- Email: [email protected]
Impaired vision associated with a solitary intracranial plasmacytoma
Case Reports / Journal of Clinical Neuroscience 17 (2010) 1215–1217
4. Conclusion The diagnosis of RCC metastasis within an HAB might be overlooked because they have similar morphological characteristics. Detailed histological analyses and immunohistochemistry should be helpful to determine whether HAB contain metastatic lesions, especially in patients with VHL syndrome.
References 1. Jarrell ST, Vortmeyer AO, Linehan WM, et al. Metastases to hemangioblastomas in von Hippel–Lindau disease. J Neurosurg 2006;105:256–63. 2. Caroli E, Salvati M, Giangaspero F, et al. Intrameningioma metastasis as first clinical manifestation of occult primary breast carcinoma. Neurosurg Rev 2006;29:49–54. 3. Plate KH, Vortmeyer AO, Zagzag D, et al. Von Hippel-Lindau disease and haemangioblastoma. In: Louis DN, Ohgaki H, Wiestler OD, et al., editors. WHO Classification of Tumors of the Central Nervous System. Lyon: IARC; 2007. p. 215–7. 4. Hamazaki S, Nakashima H, Matsumoto K, et al. Metastasis of renal cell carcinoma to central nervous system hemangioblastoma in two patients with von Hippel-Lindau disease. Pathol Int 2001;51:948–53.
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5. Sella A, Ro JY. Renal cell cancer: best recipient of tumor-to-tumor metastasis. Urology 1987;30:35–8. 6. Jamjoom A, Kane N, Nicoll J. Metastasis of a renal carcinoma to a cerebellar haemangioblastoma in a case of von Hippel–Lindau disease. Neurosurg Rev 1992;5:231–4. 7. Bret P, Streichenberger N, Guyotat J. Metastasis of renal carcinoma to a cerebellar hemangioblastoma in a patient with von Hippel Lindau disease: a case report. Br J Neurosurg 1999;13:413–6. 8. Mottolese C, Stan H, Giordano F, et al. Metastasis of clear-cell renal carcinoma to cerebellar hemangioblastoma in von Hippel Lindau disease: rare or not investigated? Acta Neurochir (Wien) 2001;143:1059–63. 9. Abou-Hamden A, Koszyca B, Carney PG, et al. Metastasis of renal cell carcinoma to haemangioblastoma of the spinal cord in von Hippel-Lindau disease: case report and review of the literature. Pathology 2003;35:224–7. 10. Altinoz MA, Santaguida C, Guiot MC, et al. Spinal hemangioblastoma containing metastatic renal cell carcinoma in von Hippel-Lindau disease. Case report and review of the literature. J Neurosurg Spine 2005;3:495–500. 11. Polydorides AD, Rosenblum MK, Edgar MA. Metastatic renal cell carcinoma to hemangioblastoma in von Hippel-Lindau disease. Arch Pathol Lab Med 2007;131:641–5. 12. Clelland CA, Treip CS. Histological differentiation of metastatic renal carcinoma in the cerebellum from cerebellar haemangioblastoma in von Hippel-Lindau’s disease. J Neurol Neurosurg Psychiatry 1989;52:162–6. 13. Roy S, Chu A, Trojanowski JQ, et al. D2–40, a novel monoclonal antibody against the M2A antigen as a marker to distinguish hemangioblastomas from renal cell carcinomas. Acta Neuropathol 2005;109:497–502.
doi:10.1016/j.jocn.2009.12.027
Impaired vision associated with a solitary intracranial plasmacytoma Xiaoyun Cao a, Shihai Luan a, Linlin Sun b, Bojie Yang a, Chao Shen a, Weimin Bao a,* a b
Department of Neurosurgery, Huashan Hospital of Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China Department of Radiology, Huashan Hospital of Fudan University, Shanghai, China
a r t i c l e
i n f o
Article history: Received 23 November 2009 Accepted 29 December 2009
Keywords: Extramedullary plasmacytoma Intracranial plasmacytoma Plasma cell tumor Solitary intracranial plasmacytoma Neurosurgery Radiotherapy
a b s t r a c t Solitary intracranial plasmacytomas (SICPs) are extremely uncommon tumors in the central nervous system, and are often misdiagnosed pre-operatively. We report a patient with SICP, describe the neuroradiological and neurosurgical features and the clinical management of this patient, and review the pertinent literature. Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved.
