Case Report
Bilateral Medial Medullary Infarction with Nondominant Vertebral Artery Occlusion Lei Zhang, MS,* Gui-lian Zhang, PhD,† Ju-mei Du, MSc,* and Zhu-lin Ma, MSc†
Bilateral medial medullary infarction (MMI) is a rare stroke subtype. Here, we report a case with bilateral MMI caused by nondominant vertebral artery occlusion confirmed by brain digital subtraction angiography and magnetic resonance imaging basi-parallel-anatomical-scanning. We highlight that anterior spinal arteries could originate from a unilateral vertebral artery (VA). Radiologists and neurologists should pay attention to the nondominant VA as bilateral MMI may be induced by occlusion of nondominant VA that supplies the bilateral anteromedial territories of the medulla. Key Words: Bilateral medial medullary infarction—nondominant vertebral artery—stroke—MRI-BPAS. Ó 2015 by National Stroke Association
Introduction Medial medullary infarction (MMI) is a rare stroke subtype, account for only .5%-1.5% of all strokes, whereas bilateral MMI is even rarer.1 Although there are some previous reports of bilateral MMI, bilateral MMI caused by nondominant vertebral artery (VA) occlusion confirmed by brain digital subtraction angiography (DSA) is very uncommon.
Case Report A 48-year-old man was taken to our hospital with weakness in 4 limbs and slurred speech that started From the *Department of Neurology, The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, Shaanxi Province; and †Department of Neurology, The Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xi’an, Shaanxi Province, China. Received October 24, 2014; revision received February 7, 2015; accepted April 3, 2015. Address correspondence to Gui-lian Zhang, PhD, Department of Neurology, The Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, No. 157 West 5 Road, Xi’an 710004, Shaanxi Province, China. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2015 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.04.005
5 hours prior. According to the patient’s family, the patient was at home when he felt mild weakness in his right upper limb and right lower limb, which progressively worsened into tetraplegia within a few minutes, with slurred speech, dysphagia, and irritating cough due to reflux of liquids. The patient had a history of hypertension and cigarette smoking. Neurologic examination revealed breathing difficulty, dysarthria, hyporeflexia, quadriplegia, and bilateral extensor plantar reflexes. The power in his 4 limbs was 0 of 5. The National Institutes of Health Stroke Scale score was 21. His routine laboratory tests including blood count, renal and hepatic function tests, erythrocyte sedimentation rate, C-reactive protein, and urinary tests were normal. Brain magnetic resonance imaging (MRI) showed a hyperintense ‘‘heart appearance’’ signal in the bilateral anteromedial medullae on axial T2-weighted imaging (Fig 1, A), whereas diffusion-weighted images (DWIs) revealed a corresponding area of restricted diffusion (Fig 1, B). The patient then underwent a brain DSA, which showed no abnormalities in the basilar artery or wholly right VA (Fig 2, A). However, the left VA exhibited wholly slenderer than the right VA in extracranial portion. The left VA showed the nondominant and occlusion in the distal intracranial part (Fig 2, B). The patient was diagnosed with acute bilateral MMI.
Journal of Stroke and Cerebrovascular Diseases, Vol. 24, No. 9 (September), 2015: pp e241-e244
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Figure 1. Brain MRI showed bilateral medial medullary infarction. (A) Axial T2WI image showed a ‘‘heart appearance’’ area of hyperintense signal in the bilateral anteromedial medullae. (B) Axial DWI image showed a ‘‘heart appearance’’ area of restricted diffusion in the medulla. Abbreviations: DWI, diffusion-weighted imaging; T2WI, T2-weighted imaging; MRI, magnetic resonance imaging.
On day 3 of admission, he received a tracheotomy mask because of respiratory distress. At 7 weeks after hospitalization, his slurred speech showed significant improvement. Further, the power was 4 of 5 in the left upper
limb and bilateral lower limb, and 3 of 5 in the right upper limb, the National Institutes of Health Stroke Scale score was 5. At 1 year after onset, his voice was hoarse. The power was almost normal in limbs, but muscle tone still
Figure 2. Brain DSA showed no abnormalities in the right VA and basilar artery, and the right VA was more dominant than the left in extracranial portion, the left VA was occluded at the distal intracranial portion. (A) Basilar artery and intracranial portion of right VA. (B) Extracranial portion of left VA. (C) Extracranial portion of right VA. (D) Extracranial portion of left VA. Abbreviations: DSA, digital subtraction angiography; VA, vertebral artery.
