulati G, Sharma RK. Intraosseous schwannoma of the frontal bone. Orthopedics 2008;31:281. 223
[Downloaded free from http://www.neurologyindia.com on Thursday, May 15, 2014, IP: 202.177.173.189] || Click here to download free Android application for this journal Letters to Editor
2. 3. 4. 5.
Ersahin Y, Mutluer S, Damirtas E. Intraosseous neurinoma of the parietal bone. Childs Nerv Syst 2000;16:181-3. Celli P, Cervoni L, Colonnese C. Intraosseous schwannoma of the vault of the skull. Neurosurg Rev 1998;21:158-60. Ito S, Mandai T, Ishida K, Deguchi H, Hata T, Irei I, et al. Intraosseous schwannoma of the mandible: A case report. Kawasaki Med J 2009;35:249-52. Ramina R, Mattei TA, Sória MG, da Silva EB Jr, Leal AG, Neto MC, et al. Surgical management of trigeminal schwannomas. Neurosurg Focus 2008;25:E6. Access this article online Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.132447
Received: 19-02-2014 Review completed: 13-03-2014 Accepted: 06-04-2014
Absence status epilepsy: Report of a rare electro-clinical syndrome Sir, We report a patient with “absence status epilepsy” and discuss the features specific to this syndrome. A 49-year-old presented with an acute confusional state, which lasted for more than 24 hours. There was
no family history of seizures. From the age of 16, he started getting generalized tonic-clonic seizures (GTCS) at yearly intervals for 5 years, which subsequently became very infrequent. He was on 500 mg of sodium valproate. From the age of 20, he used to have episodes of confusion and unresponsiveness lasting for hours precipitated by sleep deprivation and emotional disturbances. He used to recover after a nap. These episodes became more frequent and prolonged, interfering with official work and necessitating multiple hospital admissions. There was no history of myoclonic jerks. At admission, he was confused. An urgent video-electroencephalography (EEG) was performed, which showed continuous runs of generalized spike-wave (SW) discharges at 3 Hz [Figure 1a]. He was partially responsive during these events and the discharges became discontinuous when aroused [Figure 1b]. Intravenous lorazepam 2 mg aborted the absence status [Figure 2a]. Subsequently he had intermittent runs of generalized SW discharges at 3 Hz lasting 10-20 seconds, which tapered-off over the next two hours when he recovered completely clinically and electrically. The inter-ictal record showed frontally dominant and generalized fast SW discharges [Figure 2b] suggestive of idiopathic generalized epilepsies (IGE). Hyperventilation and photic stimulation did not activate the discharges. Magnetic resonance imaging (MRI) of brain was normal and ring chromosome-20 was negative. He was put on 1 gm of sodium valproate and is event-free for the past six months. Absence status epilepticus (AS) is a prolonged and non-convulsive seizure occurring in various circumstances. International League Against Epilepsy
a
b Figure 1: EEG showing continuous runs of 3 Hz spike and wave discharges (a) with periods of discontinuity on asking questions (b)
224
Neurology India | Mar-Apr 2014 | Vol 62 | Issue 2
Copyright of Neurology India is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
ovale or pulmonary arteriovenous fistula. But small bubbles might pass through the pulmonary filtration system even without a detectable shunt. [3] Carotid arterial distribution strokes are more common due to more distant vertebral artery branching compared to a proximal common carotid artery origin from the aortic arch. However, site of lodgement of air emboli depends on the patient position at the time of event. Prone positioning during PCNL provides a gravitational gradient between the posterior vertebrobasilar circulation and the left heart facilitating entry of air emboli into the posterior vertebrobasilar circulation and the spinal artery. Cerebral arterial air embolism typically involves small arteries and induces pathologic changes by reduction in perfusion distal to the obstruction and an inflammatory response to the air bubble. Temporal association of onset of symptoms with PCNL suggests that the air emboli may have directly entered the pulmonary venous system due to the supracostal approach. There was no identifiable risk factor for cerebrovascular accident in the patient. There was no evidence of intra-cardiac or pre-pulmonary shunt. Prone positioning during the procedure may have facilitated the lodgement of air emboli into the vertebrobasilar system including the spinal artery. A similar case of cerebral and spinal air embolism has been reported by Kachalia AG et al. from our country in 2011.[4] Computed tomography is diagnostic only if obtained immediately because of rapid resorption of air from arterioles. Recent reports investigating the characteristics of CAE, as detected by MRI and DWI, have described scattered cortical gyriform high signal intensities.[5] Therapeutic options for cerebrospinal air emboli include hyperbaric oxygen and heparin. Hyperbaric oxygen presumably induces mechanical compression of air bubbles to a much smaller size and also results in delivery of high doses of oxygen to ischemic brain tissue.[6] Heparin may be useful because the surfaces of air bubbles are covered by a network of fibrin, platelets and fat globules, which induce neutrophil-mediated microvascular damage and activate the intrinsic coagulation cascade.[7]
Suvorit Bhowmick, Kaushik Sarma1, Ashok K. Kayal, Lakshya J. Basumatary Department of Neurology, Gauhati Medical College and Hospital, Guwahati, 1Department of Radiology, Downtown Hospital, Guwahati, Assam, India E-mail: [email protected]
References 1.
