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A splenial lesion with transiently reduced diffusion in clinically mild encephalitis is not always reversible: A case report
Brain & Development 31 (2009) 710–712 www.elsevier.com/locate/braindev
Case report
A splenial lesion with transiently reduced diffusion in clinically mild encephalitis is not always reversible. A case report Yuji Hashimoto a,*, Jun-ichi Takanashi b, Keiko Kaiho a, Katsunori Fujii c, Toshiyuki Okubo a, Setsuo Ota a, Yoichi Kohno c a
Department of Pediatrics and Radiology, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara-shi, Chiba 299-0111, Japan b Department of Pediatrics, Kameda Medical Center, Kamogawa, Japan c Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan Received 29 July 2008; received in revised form 18 September 2008; accepted 19 October 2008
Abstract The MR imaging finding of a reversible splenial lesion with transiently reduced diffusion has been reported in patients with clinically mild encephalitis/encephalopathy, leading to a new clinical-radiological syndrome, clinically mild encephalitis/encephalopathy with a reversible splenial lesion. We recently experienced a 3-year-old boy with clinically mild encephalitis with a splenial lesion exhibiting transient reduced diffusion on admission. He recovered completely with no particular treatment within 2 weeks. Though the splenial lesion decreased in size, it was detected for over 5 months in T2-weighted imaging. It is suggested that a splenial lesion with transiently reduced diffusion in clinically mild encephalitis/encephalopathy is not always reversible, and could result in gliosis. Ó 2008 Elsevier B.V. All rights reserved. Keywords: Encephalitis; Encephalopathy; Corpus callosum; Splenium; Reversible; Gliosis
1. Introduction The MR imaging finding of a reversible lesion with transiently reduced diffusion in the central portion of the splenium of the corpus callosum (SCC) has been reported in patients with clinically mild encephalitis/ encephalopathy, leading to a new clinical-radiological syndrome, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) [1]. In previously reported patients with MERS, the SCC lesions disappeared within a short period. No patient has shown residual T2 prolongation in the SCC, as far as we know. We report here a 3-year-old boy with clinically * Corresponding author. Address: Department of Pediatrics, Chiba Kaihin Municipital Hospital, 3-31-1 Isobe, Mihama-ku, Chiba-shi, Chiba 261-0012, Japan. Tel.: +81 43 277 7711; fax: +81 43 278 7482. E-mail address: [email protected] (Y. Hashimoto).
0387-7604/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.braindev.2008.10.005
mild encephalitis with a splenial lesion, which gradually decreased in size, but was detected for over 5 months. 2. Case report A 3-year-old boy with a clinical history of egg allergy developed a high-grade fever, vomiting and diarrhea for nine days before admission. Antibiotic, antiemetic and antidiarrheal medications were prescribed by a local doctor. He was transferred to our hospital because of getting drowsiness. Physical examination on admission revealed a body temperature of 36.6 °C, a pulse rate of 126/min and a blood pressure of 106/80 mmHg. He presented with drowsiness (Glasgow coma scale; E3, V1, M4) with slight up-deviation in the eyeballs and hypotonus. His blood count and biochemical examinations were normal except for decreased sodium (129 mmol/ l), increased uric acid (8.1 mg/dl), and increased blood
Y. Hashimoto et al. / Brain & Development 31 (2009) 710–712
ketone (4364 mmol/l). Cerebrospinal fluid (CSF) showed an increased cell count (44 cells/mm3, polymorphonuclear/mononuclear = 8/36) and slightly increased protein (54 mg/dl), but a normal glucose level. Brain CT was normal. Electroencephalography showed diffuse high-voltage slow waves. Thus, a diagnosis of encephalitis was made. MR imaging was performed on the first hospital day. T2-weighted images showed hyperintense SCC lesions, extending irregularly into the lateral portion of the SCC. Diffusion-weighted images (DWI) showed marked hyperintensity in the lesion with reduced diffusion (an apparent diffusion coefficient [ADC] value for SCC = 0.481 10 3 mm2/s) (Fig. 1). He had not taken any oral antiepileptic drug. We tentatively diagnosed the patient as having MERS. As