1. Case report A 59-year-old man with a 2-month history of impaired vision was admitted to hospital; nothing remarkable was found in his past history. A neurological examination revealed temporal hemianopsia in his left eye, while his right eye only possessed light perception; his cranial nerve examination was normal. Routine blood and urine tests, endocrine profile, a skeletal survey and an examination of a bone marrow aspirate were all unremarkable. A CT scan of the head revealed an intrasellar and intrasphenoidal-sinus lesion, which had eroded the anterior clinoid process and clivus bone. The mass had also partially occluded the suprasellar cistern, and compressed the anterior parts of the third ventricle * Corresponding author. Tel.: +86 21 6248 9999; fax: +86 21 5030 1919. E-mail address: [email protected] (W. Bao).
and lateral ventricle. An MRI scan revealed a large mass located in the sellar region and sphenoidal sinus, with a hypointense signal intensity on T1-weighted images and significant enhancement after administration of gadolinium-diethylenetriamine penta-acetic acid (GD-DTPA) (Fig. 1). Furthermore, the intracranial lesion was solitary on a full-body positron emission tomography (PET)/ CT scan. Pre-operatively, the preliminary diagnosis was a chordoma. Using a transsphenoidal approach, the mass was subtotally resected. During the resection, it was observed that the lesion was soft, fleshy and highly vascular, with a poorly defined border, which involved the bone and dura. A hematoxylin and eosin stain of the resected sample demonstrated typical plasma cells. Immunohistochemical stains revealed the cells were kappa positive (+), lambda negative, and CD79a+; the MIB-1 index of the tumor was 20% (Fig. 2).
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Case Reports / Journal of Clinical Neuroscience 17 (2010) 1215–1217
Fig. 1. (a) Coronal head CT scan revealing an intrasellar and intrasphenoidal-sinus lesion, eroding the anterior clinoid processes and clivus. (b) Coronal T1-weighted MRI scan showing a hypointense signal intensity mass. (c) Sagittal T1-weighted contrast enhanced MRI, the lesion is significantly enhanced by gadolinium-diethylenetriamine pentaacetic acid (GD-DTPA).
Fig. 2. Histological examination of the resected tumor sample showing (a) typical plasma cells (hematoxylin and eosin, original magnification 400), (b) immunoglobulin light chains (blue cells), confirming kappa restriction (immunoperoxidase), (c) positive staining for CD79a (immunoperoxidase) and (d) a MIB-1 index of 20% (immunoperoxidase). (This figure is available in colour at www.sciencedirect.com.)