222
Song SH, Hong B, Park HK, Park T. Paradoxical air embolism during
2. 3. 4. 5. 6. 7.
percutaneous nephrolithotomy: A case report. J Korean Med Sci 2007;22:1071-3. Tommasino C, Rizzardi R, Bretta L, Venturino M, Piccoli S. Cerebral ischemia after venous air embolism in the absence of intracardiac defect. J Neurosurg Anesthesiol 1996;8:30-4. Thackray NM, Murphy PM, McLean RF, deLacy JL. Venous air embolism accompanied by echocardiographic evidence of transpulmonary air passage. Crit Care Med 1996;24:359-61. Kachalia AG, Savant CS, Patil S, Gupta S, Kapadia FN. Cerebral and spinal air embolism following percutaneous nephrolithotomy. J Assoc Physicians India 2011;59:254-6. Jeon SB, Kim JS, Lee DK, Kang DW, Kwon SU. Clinicoradiological characteristics of cerebral air embolism. Cerebrovasc Dis 2007;23:459-62. Dexter F, Hindman BJ. Recommendations for hyperbaric oxygen therapy of cerebral air embolism based on a mathematical model of bubble absorption. Anesth Analg 1997;84:1203-7. Ryu KH, Hindman BJ, Reasoner DK, Dexter F. Heparin reduces neurological impairment after cerebral arterial air embolism in the rabbit. Stroke 1996;27:303-9. Access this article online Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.132444
Received: 07-02-2014 Review completed: 08-02-2014 Accepted: 06-04-2014
Intracalvarial schwannoma: A case report with review of literature Sir, Intraosseous schwannomas are rare accounting for less than 1% of primary bone tumors. Its occurrence within the skull bone is uncommon. Only seven cases of intracalvarial schwannoma have been reported in the literature,[1] this is probably the eight case. A 41-year-old female presented with insidious onset intermittent parasthesia in right upper and lower limbs and left hemicranial headache of four years duration. She had two episodes of generalized tonic-clonic seizures during this period and was on anti-epileptic drugs. On examination, there were no neurological deficits. The X-ray skull showed an expansile lytic lesion in the left frontal region [Figure 1a]. On magnetic resonance imaging (MRI), it was seen as intradiploic-enhancing lesion, hypointense on T1 and hyperintense on T2 with evidence of calcification within. The inner and outer table around the lesion were sclerotic [Figure 1b]. Radiological diagnosis was hemangioma. The possibility of an intraosseous Neurology India | Mar-Apr 2014 | Vol 62 | Issue 2
[Downloaded free from http://www.neurologyindia.com on Thursday, May 15, 2014, IP: 202.177.173.189] || Click here to download free Android application for this journal Letters to Editor
Table 1: Reported cases of Intraosseous schwannoma involving the skull vault
Authors Celli P et al.[3] Goyal R et al.[1] Erashin Y et al.[2] Schiffer J et al.[2] Unni KK Present case
Age
Sex
Site
Treatment
3 14 11 4 3 Reported two cases; details not available 41
Male Male Male Male Male
Occipital bone Frontal bone Frontal bone Occipital bone Fronto-orbital
Complete excision Complete excision Excision Complete excision Complete excision
14 years 2 years 6 months 1 year
No No No No No
Female
Frontal
Complete excision
3 months
No
schwannoma was not considered at first because of the extreme rarity of this location. Intraoperatively, the tumor was soft, yellowish and seen arising from the diploic space, extending out of inner table on to the dura, but not infiltrating dura. Tumor was excised and acrylic cranioplasty was done. The postoperative period was uneventful. The lesion was nodular mass measuring 4.5 × 3.5 × 2 cm. Cut section was firm, gray-white glistening with areas of hemorrhage [Figure 2a]. Microscopy showed a neoplasm composed of spindle cells with wavy nuclei arranged in short fascicles [Figure 2b] with attempted verocay body formation. Areas of hyalinization, myxoid degeneration, thick-walled congested and thrombosed vessels and areas of hemorrhage were noted within the neoplasm. Cells were strongly and diffusely positive for vimentin and S100 [Figure 3], while negative for smooth muscle antigen (SMA) and epithelial membrane antigen (EMA). A diagnosis of Intraosseous schwannoma of the frontal bone was made after ruling out a smooth muscle and meningothelial neoplasm. Patient is doing well at 3-months follow-up. Schwannoma was first described by Verocay who called it “neurinoma”.[2] Mandible is the most common site of intraosseous schwannoma, followed by vertebrae and long bones.[2] Although, the head and neck region is one of the most common sites for schwannomas, intraosseous skull vault schwannomas are extremly rare.[1] Table 1 summarises the reported seven cases of intraosseous schwannoma of skull vault along with the present case.[1-3] Schwannomas arise almost exclusively from sensory nerves, which may be the reason for rarity of intraosseous schwannomas; the density of sensory nerves within bone being very low. Another postulated origin is from schwann cells of the paravasal nerves, which travel with the nutrient arteries of bone.[1] A microsurgical intracapsular enucleation is the treatment of choice and a complete excision has a good prognosis due to the low recurrence rate and the rarity of malignant transformation.[4] Undetected microscopic deposits can result in recurrence. Radio surgery should be reserved for treatment of unresectable or residual tumors.[5]