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Figure 3. The left VA was not showed on brain MRA. bilateral VA showed similar diameter in intracranial part to the VA union on MRI-BPAS, which indicated that there was dilation in the left VA intracranial portion. (A) Brain MRA image; (B, C) MRI-BPAS images. Abbreviations: BPAS, basi-parallel-anatomicalscanning; MRA, magnetic resonance angiography; MRI, magnetic resonance imaging; VA, vertebral artery.
increased in lower limbs. The modified Rankin Scale score was 2. On brain magnetic resonance angiography, the left VA did not show still (Fig 3, A). On MRI-BPAS (basi-parallel-anatomical-scanning [BPAS])2 bilateral VA showed similar diameter and left VA showed segmental dilation in intracranial penetrating part to the VA union (Fig 3, B,C).
Discussion In a series of 86 patients with MMI, Kim et al reported an incidence of 14% of patients with bilateral MMI.3 Most regions in the medulla oblongata are supplied by paired arteries, including the VA, posterior inferior cerebellar artery, anterior spinal artery (ASA), and posterior spinal artery, which may prevent bilateral infarctions. The paired ASAs usually originate from the paired VA, then merge into a single artery4 and show a ‘‘Y/V shape’’ (Fig 1). A systematic review (38 patients, from 1992 to 2011) reported that bilateral MMI was present with quadriplegia in 24% of patients, dysarthria in 18%, and hypoglossal palsy in 9%.5 Furthermore, approximately 9%-24% of patients with bilateral MMI may develop respiratory failure, which is more prevalent than that in unilateral MMI.5,6 Because the hypoglossal nucleus is typically located in the anteromedial territory near the border between the anteromedial and lateral territories in the dorsal portion of the medulla oblongata, the hypoglossal nucleus is seldom affected by anteromedial territory infarctions.7 This is supported by the presence of normal tongue movement in our case. Bilateral MMI with respiratory failure can be frequently misdiagnosed as Guillain-Barre syndrome, particularly when the initial symptoms develop as flaccid quadriplegia.8 In fact, the medical history is very important. Brain MRI and DWI are also helpful, as they can show the classical ‘‘heart’’ or ‘‘V/Y’’ appearance at the ventral medulla in patients with bilateral MMI.8,9 Of note, the abnormal MRI or DWI signal may be a small dot or linear shape at midline of the medulla in the early
stages of bilateral MMI.10 Guillain-Barre syndrome can also be confirmed by cerebrospinal findings of an elevated protein without pleocytosis at slightly later stages. According to previous magnetic resonance angiography findings, bilateral MMI might be related to artery stenosis or occlusion, including VA atherosclerosis (38.5%), VA occlusion (15.4%), basilar artery atherosclerosis (19.2%), dissection (7.7%), ASA occlusion (3.8%; an autopsy case), and no abnormalities (38.5%).5 Interestingly, in our case, brain DSA showed the right VA was more dominant than the left in extracranial portion, the left VA was occlusion at the distal intracranial portion (Fig 2). The anatomic variability of the left perforator branches that supply the bilateral anteromedial arterial or ASAs originating from the left VA might explain bilateral MMI with unilateral VA occlusion.11 Moreover, on latest MRI-BPAS, left VA showed segmental dilation in the intracranial portion, according to previous literature,2 another possibility might also exist; acute left VA and anterior spinal arteries occlusion could be caused by VA dissection.
Conclusion We highlight that ASAs could originate from a unilateral VA. Unilateral VA occlusion, no matter etiology, could cause MMI. Radiologists and neurologists should pay attention to the nondominant VA as bilateral MMI might be induced by dissection occlusion of nondominant VA that supply the bilateral anteromedial territories of the medulla.