treatment, we administered acyclovir till herpes simplex virus infection was ruled out, and restricted water intake because a possible diagnosis of syndrome of inappropriate secretion of antidiuretic hormone (SIADH), based on a low sodium level of 125 mmol/l with a relatively high urine sodium secretion level of 170 mmol/l and an antidiuretic hormone one of 3.7 pg/ml. Corticosteroids were not administered. He gradually improved and completely recovered without sequelae within two weeks. The Tanaka-Binet Intelligence Scale score was IQ 93 on day 45. No pathogen was found in his stool, blood and CSF samples. Follow-up MR imaging studies were performed five times on hospital days 4, 15, 29, 57, and 154. T2-
711
weighted axial and sagittal images showed an extensive SCC lesion within a month. Afterwards, the SCC lesion gradually decreased in size, but was still detectable on day 154. The ADC map showed no reduced diffusion after day 4. Thus, the hyperintensity seen on DWI should have resulted from the T2 shine-through effect (Fig. 2). 3. Discussion Twenty-eight patients with MERS were previously reported [1–10]. The SCC abnormalities in all 28 patients had completely disappeared at the time of follow-up MRI studies performed from 3 days to 3-months (most often within 1 week, i.e. 14 of 28 patients) after the first abnormal results. Recently, reversible lesions with transiently reduced diffusion have also been reported with lateral extension from the splenium into the frontoparietal subcortical white matter [11], and with anterior extension to involve the entire corpus callosum [12], suggesting MERS has a wider spectrum than previously considered. These accompanying lesions also disappear within a short period. In the present patient, the MRI finding of an isolated splenial lesion exhibiting homogenously and transiently reduced diffusion with clinically mild encephalitis was identical to those reported in MERS. It was, therefore, reasonable to make a tentative diagnosis of MERS for this patient. However, it was atypical in that the SCC
Fig. 1. MR imaging on the first hospital day, showing hyperintensity extending irregularly into the lateral portion of the SCC in T2-weighted images (B) and slight hypointensity in T1-weighted images (A). Diffusion-weighted images (DWI) showed markedly hyperintensity in the lesion (C) and an apparent diffusion coefficient (ADC) map showed reduced diffusion (ADC value for SCC = 0.481 10 3 mm2/s) (D).
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Y. Hashimoto et al. / Brain & Development 31 (2009) 710–712
Fig. 2. Expansion of the splenium of the corpus callosum (SCC) lesion in T2-weighted images (T2WI), Diffusion-weighted images (DWI) and an apparent diffusion coefficient (ADC) on hospital days 4 (A), 29 (B), and 154 (C). The SCC lesion in T2WI gradually decreased in size, but could still be detected on day 154. ADC values for SCC were 0.566 10 3 mm2/s (A) on day 4, 0.843 10 3 mm2/s (B) on day 29, and 1.020 10 3 mm2/s (C) on day 154, respectively.
lesion was detectable for more than 5 months. The reason for transiently reduced diffusion within the splenial lesions in MERS remains unknown; possibilities include intramyelinic edema, interstitial edema in tightly packed fibers, and a transient inflammatory infiltrate [1,13]. In any case, the T2 prolongation with increased diffusion in the SCC seen on follow-up MRI (ADC value for SCC, 1.020 10 3 mm2/s on day 154) in this patient raises the possibility that a splenial lesion with reduced diffusion could result in gliosis. Clearly, further studies of patients with clinically mild encephalitis/encephalopathy with a persistent splenial lesion will be necessary to determine if the description of the neuroradiological findings in MERS should be revised.
Acknowledgement This study was supported in part by the Research Grant (20A-14) for Nervous and Mental Disorders from the Ministry of Health, Labor and Welfare of Japan; and by the Japan Epilepsy Research Foundation. References [1] Tada H, Takanashi J, Barkovich AJ, Oba H, Maeda M, Tsukahara H, et al. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion. Neurology 2004;63:1854–8. [2] Ogura H, Takaoka M, Kishi M, Kimoto M, Shimazu T, Yoshioka T, et al. Reversible MR findings of hemolytic uremic syndrome with mild encephalopathy. AJNR Am J Neuroradiol 1998;19:1144–5.