Follow-up
a
Recurrence
b Figure 1: (a) Skull radiograph shows an expansile lytic left frontal calvarial lesion. (b) MRI of brain shows left calvarial intradiploic enhancing lesion in the frontal bone
a
b
Figure 2: (a) Cut-section of nodular mass gray-white glistening with areas of hemorrhage (b) Microscopy of Schwannoma; (H and E, ×100)
a
b Figure 3: (a) Diffuse positivity for S100 and (b) Diffuse positivity for vimentin (a and b, ×100)
Departments of Pathology, 1Neurosurgery, 2Imaging Sciences and Interventional Radiolog, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India E-mail: [email protected]
References R. Amita, S. Sandhyamani, Mathew Abraham1, Suresh Nair1, A. Praveen2, T. R. Kapilamoorthy2 Neurology India | Mar-Apr 2014 | Vol 62 | Issue 2
1.
Goyal R, Saikia UN, Vashishta RK, Gulati G, Sharma RK. Intraosseous schwannoma of the frontal bone. Orthopedics 2008;31:281. 223
[Downloaded free from http://www.neurologyindia.com on Thursday, May 15, 2014, IP: 202.177.173.189] || Click here to download free Android application for this journal Letters to Editor
2. 3. 4. 5.
Ersahin Y, Mutluer S, Damirtas E. Intraosseous neurinoma of the parietal bone. Childs Nerv Syst 2000;16:181-3. Celli P, Cervoni L, Colonnese C. Intraosseous schwannoma of the vault of the skull. Neurosurg Rev 1998;21:158-60. Ito S, Mandai T, Ishida K, Deguchi H, Hata T, Irei I, et al. Intraosseous schwannoma of the mandible: A case report. Kawasaki Med J 2009;35:249-52. Ramina R, Mattei TA, Sória MG, da Silva EB Jr, Leal AG, Neto MC, et al. Surgical management of trigeminal schwannomas. Neurosurg Focus 2008;25:E6. Access this article online Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.132447
Received: 19-02-2014 Review completed: 13-03-2014 Accepted: 06-04-2014
Absence status epilepsy: Report of a rare electro-clinical syndrome Sir, We report a patient with “absence status epilepsy” and discuss the features specific to this syndrome. A 49-year-old presented with an acute confusional state, which lasted for more than 24 hours. There was
no family history of seizures. From the age of 16, he started getting generalized tonic-clonic seizures (GTCS) at yearly intervals for 5 years, which subsequently became very infrequent. He was on 500 mg of sodium valproate. From the age of 20, he used to have episodes of confusion and unresponsiveness lasting for hours precipitated by sleep deprivation and emotional disturbances. He used to recover after a nap. These episodes became more frequent and prolonged, interfering with official work and necessitating multiple hospital admissions. There was no history of myoclonic jerks. At admission, he was confused. An urgent video-electroencephalography (EEG) was performed, which showed continuous runs of generalized spike-wave (SW) discharges at 3 Hz [Figure 1a]. He was partially responsive during these events and the discharges became discontinuous when aroused [Figure 1b]. Intravenous lorazepam 2 mg aborted the absence status [Figure 2a]. Subsequently he had intermittent runs of generalized SW discharges at 3 Hz lasting 10-20 seconds, which tapered-off over the next two hours when he recovered completely clinically and electrically. The inter-ictal record showed frontally dominant and generalized fast SW discharges [Figure 2b] suggestive of idiopathic generalized epilepsies (IGE). Hyperventilation and photic stimulation did not activate the discharges. Magnetic resonance imaging (MRI) of brain was normal and ring chromosome-20 was negative. He was put on 1 gm of sodium valproate and is event-free for the past six months. Absence status epilepticus (AS) is a prolonged and non-convulsive seizure occurring in various circumstances. International League Against Epilepsy
a
b Figure 1: EEG showing continuous runs of 3 Hz spike and wave discharges (a) with periods of discontinuity on asking questions (b)
224
Neurology India | Mar-Apr 2014 | Vol 62 | Issue 2
Copyright of Neurology India is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
