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Ulnar Nerve Palsy–like Motor and Sensory Loss Caused by a Small Cortical Infarct
Case Report
Ulnar Nerve Palsy–like Motor and Sensory Loss Caused by a Small Cortical Infarct Tatsuya Ueno, MD,*‡ Masahiko Tomiyama, MD,*†‡ Rie Haga, MD,* Haruo Nishijima, MD,*‡ Tomoya Kon, MD,* Yukihisa Funamizu, MD,* Yasuo Miki, MD,* Akira Arai, MD,* Chieko Suzuki, MD,* and Masayuki Baba, MD*
A 56-year-old man with a small infarct in the left precentral knob area induced both motor and sensory impairments that were similar to right ulnar nerve palsy. The only difference from ulnar nerve palsy was that the patient showed sensory disturbance not only on the ulnar side but also on the radial side of the right ring finger. Key Words: Cortical infarction—precentral knob—ulnar nerve palsy. Ó 2012 by National Stroke Association
A 56-year-old right-handed man was hospitalized because of left ataxic hemiparesis caused by branch atheromatous disease in the right putamen and corona radiata. He had been hypertensive for a few years without treatment. During hospitalization, he noticed difficulty in fine movements of the right hand at the time of awakening. Neurologic examinations revealed no disturbance of consciousness or mental status. Cranial nerves were normal. A manual muscle test revealed mild weakness of the right palmar and dorsal interosseous muscles, right abductor digiti minimi, right flexor digitorum profundus, and right flexor digiti minimi. Grasping power was 20 kg on the right and 27 kg on the left side. Muscle strength was normal in abduction and adduction of the shoulder, flexion and extension of the elbow, flexor and extension of the From the *Department of Neurology, †Stroke Unit, Aomori Prefectural Central Hospital, Aomori; and ‡Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. Received December 22, 2010; revision received February 9, 2011; accepted February 14, 2011. Address correspondence to Tatsuya Ueno, MD, Department of Neurology, Aomori Prefectural Central Hospital, 2-1-1 Higashitsukurimichi, Aomori 030-8553, Japan. E-mail: tatsuya_ueno@med. pref.aomori.jp. 1052-3057/$ - see front matter Ó 2012 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2011.02.008
wrist, and extension of fingers. Weakness was not seen in lower limbs. In addition, hypesthesia in pinprick and light touch tests were found in the right ring and little fingers. However, differences in sense were not observed between the ulnar and radial side of the right ring finger. The joint position sense and vibration sense were normal. Tendon reflexes were preserved and the plantar responses were flexor. A nerve conduction study revealed no abnormalities in the right median and ulnar nerves. Diffusionweighted imaging of a magnetic resonance imaging (MRI) scan revealed a high-intensity area between the precentral knob and subcortical white matter of the left frontal cortex (Fig 1). No abnormality was seen in magnetic resonance angiography. MRI of the cervical spine was normal. The results of laboratory examinations were unremarkable. Electrocardiographic and carotid ultrasound studies were normal. Transthoracic echocardiography revealed an expansion of the left atrium and left ventricular hypertrophy. The left ventricular wall motion was hypokinetic in the anteroseptal wall. Transesophageal echocardiography revealed plaques on the aortic arch and descending aorta. However, no certain embolic source was found.
Discussion A small cortical infarct of the precentral knob causes weakness similar to ulnar nerve palsy,1,2 often called
Journal of Stroke and Cerebrovascular Diseases, Vol. 21, No. 8 (November), 2012: pp 903.e3-903.e4
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Figure 1. Upper panel, T1-weighted magnetic resonance imaging scan. Lower panel, Diffusion-weighted imaging of the magnetic resonance imaging scan. Arrowhead indicates the precentral knob. Pictures in the lower panel reveal a small high-intensity area from the medial side of the precentral knob to the subcortical white matter below the precentral knob.