Post-operatively, the patient’s vision was slightly improved. He received 60 Gy of radiotherapy, and it was recommended that follow-up MRI scans should be taken. 2. Discussion Plasma cell tumors, may occur in multiple myeloma (MM), as solitary bone plasmacytomas or as extramedullary plasmacytomas. Extramedullary plasmacytomas, which occur in extraosseous sites, account for 3% of plasma cell neoplasms. Solitary intracranial plasmacytoma (SICP), a rare form of extramedullary plasmacytoma, generally arises from lesions of the dura, leptomeninges or parenchyma, but may involve the cranial vault, skull base, orbits, nasal cavity, paranasal sinuses, meninges and brain. We describe a patient with a SICP and review the related literature. We found 39 cases of SICP reported in the literature.1–3 Most patients were male. This tumor may occur at any age, but is mostly seen in patients in their fifties or sixties. The clinical and neuroradiological findings are generally non-specific, so SICPs are often misdiagnosed pre-operatively. In 1954, Clarke divided cranial myelomas into three clinical groups: (i) group I, which usually involve the skull base but do
not involve the brain parenchyma, and with which cranial nerve palsies are often seen; (ii) group II, which involve the brain parenchyma, with or without origin from the skull; and (iii) group III, which are intra-orbital tumors.4 Our patient had a group I tumor being an intracranial tumor compressing the optical nerve and invading into the skull base, without involvement of the brain parenchyma. The clinical characteristics of SICPs are determined by the location and size of the neoplasm. Raised intracranial pressure, confusion, cranial nerve palsies and seizures are commonly seen in patients whose lesions are located in the cranial vault and the skull base. Involvement of the orbits may result in orbital pain and exophthalmos. Diplopia may result both from the direct effect of an orbital plasmacytoma or from ophthalmoplegia caused by cranial nerve involvement, commonly in the cavernous sinus. Patients with leptomeningeal masses frequently present with paraparesis. On non-enhanced CT scans, the extra-axial SICPs generally appear hyperdense. CT is better than MRI scan in delineating subtle bone erosions. On MRI scan, an intracranial plasmacytoma commonly demonstrates iso- to hypointense signal on T1-weighted images, and an iso- to hyperintense signal on T2-weighted images. On both CT and MRI scans, there may be mild to significant
Case Reports / Journal of Clinical Neuroscience 17 (2010) 1217–1219
enhancement. Restricted diffusion may be seen in diffusionweighted imaging and apparent diffusion coefficient maps. Generally, SICPs may appear similar to meningioma, metastasis, lymphoma, dural sarcoma, plasma cell granuloma, infectious meningitis and leptomeningeal carcinomatosis on imaging, thus they have no specific neuroradiological features. This should be taken into account in the differential diagnosis. The confirmation of a SICP relies on histopathological results and a thorough investigation to exclude the presence of neoplasms elsewhere in the body, including systemic MM. The accepted treatment of SICP is complete or subtotal resection followed by at least 50 Gy radiotherapy.1 Our patient was treated with radiotherapy and will receive follow-up MRI scans. Patients with SICP have more favorable outcomes than those with systemic MM therefore it is prognostically significant to
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determine whether a plasmacytoma is solitary. Subtotal or radical resection combined with radiotherapy may result in a favorable remission. References 1. Vujovic O, Fisher BJ, Munoz DG. Solitary intracranial plasmacytoma: case report and review of management. J Neurooncol 1998;39:47–50. 2. Cakir E, Karaarslan G, Usul H, et al. Solitary plasmacytoma with intracranial intraorbital and, paranasal sinus extension. J Clin Neurosci 2003;10:266–8. 3. Brannan SO, Matthews BN, Savant V, et al. Solitary intracranial extra-osseous plasmacytoma presenting with ophthalmic signs. J Neuroophthalmol 2003;23:268–71. 4. Clarke E. Cranial and intracranial myelomas. Brain 1954;77:61–81.
doi:10.1016/j.jocn.2009.12.023
An electrophysiological study of the intermediate syndrome of organophosphate poisoning Paulo José Lorenzoni, Juliano Gasparetto, Cláudia Suemi Kamoi Kay, Rosana Herminia Scola *, Lineu César Werneck Division of Neurology, Department of Internal Medicine, Hospital de Clínicas da Universidade Federal do Paraná (UFPR), Rua General Carneiro 181, Curitiba PR 80060-900, Brazil
a r t i c l e
i n f o
Article history: Received 11 September 2009 Accepted 22 November 2009
Keywords: Electrophysiological study Intermediate syndrome Organophosphate poisoning Repetitive nerve stimulation
a b s t r a c t Acute organophosphate (OP) poisoning is commonly seen in emergency medicine. Neurologists must be alert to detect neuromuscular transmission failure and other neurological complications that follow OP poisoning. We report a 37-year-old male with acute OP poisoning to emphasize the electrophysiological abnormalities during the intermediate syndrome (IMS). Motor nerve conduction studies revealed that a single nerve stimulation evoked a repetitive compound muscle action potential, whereas repetitive nerve stimulation resulted in a combination of a decrement–increment pattern and a repetitive fade response. Thus, electrophysiological studies can be used to monitor patients with IMS, and these test results correlate well with clinical findings in acute OP poisoning. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction The organophosphates (OP) comprise a large group of compounds that have the potential to irreversibly inhibit cholinesterase, acetylcholinesterase (AChE) and target nerve esterase.1,2 OP poisoning leads to three main clinical syndromes: (i) acute cholinergic syndrome; (ii) intermediate syndrome (IMS); and (iii) peripheral neuropathy.2–4 In 1957, Senanayake and Karalliedde described a syndrome of muscular paralysis that occurred in awake patients 24 hours to 96 hours after a cholinergic syndrome caused by OP ingestion that had been treated with atropine.3,5 This syndrome usually follows acute cholinergic syndrome and precedes a delayed neuropathy; thus, it is referred to as the ‘‘intermediate syndrome”. IMS has been noted late in the course of cholinergic syndrome in several patients, and is marked by weakness and fatigue of skeletal muscles with fasciculation leading to respiratory muscle paralysis.1–6
* Corresponding author. Tel.: +55 41 33601800; fax: +55 41 32430182. E-mail address: [email protected] (R.H. Scola).