[3] Kobata R, Tsukahara H, Nakai A, Tanizawa A, Ishimori Y, Kawamura Y, et al. Transient MR signal changes in the splenium of the corpus callosum in rotavirus encephalopathy: value of diffusion-weighted imaging. J Comput Assist Tomogr 2002;26:825–8. [4] Takanashi J, Barkovich AJ, Yamaguchi K, Kohno Y. Influenzaassociated encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum: a case report and literature review. AJNR Am J Neuroradiol 2004;25:798–802. [5] Morgan JC, Cavaliere R, Juel VC. Reversible corpus callosum lesion in legionnaires’ disease. J Neurol Neurosurg Psychiatry 2004;75:651–4. [6] Yeh IB, Tan CS, Sitoh YY. Reversible splenial lesion in clinically mild encephalitis. Singapore Med J 2005;46:726–30. [7] Bulakbasi N, Kocaoglu M, Tayfun C, Ucoz T. Transient splenial lesion of the corpus callosum in clinically mild influenza-associated encephalitis/encephalopathy. AJNR Am J Neuroradiol 2006;27:1983–6. [8] Hong JM, Joo IS. A case of isolated and transient splenial lesion of the corpus callosum associated with disseminated Staphylococcus aureus infection. J Neurol Sci 2006;250:156–8. [9] Maeda M, Tsukahara H, Terada H, Nakaji S, Nakamura H, Oba H, et al. Reversible splenial lesion with restricted diffusion in a wide spectrum of diseases and conditions. J Neuroradiol 2006;33:229–36. [10] Matsubara K, Kodera M, Nigami H, Yura K, Fukaya T. Reversible splenial lesion in influenza virus encephalopathy. Pediatr Neurol 2007;37:431–4. [11] Takanashi J, Barkovich AJ, Shiihara T, Tada H, Kawatani M, Tsukahara H, et al. Widening spectrum of a reversible splenial lesion with transiently reduced diffusion. AJNR Am J Neuroradiol 2006;27:836–8. [12] Takanashi J, Hirasawa K, Tada H. Reversible restricted diffusion of entire corpus callosum. J Neurol Sci 2006;247:101–4. [13] Doherty MJ, Jayadev S, Watson NF, Konchada RS, Hallam DK. Clinical implications of splenium magnetic resonance imaging signal changes. Arch Neurol 2005;62:433–7.
Case report
A splenial lesion with transiently reduced diffusion in clinically mild encephalitis is not always reversible. A case report Yuji Hashimoto a,*, Jun-ichi Takanashi b, Keiko Kaiho a, Katsunori Fujii c, Toshiyuki Okubo a, Setsuo Ota a, Yoichi Kohno c a
Department of Pediatrics and Radiology, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara-shi, Chiba 299-0111, Japan b Department of Pediatrics, Kameda Medical Center, Kamogawa, Japan c Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan Received 29 July 2008; received in revised form 18 September 2008; accepted 19 October 2008
Abstract The MR imaging finding of a reversible splenial lesion with transiently reduced diffusion has been reported in patients with clinically mild encephalitis/encephalopathy, leading to a new clinical-radiological syndrome, clinically mild encephalitis/encephalopathy with a reversible splenial lesion. We recently experienced a 3-year-old boy with clinically mild encephalitis with a splenial lesion exhibiting transient reduced diffusion on admission. He recovered completely with no particular treatment within 2 weeks. Though the splenial lesion decreased in size, it was detected for over 5 months in T2-weighted imaging. It is suggested that a splenial lesion with transiently reduced diffusion in clinically mild encephalitis/encephalopathy is not always reversible, and could result in gliosis. Ó 2008 Elsevier B.V. All rights reserved. Keywords: Encephalitis; Encephalopathy; Corpus callosum; Splenium; Reversible; Gliosis
1. Introduction The MR imaging finding of a reversible lesion with transiently reduced diffusion in the central portion of the splenium of the corpus callosum (SCC) has been reported in patients with clinically mild encephalitis/ encephalopathy, leading to a new clinical-radiological syndrome, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) [1]. In previously reported patients with MERS, the SCC lesions disappeared within a short period. No patient has shown residual T2 prolongation in the SCC, as far as we know. We report here a 3-year-old boy with clinically * Corresponding author. Address: Department of Pediatrics, Chiba Kaihin Municipital Hospital, 3-31-1 Isobe, Mihama-ku, Chiba-shi, Chiba 261-0012, Japan. Tel.: +81 43 277 7711; fax: +81 43 278 7482. E-mail address: [email protected] (Y. Hashimoto).
