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Vanishing Brainstem Edema
Case Report
Vanishing Brainstem Edema Mark O. McCarron, MA, MD, FRCP,* and C. Steven McKinstry, FRCR†
Posterior reversible encephalopathy syndrome caused by hypertension is well recognized with magnetic resonance imaging. We report a patient in whom posterior reversible encephalopathy syndrome involved just the brainstem, caused a pontine stroke, and subsequently both clinically and radiologically improved with antihypertensive therapy. Key Words: Pontine infarct—posterior reversible encephalopathy syndrome. Ó 2008 by National Stroke Association
Clinical and radiologic recognition of posterior reversible encephalopathy syndrome (PRES) can prevent devastating neurologic sequelae. We report a patient with a hypertensive brainstem variant of PRES complicated by stroke.
Case Report A 42-year-old man was admitted to hospital after a tonicclonic seizure. He took no medication and drank no alcohol, but smoked hand-rolled cigarettes. On admission, he was hypertensive at 195/115 mm Hg. He was irritable and had slurred speech. Neurologic examination demonstrated intact cognition, hyperreflexia, a mild right hemiparesis with ataxia, and a right extensor plantar response. Magnetic resonance imaging (MRI) of brain showed diffusely increased signal in the brainstem with a focal area of higher signal in the left pons on T2-weighted imaging (Fig 1, A and B) consistent with infarction and brainstem edema. Full blood cell count, electrolytes, glucose, and hemoglobin A1c were normal. His blood pressure was gradually lowered, ultimately requiring 5 antihypertensive drugs (atenolol, bendroflumethiazide, perindopril, From the *Department of Neurology, Altnagelvin Hospital, Londonderry, and †Department of Neuoradiology, Royal Victoria Hospital, Belfast, United Kingdom. Received September 25, 2007; revision received December 4, 2007; accepted December 19, 2007. Address correspondence to Mark O. McCarron, MA, MD, FRCP, Department of Neurology, Altnagelvin Hospital, Londonderry BT47 6SB United Kingdom. E-mail: [email protected]. 1052-3057/$—see front matter Ó 2008 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2007.12.006
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nifedipine, and doxazosin) reaching 140/93 mm Hg within 15 days. Renal ultrasound and electrocardiography results were normal. Transthoracic echocardiography showed left ventricular hypertrophy. Urinary catecholamines were unremarkable. Clinically he stabilized, but he was left with a residual right-sided ataxia and mild dysarthria. Follow-up MRI scan at 3 months (Fig 1, C and D) showed almost complete resolution of the diffuse signal change in the brainstem, but residual focal areas of infarction. His blood pressure was 135/85 mm Hg.
Discussion PRES is a disorder of cerebral autoregulation and endothelial function leading to vasogenic edema.1 The syndrome has also been associated with immunosuppressive drugs and renal insufficiency.2 Improvements in managing blood pressure have decreased mortality from the hypertensive form of PRES. Endothelial damage or dysfunction may cause loss of autoregulation and increased capillary permeability, possibly via increased production of nitric oxide. An increase in blood pressure, often in patients who have no history of chronic hypertension, is the most frequently recognized cause. Because of the nonspecific clinical features at presentation, which include headache, confusion, visual disturbance and seizures, the diagnosis is often made by radiologists. We suspect that our patient’s right hemiparesis, ataxia, and extensor plantar response were caused by pontine infarction, whereas his initial seizure, irritability, and bilateral hyperreflexia were a result of brainstem PRES. It could, however, be argued that PRES only became symptomatic by causing pontine infarction. Diffusion-weighted
Journal of Stroke and Cerebrovascular Diseases, Vol. 17, No. 3 (May-June), 2008: pp 156-157
BRAINSTEM EDEMA
157
Figure 1. Sagittal (A) and axial (B) T2-weighted MRI of brain showing diffuse high signal throughout brainstem and focal area of higher signal in pons. Subsequent imaging at 3 months (C and D) shows almost complete resolution of diffuse high signal but small pontine areas of high signal consistent with infarction.
MRI and anisotropy diffusion studies suggest that transient vasogenic edema causes the MRI signal change. Brainstem and deep white matter involvement have less reversibility than cortical and other subcortical areas.3 A relative decrease in sympathetic innervation in the vertebrobasilar system compared with the anterior circulation is thought to make posterior fossa structures relatively more vulnerable to PRES than other brain structures in the presence of elevated systemic blood pressures.4 MRI has increased the recognition of PRES, but the brainstem variant has rarely been reported.5-7
References 1. Lamy C, Oppenheim C, Me´der JF, et al. Neuroimaging in posterior reversible encephalopathy syndrome. J Neuroimaging 2004;14:89-96.
2. Hinchey J, Chaves C, Appignani B, et al. A reversible posterior leukoencephalopathy syndrome. N Engl J Med 1996; 334:494-500. 3. Pande AR, Ando K, Ishikura R, et al. Clinicoradiological factors influencing the reversibility of posterior reversible encephalopathy syndrome: A multicenter study. Radiat Med 2006;24:659-668. 4. Schwartz RB. Hyperperfusion encephalopathies: Hypertensive encephalopathy and related conditions. Neurologist 2002;8:22-34. 5. Kitaguchi H, Tomimoto H, Miki Y, et al. A brainstem variant of reversible posterior leukoencephalopathy syndrome. Neuroradiology 2005;47:652-656. 6. Yasuda Y, Akiguchi I, Imai T, et al. Hypertensive brainstem encephalopathy. Intern Med 2003;42:11311134. 7. Fong CS. Hypertensive encephalopathy involving the brainstem and deep structures: A case report. Acta Neurol Taiwan 2005;14:191-194.