pseudoulnar palsy.3 A posterior wall lesion of the central sulcus results in sensory impairment on the ulnar side of the hand.4,5 However, our patient had not only weakness like right ulnar nerve palsy but also hypesthesia in both right ring and little fingers. The patient appeared to have right ulnar nerve palsy. There has been a reported case presenting with motor and sensory loss like ulnar nerve palsy3; however, that patient had two distinct small infarcts in the precentral knob and posterior wall of the central sulcus.3 Our patient is the first case in which an isolated cerebral infarct brought about motor and sensory loss mimicking ulnar nerve palsy. Deep sensation was preserved in our patient. Primary somatosensory area 3a receives kinesthetic afferents rather than cutaneous inputs, while areas 3b and 1 receive more superficial stimuli.6 The infarct of subcortical white matter might affect projection fibers to areas 3b and 1, not area 3a. The lesion in the precentral knob (Fig 1) caused weakness similar to ulnar nerve palsy and the expansion of the infarct to the subcortical white matter (Fig 1) might involve fibers to the posterior wall of the central sulcus and then
caused sensory loss in the ring and little fingers. Motor and sensory loss like ulnar nerve palsy may result from a small infarct in the precentral knob area.
References 1. Kim JS. Predominant involvement of a particular group of fingers due to small, cortical infarction. Neurology 2001; 56:1677-1682. 2. Gass A, Szabo K, Behrens S, et al. A diffusion-weighted MRI study of acute ischemic distal arm paresis. Neurology 2001;57:1589-1594. 3. Phan TG, Evans BA, Huston J. Pseudoulnar palsy from a small infarct of the precentral knob. Neurology 2000; 54:2185. 4. Takahashi N, Kawamura M, Araki S. Isolated hand palsy due to cortical infarction: Localization of the motor hand area. Neurology 2002;58:1412-1414. 5. Cerrato P, Lentini A, Baima C, et al. Pseudo-ulnar sensory loss in a patient from a small cortical infarct of the postcentral knob. Neurology 2005;64:1981-1982. 6. Mountcastle VB. Perceptual neuroscience: The cerebral cortex. Cambridge, MA: Harvard University Press, 1998.
Ulnar Nerve Palsy–like Motor and Sensory Loss Caused by a Small Cortical Infarct Tatsuya Ueno, MD,*‡ Masahiko Tomiyama, MD,*†‡ Rie Haga, MD,* Haruo Nishijima, MD,*‡ Tomoya Kon, MD,* Yukihisa Funamizu, MD,* Yasuo Miki, MD,* Akira Arai, MD,* Chieko Suzuki, MD,* and Masayuki Baba, MD*
A 56-year-old man with a small infarct in the left precentral knob area induced both motor and sensory impairments that were similar to right ulnar nerve palsy. The only difference from ulnar nerve palsy was that the patient showed sensory disturbance not only on the ulnar side but also on the radial side of the right ring finger. Key Words: Cortical infarction—precentral knob—ulnar nerve palsy. Ó 2012 by National Stroke Association
A 56-year-old right-handed man was hospitalized because of left ataxic hemiparesis caused by branch atheromatous disease in the right putamen and corona radiata. He had been hypertensive for a few years without treatment. During hospitalization, he noticed difficulty in fine movements of the right hand at the time of awakening. Neurologic examinations revealed no disturbance of consciousness or mental status. Cranial nerves were normal. A manual muscle test revealed mild weakness of the right palmar and dorsal interosseous muscles, right abductor digiti minimi, right flexor digitorum profundus, and right flexor digiti minimi. Grasping power was 20 kg on the right and 27 kg on the left side. Muscle strength was normal in abduction and adduction of the shoulder, flexion and extension of the elbow, flexor and extension of the From the *Department of Neurology, †Stroke Unit, Aomori Prefectural Central Hospital, Aomori; and ‡Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. Received December 22, 2010; revision received February 9, 2011; accepted February 14, 2011. Address correspondence to Tatsuya Ueno, MD, Department of Neurology, Aomori Prefectural Central Hospital, 2-1-1 Higashitsukurimichi, Aomori 030-8553, Japan. E-mail: tatsuya_ueno@med. pref.aomori.jp. 1052-3057/$ - see front matter Ó 2012 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2011.02.008
wrist, and extension of fingers. Weakness was not seen in lower limbs. In addition, hypesthesia in pinprick and light touch tests were found in the right ring and little fingers. However, differences in sense were not observed between the ulnar and radial side of the right ring finger. The joint position sense and vibration sense were normal. Tendon reflexes were preserved and the plantar responses were flexor. A nerve conduction study revealed no abnormalities in the right median and ulnar nerves. Diffusionweighted imaging of a magnetic resonance imaging (MRI) scan revealed a high-intensity area between the precentral knob and subcortical white matter of the left frontal cortex (Fig 1). No abnormality was seen in magnetic resonance angiography. MRI of the cervical spine was normal. The results of laboratory examinations were unremarkable. Electrocardiographic and carotid ultrasound studies were normal. Transthoracic echocardiography revealed an expansion of the left atrium and left ventricular hypertrophy. The left ventricular wall motion was hypokinetic in the anteroseptal wall. Transesophageal echocardiography revealed plaques on the aortic arch and descending aorta. However, no certain embolic source was found.