0387-7604/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.braindev.2008.10.005
mild encephalitis with a splenial lesion, which gradually decreased in size, but was detected for over 5 months. 2. Case report A 3-year-old boy with a clinical history of egg allergy developed a high-grade fever, vomiting and diarrhea for nine days before admission. Antibiotic, antiemetic and antidiarrheal medications were prescribed by a local doctor. He was transferred to our hospital because of getting drowsiness. Physical examination on admission revealed a body temperature of 36.6 °C, a pulse rate of 126/min and a blood pressure of 106/80 mmHg. He presented with drowsiness (Glasgow coma scale; E3, V1, M4) with slight up-deviation in the eyeballs and hypotonus. His blood count and biochemical examinations were normal except for decreased sodium (129 mmol/ l), increased uric acid (8.1 mg/dl), and increased blood
Y. Hashimoto et al. / Brain & Development 31 (2009) 710–712
ketone (4364 mmol/l). Cerebrospinal fluid (CSF) showed an increased cell count (44 cells/mm3, polymorphonuclear/mononuclear = 8/36) and slightly increased protein (54 mg/dl), but a normal glucose level. Brain CT was normal. Electroencephalography showed diffuse high-voltage slow waves. Thus, a diagnosis of encephalitis was made. MR imaging was performed on the first hospital day. T2-weighted images showed hyperintense SCC lesions, extending irregularly into the lateral portion of the SCC. Diffusion-weighted images (DWI) showed marked hyperintensity in the lesion with reduced diffusion (an apparent diffusion coefficient [ADC] value for SCC = 0.481 10 3 mm2/s) (Fig. 1). He had not taken any oral antiepileptic drug. We tentatively diagnosed the patient as having MERS. As treatment, we administered acyclovir till herpes simplex virus infection was ruled out, and restricted water intake because a possible diagnosis of syndrome of inappropriate secretion of antidiuretic hormone (SIADH), based on a low sodium level of 125 mmol/l with a relatively high urine sodium secretion level of 170 mmol/l and an antidiuretic hormone one of 3.7 pg/ml. Corticosteroids were not administered. He gradually improved and completely recovered without sequelae within two weeks. The Tanaka-Binet Intelligence Scale score was IQ 93 on day 45. No pathogen was found in his stool, blood and CSF samples. Follow-up MR imaging studies were performed five times on hospital days 4, 15, 29, 57, and 154. T2-
711
weighted axial and sagittal images showed an extensive SCC lesion within a month. Afterwards, the SCC lesion gradually decreased in size, but was still detectable on day 154. The ADC map showed no reduced diffusion after day 4. Thus, the hyperintensity seen on DWI should have resulted from the T2 shine-through effect (Fig. 2). 3. Discussion Twenty-eight patients with MERS were previously reported [1–10]. The SCC abnormalities in all 28 patients had completely disappeared at the time of follow-up MRI studies performed from 3 days to 3-months (most often within 1 week, i.e. 14 of 28 patients) after the first abnormal results. Recently, reversible lesions with transiently reduced diffusion have also been reported with lateral extension from the splenium into the frontoparietal subcortical white matter [11], and with anterior extension to involve the entire corpus callosum [12], suggesting MERS has a wider spectrum than previously considered. These accompanying lesions also disappear within a short period. In the present patient, the MRI finding of an isolated splenial lesion exhibiting homogenously and transiently reduced diffusion with clinically mild encephalitis was identical to those reported in MERS. It was, therefore, reasonable to make a tentative diagnosis of MERS for this patient. However, it was atypical in that the SCC
Fig. 1. MR imaging on the first hospital day, showing hyperintensity extending irregularly into the lateral portion of the SCC in T2-weighted images (B) and slight hypointensity in T1-weighted images (A). Diffusion-weighted images (DWI) showed markedly hyperintensity in the lesion (C) and an apparent diffusion coefficient (ADC) map showed reduced diffusion (ADC value for SCC = 0.481 10 3 mm2/s) (D).