A diagnosis of OP poisoning is based on the characteristic clinical features and history of exposure to a known OP compound.1 The concentration of serum OP may be tested in patients suspected of OP exposure; however, serum cholinesterase level and electrophysiological studies are helpful in confirming the diagnosis.1,3 Acute OP poisoning is important in emergency medicine in many underdeveloped countries.1,4 Neurologists working in these countries must be alert to detect neuromuscular transmission failure and other neurologic complications that follow OP poisoning.1,7,8 We report a patient with acute OP poisoning to highlight the electrophysiological abnormalities observed during IMS. 2. Case report A 37-year-old male was referred to our hospital 12 hours after the ingestion of an unknown poison. He presented with swallowing difficulties and increased perspiration and oral and bronchial secretions. Physical examination showed bradycardia, hypotension, conjunctival hyperemia and miosis (pinpoint pupils), and revealed the patient to be in a stupor. The clinical features were thought to be consistent with acute OP poisoning. A reduction of
4. Conclusion The diagnosis of RCC metastasis within an HAB might be overlooked because they have similar morphological characteristics. Detailed histological analyses and immunohistochemistry should be helpful to determine whether HAB contain metastatic lesions, especially in patients with VHL syndrome.
References 1. Jarrell ST, Vortmeyer AO, Linehan WM, et al. Metastases to hemangioblastomas in von Hippel–Lindau disease. J Neurosurg 2006;105:256–63. 2. Caroli E, Salvati M, Giangaspero F, et al. Intrameningioma metastasis as first clinical manifestation of occult primary breast carcinoma. Neurosurg Rev 2006;29:49–54. 3. Plate KH, Vortmeyer AO, Zagzag D, et al. Von Hippel-Lindau disease and haemangioblastoma. In: Louis DN, Ohgaki H, Wiestler OD, et al., editors. WHO Classification of Tumors of the Central Nervous System. Lyon: IARC; 2007. p. 215–7. 4. Hamazaki S, Nakashima H, Matsumoto K, et al. Metastasis of renal cell carcinoma to central nervous system hemangioblastoma in two patients with von Hippel-Lindau disease. Pathol Int 2001;51:948–53.