Vanishing Brainstem Edema Mark O. McCarron, MA, MD, FRCP,* and C. Steven McKinstry, FRCR†
Posterior reversible encephalopathy syndrome caused by hypertension is well recognized with magnetic resonance imaging. We report a patient in whom posterior reversible encephalopathy syndrome involved just the brainstem, caused a pontine stroke, and subsequently both clinically and radiologically improved with antihypertensive therapy. Key Words: Pontine infarct—posterior reversible encephalopathy syndrome. Ó 2008 by National Stroke Association
Clinical and radiologic recognition of posterior reversible encephalopathy syndrome (PRES) can prevent devastating neurologic sequelae. We report a patient with a hypertensive brainstem variant of PRES complicated by stroke.
Case Report A 42-year-old man was admitted to hospital after a tonicclonic seizure. He took no medication and drank no alcohol, but smoked hand-rolled cigarettes. On admission, he was hypertensive at 195/115 mm Hg. He was irritable and had slurred speech. Neurologic examination demonstrated intact cognition, hyperreflexia, a mild right hemiparesis with ataxia, and a right extensor plantar response. Magnetic resonance imaging (MRI) of brain showed diffusely increased signal in the brainstem with a focal area of higher signal in the left pons on T2-weighted imaging (Fig 1, A and B) consistent with infarction and brainstem edema. Full blood cell count, electrolytes, glucose, and hemoglobin A1c were normal. His blood pressure was gradually lowered, ultimately requiring 5 antihypertensive drugs (atenolol, bendroflumethiazide, perindopril, From the *Department of Neurology, Altnagelvin Hospital, Londonderry, and †Department of Neuoradiology, Royal Victoria Hospital, Belfast, United Kingdom. Received September 25, 2007; revision received December 4, 2007; accepted December 19, 2007. Address correspondence to Mark O. McCarron, MA, MD, FRCP, Department of Neurology, Altnagelvin Hospital, Londonderry BT47 6SB United Kingdom. E-mail: [email protected]. 1052-3057/$—see front matter Ó 2008 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2007.12.006
156
nifedipine, and doxazosin) reaching 140/93 mm Hg within 15 days. Renal ultrasound and electrocardiography results were normal. Transthoracic echocardiography showed left ventricular hypertrophy. Urinary catecholamines were unremarkable. Clinically he stabilized, but he was left with a residual right-sided ataxia and mild dysarthria. Follow-up MRI scan at 3 months (Fig 1, C and D) showed almost complete resolution of the diffuse signal change in the brainstem, but residual focal areas of infarction. His blood pressure was 135/85 mm Hg.
Discussion PRES is a disorder of cerebral autoregulation and endothelial function leading to vasogenic edema.1 The syndrome has also been associated with immunosuppressive drugs and renal insufficiency.2 Improvements in managing blood pressure have decreased mortality from the hypertensive form of PRES. Endothelial damage or dysfunction may cause loss of autoregulation and increased capillary permeability, possibly via increased production of nitric oxide. An increase in blood pressure, often in patients who have no history of chronic hypertension, is the most frequently recognized cause. Because of the nonspecific clinical features at presentation, which include headache, confusion, visual disturbance and seizures, the diagnosis is often made by radiologists. We suspect that our patient’s right hemiparesis, ataxia, and extensor plantar response were caused by pontine infarction, whereas his initial seizure, irritability, and bilateral hyperreflexia were a result of brainstem PRES. It could, however, be argued that PRES only became symptomatic by causing pontine infarction. Diffusion-weighted
Journal of Stroke and Cerebrovascular Diseases, Vol. 17, No. 3 (May-June), 2008: pp 156-157
BRAINSTEM EDEMA
157
Figure 1. Sagittal (A) and axial (B) T2-weighted MRI of brain showing diffuse high signal throughout brainstem and focal area of higher signal in pons. Subsequent imaging at 3 months (C and D) shows almost complete resolution of diffuse high signal but small pontine areas of high signal consistent with infarction.
MRI and anisotropy diffusion studies suggest that transient vasogenic edema causes the MRI signal change. Brainstem and deep white matter involvement have less reversibility than cortical and other subcortical areas.3 A relative decrease in sympathetic innervation in the vertebrobasilar system compared with the anterior circulation is thought to make posterior fossa structures relatively more vulnerable to PRES than other brain structures in the presence of elevated systemic blood pressures.4 MRI has increased the recognition of PRES, but the brainstem variant has rarely been reported.5-7
References 1. Lamy C, Oppenheim C, Me´der JF, et al. Neuroimaging in posterior reversible encephalopathy syndrome. J Neuroimaging 2004;14:89-96.
2. Hinchey J, Chaves C, Appignani B, et al. A reversible posterior leukoencephalopathy syndrome. N Engl J Med 1996; 334:494-500. 3. Pande AR, Ando K, Ishikura R, et al. Clinicoradiological factors influencing the reversibility of posterior reversible encephalopathy syndrome: A multicenter study. Radiat Med 2006;24:659-668. 4. Schwartz RB. Hyperperfusion encephalopathies: Hypertensive encephalopathy and related conditions. Neurologist 2002;8:22-34. 5. Kitaguchi H, Tomimoto H, Miki Y, et al. A brainstem variant of reversible posterior leukoencephalopathy syndrome. Neuroradiology 2005;47:652-656. 6. Yasuda Y, Akiguchi I, Imai T, et al. Hypertensive brainstem encephalopathy. Intern Med 2003;42:11311134. 7. Fong CS. Hypertensive encephalopathy involving the brainstem and deep structures: A case report. Acta Neurol Taiwan 2005;14:191-194.