References 1. Shono Y, Koga M, Toyoda K, et al. Medial medullary infarction identified by diffusion-weighted magnetic resonance imaging. Cerebrovasc Dis 2010;30:519-524. 2. Takada H, Hyogo T, Kataoka T, et al. Diagnosis of vertebral artery dissection by basi-parallel anatomical scanning (BPAS) MRI. Interv Neuroradiol 2006;12(Suppl 1):129-132. 3. Kim JS, Han YS. Medial medullary infarction: clinical, imaging, and outcome study in 86 consecutive patients. Stroke 2009;40:3221-3225.
e244 4. Kim K, Lee HS, Jung YH, et al. Mechanism of medullary infarction based on arterial territory involvement. J Clin Neurol 2012;8:116-122. 5. Pongmoragot J, Parthasarathy S, Selchen D, et al. Bilateral medial medullary infarction: a systematic review. J Stroke Cerebrovasc Dis 2013;22:775-780. 6. Kameda W, Kawanami T, Kurita K, et al. Lateral and medial medullary infarction: a comparative analysis of 214 patients. Stroke 2004;35:694-699. 7. Duvernoy HM. Human brain stem vessels. 2nd ed. New York: Springer 1999.
L. ZHANG ET AL. 8. Ma L, Deng Y, Wang J, et al. Bilateral medial medullary infarction presenting as Guillain-Barre-like syndrome. Clin Neurol Neurosurg 2011;113:589-591. 9. Parsi K, Itgampalli RK, Suryanarayana A, et al. Bilateral medial medullary infarction: heart appearance. Neurol India 2013;61:84-85. 10. Torabi AM. Bilateral medial medullary stroke: a challenge in early diagnosis. Case Rep Neurol Med 2013;2013:274373. 11. Gillilan LA. The correlation of the blood supply to the human brain stem with clinical brain stem lesions. J Neuropathol Exp Neurol 1964;23:78-108.
Bilateral Medial Medullary Infarction with Nondominant Vertebral Artery Occlusion Lei Zhang, MS,* Gui-lian Zhang, PhD,† Ju-mei Du, MSc,* and Zhu-lin Ma, MSc†
Bilateral medial medullary infarction (MMI) is a rare stroke subtype. Here, we report a case with bilateral MMI caused by nondominant vertebral artery occlusion confirmed by brain digital subtraction angiography and magnetic resonance imaging basi-parallel-anatomical-scanning. We highlight that anterior spinal arteries could originate from a unilateral vertebral artery (VA). Radiologists and neurologists should pay attention to the nondominant VA as bilateral MMI may be induced by occlusion of nondominant VA that supplies the bilateral anteromedial territories of the medulla. Key Words: Bilateral medial medullary infarction—nondominant vertebral artery—stroke—MRI-BPAS. Ó 2015 by National Stroke Association
Introduction Medial medullary infarction (MMI) is a rare stroke subtype, account for only .5%-1.5% of all strokes, whereas bilateral MMI is even rarer.1 Although there are some previous reports of bilateral MMI, bilateral MMI caused by nondominant vertebral artery (VA) occlusion confirmed by brain digital subtraction angiography (DSA) is very uncommon.