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5. Sella A, Ro JY. Renal cell cancer: best recipient of tumor-to-tumor metastasis. Urology 1987;30:35–8. 6. Jamjoom A, Kane N, Nicoll J. Metastasis of a renal carcinoma to a cerebellar haemangioblastoma in a case of von Hippel–Lindau disease. Neurosurg Rev 1992;5:231–4. 7. Bret P, Streichenberger N, Guyotat J. Metastasis of renal carcinoma to a cerebellar hemangioblastoma in a patient with von Hippel Lindau disease: a case report. Br J Neurosurg 1999;13:413–6. 8. Mottolese C, Stan H, Giordano F, et al. Metastasis of clear-cell renal carcinoma to cerebellar hemangioblastoma in von Hippel Lindau disease: rare or not investigated? Acta Neurochir (Wien) 2001;143:1059–63. 9. Abou-Hamden A, Koszyca B, Carney PG, et al. Metastasis of renal cell carcinoma to haemangioblastoma of the spinal cord in von Hippel-Lindau disease: case report and review of the literature. Pathology 2003;35:224–7. 10. Altinoz MA, Santaguida C, Guiot MC, et al. Spinal hemangioblastoma containing metastatic renal cell carcinoma in von Hippel-Lindau disease. Case report and review of the literature. J Neurosurg Spine 2005;3:495–500. 11. Polydorides AD, Rosenblum MK, Edgar MA. Metastatic renal cell carcinoma to hemangioblastoma in von Hippel-Lindau disease. Arch Pathol Lab Med 2007;131:641–5. 12. Clelland CA, Treip CS. Histological differentiation of metastatic renal carcinoma in the cerebellum from cerebellar haemangioblastoma in von Hippel-Lindau’s disease. J Neurol Neurosurg Psychiatry 1989;52:162–6. 13. Roy S, Chu A, Trojanowski JQ, et al. D2–40, a novel monoclonal antibody against the M2A antigen as a marker to distinguish hemangioblastomas from renal cell carcinomas. Acta Neuropathol 2005;109:497–502.
doi:10.1016/j.jocn.2009.12.027
Impaired vision associated with a solitary intracranial plasmacytoma Xiaoyun Cao a, Shihai Luan a, Linlin Sun b, Bojie Yang a, Chao Shen a, Weimin Bao a,* a b
Department of Neurosurgery, Huashan Hospital of Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China Department of Radiology, Huashan Hospital of Fudan University, Shanghai, China
a r t i c l e
i n f o
Article history: Received 23 November 2009 Accepted 29 December 2009
Keywords: Extramedullary plasmacytoma Intracranial plasmacytoma Plasma cell tumor Solitary intracranial plasmacytoma Neurosurgery Radiotherapy
a b s t r a c t Solitary intracranial plasmacytomas (SICPs) are extremely uncommon tumors in the central nervous system, and are often misdiagnosed pre-operatively. We report a patient with SICP, describe the neuroradiological and neurosurgical features and the clinical management of this patient, and review the pertinent literature. Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved.
1. Case report A 59-year-old man with a 2-month history of impaired vision was admitted to hospital; nothing remarkable was found in his past history. A neurological examination revealed temporal hemianopsia in his left eye, while his right eye only possessed light perception; his cranial nerve examination was normal. Routine blood and urine tests, endocrine profile, a skeletal survey and an examination of a bone marrow aspirate were all unremarkable. A CT scan of the head revealed an intrasellar and intrasphenoidal-sinus lesion, which had eroded the anterior clinoid process and clivus bone. The mass had also partially occluded the suprasellar cistern, and compressed the anterior parts of the third ventricle * Corresponding author. Tel.: +86 21 6248 9999; fax: +86 21 5030 1919. E-mail address: [email protected] (W. Bao).
and lateral ventricle. An MRI scan revealed a large mass located in the sellar region and sphenoidal sinus, with a hypointense signal intensity on T1-weighted images and significant enhancement after administration of gadolinium-diethylenetriamine penta-acetic acid (GD-DTPA) (Fig. 1). Furthermore, the intracranial lesion was solitary on a full-body positron emission tomography (PET)/ CT scan. Pre-operatively, the preliminary diagnosis was a chordoma. Using a transsphenoidal approach, the mass was subtotally resected. During the resection, it was observed that the lesion was soft, fleshy and highly vascular, with a poorly defined border, which involved the bone and dura. A hematoxylin and eosin stain of the resected sample demonstrated typical plasma cells. Immunohistochemical stains revealed the cells were kappa positive (+), lambda negative, and CD79a+; the MIB-1 index of the tumor was 20% (Fig. 2).