Discussion A small cortical infarct of the precentral knob causes weakness similar to ulnar nerve palsy,1,2 often called
Journal of Stroke and Cerebrovascular Diseases, Vol. 21, No. 8 (November), 2012: pp 903.e3-903.e4
903.e3
T. UENO ET AL.
903.e4
Figure 1. Upper panel, T1-weighted magnetic resonance imaging scan. Lower panel, Diffusion-weighted imaging of the magnetic resonance imaging scan. Arrowhead indicates the precentral knob. Pictures in the lower panel reveal a small high-intensity area from the medial side of the precentral knob to the subcortical white matter below the precentral knob.
pseudoulnar palsy.3 A posterior wall lesion of the central sulcus results in sensory impairment on the ulnar side of the hand.4,5 However, our patient had not only weakness like right ulnar nerve palsy but also hypesthesia in both right ring and little fingers. The patient appeared to have right ulnar nerve palsy. There has been a reported case presenting with motor and sensory loss like ulnar nerve palsy3; however, that patient had two distinct small infarcts in the precentral knob and posterior wall of the central sulcus.3 Our patient is the first case in which an isolated cerebral infarct brought about motor and sensory loss mimicking ulnar nerve palsy. Deep sensation was preserved in our patient. Primary somatosensory area 3a receives kinesthetic afferents rather than cutaneous inputs, while areas 3b and 1 receive more superficial stimuli.6 The infarct of subcortical white matter might affect projection fibers to areas 3b and 1, not area 3a. The lesion in the precentral knob (Fig 1) caused weakness similar to ulnar nerve palsy and the expansion of the infarct to the subcortical white matter (Fig 1) might involve fibers to the posterior wall of the central sulcus and then
caused sensory loss in the ring and little fingers. Motor and sensory loss like ulnar nerve palsy may result from a small infarct in the precentral knob area.
References 1. Kim JS. Predominant involvement of a particular group of fingers due to small, cortical infarction. Neurology 2001; 56:1677-1682. 2. Gass A, Szabo K, Behrens S, et al. A diffusion-weighted MRI study of acute ischemic distal arm paresis. Neurology 2001;57:1589-1594. 3. Phan TG, Evans BA, Huston J. Pseudoulnar palsy from a small infarct of the precentral knob. Neurology 2000; 54:2185. 4. Takahashi N, Kawamura M, Araki S. Isolated hand palsy due to cortical infarction: Localization of the motor hand area. Neurology 2002;58:1412-1414. 5. Cerrato P, Lentini A, Baima C, et al. Pseudo-ulnar sensory loss in a patient from a small cortical infarct of the postcentral knob. Neurology 2005;64:1981-1982. 6. Mountcastle VB. Perceptual neuroscience: The cerebral cortex. Cambridge, MA: Harvard University Press, 1998.