Case Report A 48-year-old man was taken to our hospital with weakness in 4 limbs and slurred speech that started From the *Department of Neurology, The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, Shaanxi Province; and †Department of Neurology, The Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xi’an, Shaanxi Province, China. Received October 24, 2014; revision received February 7, 2015; accepted April 3, 2015. Address correspondence to Gui-lian Zhang, PhD, Department of Neurology, The Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, No. 157 West 5 Road, Xi’an 710004, Shaanxi Province, China. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2015 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.04.005
5 hours prior. According to the patient’s family, the patient was at home when he felt mild weakness in his right upper limb and right lower limb, which progressively worsened into tetraplegia within a few minutes, with slurred speech, dysphagia, and irritating cough due to reflux of liquids. The patient had a history of hypertension and cigarette smoking. Neurologic examination revealed breathing difficulty, dysarthria, hyporeflexia, quadriplegia, and bilateral extensor plantar reflexes. The power in his 4 limbs was 0 of 5. The National Institutes of Health Stroke Scale score was 21. His routine laboratory tests including blood count, renal and hepatic function tests, erythrocyte sedimentation rate, C-reactive protein, and urinary tests were normal. Brain magnetic resonance imaging (MRI) showed a hyperintense ‘‘heart appearance’’ signal in the bilateral anteromedial medullae on axial T2-weighted imaging (Fig 1, A), whereas diffusion-weighted images (DWIs) revealed a corresponding area of restricted diffusion (Fig 1, B). The patient then underwent a brain DSA, which showed no abnormalities in the basilar artery or wholly right VA (Fig 2, A). However, the left VA exhibited wholly slenderer than the right VA in extracranial portion. The left VA showed the nondominant and occlusion in the distal intracranial part (Fig 2, B). The patient was diagnosed with acute bilateral MMI.
Journal of Stroke and Cerebrovascular Diseases, Vol. 24, No. 9 (September), 2015: pp e241-e244
e241
e242
L. ZHANG ET AL.
Figure 1. Brain MRI showed bilateral medial medullary infarction. (A) Axial T2WI image showed a ‘‘heart appearance’’ area of hyperintense signal in the bilateral anteromedial medullae. (B) Axial DWI image showed a ‘‘heart appearance’’ area of restricted diffusion in the medulla. Abbreviations: DWI, diffusion-weighted imaging; T2WI, T2-weighted imaging; MRI, magnetic resonance imaging.
On day 3 of admission, he received a tracheotomy mask because of respiratory distress. At 7 weeks after hospitalization, his slurred speech showed significant improvement. Further, the power was 4 of 5 in the left upper
limb and bilateral lower limb, and 3 of 5 in the right upper limb, the National Institutes of Health Stroke Scale score was 5. At 1 year after onset, his voice was hoarse. The power was almost normal in limbs, but muscle tone still
Figure 2. Brain DSA showed no abnormalities in the right VA and basilar artery, and the right VA was more dominant than the left in extracranial portion, the left VA was occluded at the distal intracranial portion. (A) Basilar artery and intracranial portion of right VA. (B) Extracranial portion of left VA. (C) Extracranial portion of right VA. (D) Extracranial portion of left VA. Abbreviations: DSA, digital subtraction angiography; VA, vertebral artery.
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Figure 3. The left VA was not showed on brain MRA. bilateral VA showed similar diameter in intracranial part to the VA union on MRI-BPAS, which indicated that there was dilation in the left VA intracranial portion. (A) Brain MRA image; (B, C) MRI-BPAS images. Abbreviations: BPAS, basi-parallel-anatomicalscanning; MRA, magnetic resonance angiography; MRI, magnetic resonance imaging; VA, vertebral artery.
increased in lower limbs. The modified Rankin Scale score was 2. On brain magnetic resonance angiography, the left VA did not show still (Fig 3, A). On MRI-BPAS (basi-parallel-anatomical-scanning [BPAS])2 bilateral VA showed similar diameter and left VA showed segmental dilation in intracranial penetrating part to the VA union (Fig 3, B,C).