1216
Case Reports / Journal of Clinical Neuroscience 17 (2010) 1215–1217
Fig. 1. (a) Coronal head CT scan revealing an intrasellar and intrasphenoidal-sinus lesion, eroding the anterior clinoid processes and clivus. (b) Coronal T1-weighted MRI scan showing a hypointense signal intensity mass. (c) Sagittal T1-weighted contrast enhanced MRI, the lesion is significantly enhanced by gadolinium-diethylenetriamine pentaacetic acid (GD-DTPA).
Fig. 2. Histological examination of the resected tumor sample showing (a) typical plasma cells (hematoxylin and eosin, original magnification 400), (b) immunoglobulin light chains (blue cells), confirming kappa restriction (immunoperoxidase), (c) positive staining for CD79a (immunoperoxidase) and (d) a MIB-1 index of 20% (immunoperoxidase). (This figure is available in colour at www.sciencedirect.com.)
Post-operatively, the patient’s vision was slightly improved. He received 60 Gy of radiotherapy, and it was recommended that follow-up MRI scans should be taken. 2. Discussion Plasma cell tumors, may occur in multiple myeloma (MM), as solitary bone plasmacytomas or as extramedullary plasmacytomas. Extramedullary plasmacytomas, which occur in extraosseous sites, account for 3% of plasma cell neoplasms. Solitary intracranial plasmacytoma (SICP), a rare form of extramedullary plasmacytoma, generally arises from lesions of the dura, leptomeninges or parenchyma, but may involve the cranial vault, skull base, orbits, nasal cavity, paranasal sinuses, meninges and brain. We describe a patient with a SICP and review the related literature. We found 39 cases of SICP reported in the literature.1–3 Most patients were male. This tumor may occur at any age, but is mostly seen in patients in their fifties or sixties. The clinical and neuroradiological findings are generally non-specific, so SICPs are often misdiagnosed pre-operatively. In 1954, Clarke divided cranial myelomas into three clinical groups: (i) group I, which usually involve the skull base but do
not involve the brain parenchyma, and with which cranial nerve palsies are often seen; (ii) group II, which involve the brain parenchyma, with or without origin from the skull; and (iii) group III, which are intra-orbital tumors.4 Our patient had a group I tumor being an intracranial tumor compressing the optical nerve and invading into the skull base, without involvement of the brain parenchyma. The clinical characteristics of SICPs are determined by the location and size of the neoplasm. Raised intracranial pressure, confusion, cranial nerve palsies and seizures are commonly seen in patients whose lesions are located in the cranial vault and the skull base. Involvement of the orbits may result in orbital pain and exophthalmos. Diplopia may result both from the direct effect of an orbital plasmacytoma or from ophthalmoplegia caused by cranial nerve involvement, commonly in the cavernous sinus. Patients with leptomeningeal masses frequently present with paraparesis. On non-enhanced CT scans, the extra-axial SICPs generally appear hyperdense. CT is better than MRI scan in delineating subtle bone erosions. On MRI scan, an intracranial plasmacytoma commonly demonstrates iso- to hypointense signal on T1-weighted images, and an iso- to hyperintense signal on T2-weighted images. On both CT and MRI scans, there may be mild to significant
Case Reports / Journal of Clinical Neuroscience 17 (2010) 1217–1219
enhancement. Restricted diffusion may be seen in diffusionweighted imaging and apparent diffusion coefficient maps. Generally, SICPs may appear similar to meningioma, metastasis, lymphoma, dural sarcoma, plasma cell granuloma, infectious meningitis and leptomeningeal carcinomatosis on imaging, thus they have no specific neuroradiological features. This should be taken into account in the differential diagnosis. The confirmation of a SICP relies on histopathological results and a thorough investigation to exclude the presence of neoplasms elsewhere in the body, including systemic MM. The accepted treatment of SICP is complete or subtotal resection followed by at least 50 Gy radiotherapy.1 Our patient was treated with radiotherapy and will receive follow-up MRI scans. Patients with SICP have more favorable outcomes than those with systemic MM therefore it is prognostically significant to
1217
determine whether a plasmacytoma is solitary. Subtotal or radical resection combined with radiotherapy may result in a favorable remission. References 1. Vujovic O, Fisher BJ, Munoz DG. Solitary intracranial plasmacytoma: case report and review of management. J Neurooncol 1998;39:47–50. 2. Cakir E, Karaarslan G, Usul H, et al. Solitary plasmacytoma with intracranial intraorbital and, paranasal sinus extension. J Clin Neurosci 2003;10:266–8. 3. Brannan SO, Matthews BN, Savant V, et al. Solitary intracranial extra-osseous plasmacytoma presenting with ophthalmic signs. J Neuroophthalmol 2003;23:268–71. 4. Clarke E. Cranial and intracranial myelomas. Brain 1954;77:61–81.