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Y. Hashimoto et al. / Brain & Development 31 (2009) 710–712
Fig. 2. Expansion of the splenium of the corpus callosum (SCC) lesion in T2-weighted images (T2WI), Diffusion-weighted images (DWI) and an apparent diffusion coefficient (ADC) on hospital days 4 (A), 29 (B), and 154 (C). The SCC lesion in T2WI gradually decreased in size, but could still be detected on day 154. ADC values for SCC were 0.566 10 3 mm2/s (A) on day 4, 0.843 10 3 mm2/s (B) on day 29, and 1.020 10 3 mm2/s (C) on day 154, respectively.
lesion was detectable for more than 5 months. The reason for transiently reduced diffusion within the splenial lesions in MERS remains unknown; possibilities include intramyelinic edema, interstitial edema in tightly packed fibers, and a transient inflammatory infiltrate [1,13]. In any case, the T2 prolongation with increased diffusion in the SCC seen on follow-up MRI (ADC value for SCC, 1.020 10 3 mm2/s on day 154) in this patient raises the possibility that a splenial lesion with reduced diffusion could result in gliosis. Clearly, further studies of patients with clinically mild encephalitis/encephalopathy with a persistent splenial lesion will be necessary to determine if the description of the neuroradiological findings in MERS should be revised.
Acknowledgement This study was supported in part by the Research Grant (20A-14) for Nervous and Mental Disorders from the Ministry of Health, Labor and Welfare of Japan; and by the Japan Epilepsy Research Foundation. References [1] Tada H, Takanashi J, Barkovich AJ, Oba H, Maeda M, Tsukahara H, et al. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion. Neurology 2004;63:1854–8. [2] Ogura H, Takaoka M, Kishi M, Kimoto M, Shimazu T, Yoshioka T, et al. Reversible MR findings of hemolytic uremic syndrome with mild encephalopathy. AJNR Am J Neuroradiol 1998;19:1144–5.
[3] Kobata R, Tsukahara H, Nakai A, Tanizawa A, Ishimori Y, Kawamura Y, et al. Transient MR signal changes in the splenium of the corpus callosum in rotavirus encephalopathy: value of diffusion-weighted imaging. J Comput Assist Tomogr 2002;26:825–8. [4] Takanashi J, Barkovich AJ, Yamaguchi K, Kohno Y. Influenzaassociated encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum: a case report and literature review. AJNR Am J Neuroradiol 2004;25:798–802. [5] Morgan JC, Cavaliere R, Juel VC. Reversible corpus callosum lesion in legionnaires’ disease. J Neurol Neurosurg Psychiatry 2004;75:651–4. [6] Yeh IB, Tan CS, Sitoh YY. Reversible splenial lesion in clinically mild encephalitis. Singapore Med J 2005;46:726–30. [7] Bulakbasi N, Kocaoglu M, Tayfun C, Ucoz T. Transient splenial lesion of the corpus callosum in clinically mild influenza-associated encephalitis/encephalopathy. AJNR Am J Neuroradiol 2006;27:1983–6. [8] Hong JM, Joo IS. A case of isolated and transient splenial lesion of the corpus callosum associated with disseminated Staphylococcus aureus infection. J Neurol Sci 2006;250:156–8. [9] Maeda M, Tsukahara H, Terada H, Nakaji S, Nakamura H, Oba H, et al. Reversible splenial lesion with restricted diffusion in a wide spectrum of diseases and conditions. J Neuroradiol 2006;33:229–36. [10] Matsubara K, Kodera M, Nigami H, Yura K, Fukaya T. Reversible splenial lesion in influenza virus encephalopathy. Pediatr Neurol 2007;37:431–4. [11] Takanashi J, Barkovich AJ, Shiihara T, Tada H, Kawatani M, Tsukahara H, et al. Widening spectrum of a reversible splenial lesion with transiently reduced diffusion. AJNR Am J Neuroradiol 2006;27:836–8. [12] Takanashi J, Hirasawa K, Tada H. Reversible restricted diffusion of entire corpus callosum. J Neurol Sci 2006;247:101–4. [13] Doherty MJ, Jayadev S, Watson NF, Konchada RS, Hallam DK. Clinical implications of splenium magnetic resonance imaging signal changes. Arch Neurol 2005;62:433–7.