Discussion In a series of 86 patients with MMI, Kim et al reported an incidence of 14% of patients with bilateral MMI.3 Most regions in the medulla oblongata are supplied by paired arteries, including the VA, posterior inferior cerebellar artery, anterior spinal artery (ASA), and posterior spinal artery, which may prevent bilateral infarctions. The paired ASAs usually originate from the paired VA, then merge into a single artery4 and show a ‘‘Y/V shape’’ (Fig 1). A systematic review (38 patients, from 1992 to 2011) reported that bilateral MMI was present with quadriplegia in 24% of patients, dysarthria in 18%, and hypoglossal palsy in 9%.5 Furthermore, approximately 9%-24% of patients with bilateral MMI may develop respiratory failure, which is more prevalent than that in unilateral MMI.5,6 Because the hypoglossal nucleus is typically located in the anteromedial territory near the border between the anteromedial and lateral territories in the dorsal portion of the medulla oblongata, the hypoglossal nucleus is seldom affected by anteromedial territory infarctions.7 This is supported by the presence of normal tongue movement in our case. Bilateral MMI with respiratory failure can be frequently misdiagnosed as Guillain-Barre syndrome, particularly when the initial symptoms develop as flaccid quadriplegia.8 In fact, the medical history is very important. Brain MRI and DWI are also helpful, as they can show the classical ‘‘heart’’ or ‘‘V/Y’’ appearance at the ventral medulla in patients with bilateral MMI.8,9 Of note, the abnormal MRI or DWI signal may be a small dot or linear shape at midline of the medulla in the early
stages of bilateral MMI.10 Guillain-Barre syndrome can also be confirmed by cerebrospinal findings of an elevated protein without pleocytosis at slightly later stages. According to previous magnetic resonance angiography findings, bilateral MMI might be related to artery stenosis or occlusion, including VA atherosclerosis (38.5%), VA occlusion (15.4%), basilar artery atherosclerosis (19.2%), dissection (7.7%), ASA occlusion (3.8%; an autopsy case), and no abnormalities (38.5%).5 Interestingly, in our case, brain DSA showed the right VA was more dominant than the left in extracranial portion, the left VA was occlusion at the distal intracranial portion (Fig 2). The anatomic variability of the left perforator branches that supply the bilateral anteromedial arterial or ASAs originating from the left VA might explain bilateral MMI with unilateral VA occlusion.11 Moreover, on latest MRI-BPAS, left VA showed segmental dilation in the intracranial portion, according to previous literature,2 another possibility might also exist; acute left VA and anterior spinal arteries occlusion could be caused by VA dissection.
Conclusion We highlight that ASAs could originate from a unilateral VA. Unilateral VA occlusion, no matter etiology, could cause MMI. Radiologists and neurologists should pay attention to the nondominant VA as bilateral MMI might be induced by dissection occlusion of nondominant VA that supply the bilateral anteromedial territories of the medulla.
References 1. Shono Y, Koga M, Toyoda K, et al. Medial medullary infarction identified by diffusion-weighted magnetic resonance imaging. Cerebrovasc Dis 2010;30:519-524. 2. Takada H, Hyogo T, Kataoka T, et al. Diagnosis of vertebral artery dissection by basi-parallel anatomical scanning (BPAS) MRI. Interv Neuroradiol 2006;12(Suppl 1):129-132. 3. Kim JS, Han YS. Medial medullary infarction: clinical, imaging, and outcome study in 86 consecutive patients. Stroke 2009;40:3221-3225.
e244 4. Kim K, Lee HS, Jung YH, et al. Mechanism of medullary infarction based on arterial territory involvement. J Clin Neurol 2012;8:116-122. 5. Pongmoragot J, Parthasarathy S, Selchen D, et al. Bilateral medial medullary infarction: a systematic review. J Stroke Cerebrovasc Dis 2013;22:775-780. 6. Kameda W, Kawanami T, Kurita K, et al. Lateral and medial medullary infarction: a comparative analysis of 214 patients. Stroke 2004;35:694-699. 7. Duvernoy HM. Human brain stem vessels. 2nd ed. New York: Springer 1999.
L. ZHANG ET AL. 8. Ma L, Deng Y, Wang J, et al. Bilateral medial medullary infarction presenting as Guillain-Barre-like syndrome. Clin Neurol Neurosurg 2011;113:589-591. 9. Parsi K, Itgampalli RK, Suryanarayana A, et al. Bilateral medial medullary infarction: heart appearance. Neurol India 2013;61:84-85. 10. Torabi AM. Bilateral medial medullary stroke: a challenge in early diagnosis. Case Rep Neurol Med 2013;2013:274373. 11. Gillilan LA. The correlation of the blood supply to the human brain stem with clinical brain stem lesions. J Neuropathol Exp Neurol 1964;23:78-108.
![[A case of bilateral medial medullary infarction caused by unilateral vertebral artery dissection].](/assets/img/hold.png)