doi:10.1016/j.jocn.2009.12.023
An electrophysiological study of the intermediate syndrome of organophosphate poisoning Paulo José Lorenzoni, Juliano Gasparetto, Cláudia Suemi Kamoi Kay, Rosana Herminia Scola *, Lineu César Werneck Division of Neurology, Department of Internal Medicine, Hospital de Clínicas da Universidade Federal do Paraná (UFPR), Rua General Carneiro 181, Curitiba PR 80060-900, Brazil
a r t i c l e
i n f o
Article history: Received 11 September 2009 Accepted 22 November 2009
Keywords: Electrophysiological study Intermediate syndrome Organophosphate poisoning Repetitive nerve stimulation
a b s t r a c t Acute organophosphate (OP) poisoning is commonly seen in emergency medicine. Neurologists must be alert to detect neuromuscular transmission failure and other neurological complications that follow OP poisoning. We report a 37-year-old male with acute OP poisoning to emphasize the electrophysiological abnormalities during the intermediate syndrome (IMS). Motor nerve conduction studies revealed that a single nerve stimulation evoked a repetitive compound muscle action potential, whereas repetitive nerve stimulation resulted in a combination of a decrement–increment pattern and a repetitive fade response. Thus, electrophysiological studies can be used to monitor patients with IMS, and these test results correlate well with clinical findings in acute OP poisoning. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction The organophosphates (OP) comprise a large group of compounds that have the potential to irreversibly inhibit cholinesterase, acetylcholinesterase (AChE) and target nerve esterase.1,2 OP poisoning leads to three main clinical syndromes: (i) acute cholinergic syndrome; (ii) intermediate syndrome (IMS); and (iii) peripheral neuropathy.2–4 In 1957, Senanayake and Karalliedde described a syndrome of muscular paralysis that occurred in awake patients 24 hours to 96 hours after a cholinergic syndrome caused by OP ingestion that had been treated with atropine.3,5 This syndrome usually follows acute cholinergic syndrome and precedes a delayed neuropathy; thus, it is referred to as the ‘‘intermediate syndrome”. IMS has been noted late in the course of cholinergic syndrome in several patients, and is marked by weakness and fatigue of skeletal muscles with fasciculation leading to respiratory muscle paralysis.1–6
* Corresponding author. Tel.: +55 41 33601800; fax: +55 41 32430182. E-mail address: [email protected] (R.H. Scola).
A diagnosis of OP poisoning is based on the characteristic clinical features and history of exposure to a known OP compound.1 The concentration of serum OP may be tested in patients suspected of OP exposure; however, serum cholinesterase level and electrophysiological studies are helpful in confirming the diagnosis.1,3 Acute OP poisoning is important in emergency medicine in many underdeveloped countries.1,4 Neurologists working in these countries must be alert to detect neuromuscular transmission failure and other neurologic complications that follow OP poisoning.1,7,8 We report a patient with acute OP poisoning to highlight the electrophysiological abnormalities observed during IMS. 2. Case report A 37-year-old male was referred to our hospital 12 hours after the ingestion of an unknown poison. He presented with swallowing difficulties and increased perspiration and oral and bronchial secretions. Physical examination showed bradycardia, hypotension, conjunctival hyperemia and miosis (pinpoint pupils), and revealed the patient to be in a stupor. The clinical features were thought to be consistent with acute OP poisoning. A reduction of