Case 2

CASE 2 Girl with Sudden Weakness

• At the age of 6 years, a 10 year old girl had the sudden onset of a headache over the left frontal area followed by the acute onset of right sided weakness and inability to talk. She couldn’t move her right arm or leg. She could recognize her family and could understand what was said to her but she couldn’t talk. • Over the next few months, her strength improved so that she could walk but she still had problems using her right hand. She started to talk in one word sentences, then short phrases, and finally in full sentences. She would still have problems at times finding the right word to say or coming up with the correct name of an object.

Select the parts of the neurological examination that you need to see for localization of the patient's lesion. • • • • • •

Mental Status Exam Cranial Nerve Exam Coordination Exam Sensory Exam Motor Exam Gait exam

Mental Status Exam • The patient has occasional difficulty finding the words she wants to use and naming objects. • The rest of the mental status examination is normal.

Language • At the age of 6 years, this 10 year old girl had the sudden onset of a headache over the left frontal area followed by the acute onset of right sided weakness and inability to talk. She couldn’t move her right arm or leg. She could recognize her family and could understand what was said to her but she couldn’t talk. • Over the next few months, her strength improved so that she could walk but she still had problems using her right hand. She started to talk in one word sentences, then short phrases, and finally in full sentences. She would still have problems at times finding the right word to say or coming up with the correct name of an object

Motor examination • • • •

Right facial nerve Right upper extremity incoordination Right lower extremity incoordination Right side of body weakness and tone change • Right side of body hyperreflexia • Right side Babinski

RIGHT CRANIAL NERVE 7 DEFICIT – Upper Motor Neuron

"Y" Neuroaxis To localize the level of the lesion for this case, start with the "Y" neuroaxis. On the diagram, click the level(s) you think is involved.

Supratentorial "X" Neuroaxis Continue to localize the lesion for this case. On the diagram, click the side you think is involved.

Identify the damaged structure • SUPRATENTORIAL • > CORTEX • > LEFT SIDE:

Identify the damaged structure • Now that you have localized the level and the side of the lesion, identify the specific structures that are damaged. Use the VIEWING OPTIONS to review various structures

1 Genu of the corpus callosum 2 Splenium of the corpus callosum 3 Caudate 4Internal capsule 5 Putamen 6 Globus pallidus 7 Thalamus 8 Optic Radiation 9 Frontal cortex 10 Temporal cortex 11 Parietal cortex 12 Occipital cortex

CASE DISCUSSION • The patient had the acute onset of right sided weakness and inability to speak. The temporal profile of her illness is most consistent with a vascular event or a stroke. • On examination she has right sided weakness with the greatest deficit being in the hand. • She has mild asymmetry of the nasal labial folds with the right side being less distinct than the left. • There is no asymmetry to the action of the orbicularis oculi or frontalis muscles so this is most consistent with an upper motor neuron lesion affecting the lower half of the face (a “central” 7th nerve lesion). • The distribution of the extremity weakness, hypertonia, hyperreflexia, pathological reflexes, and gait are consistent with a right hemiparesis caused by an upper motor lesion. • Because the face as well as the extremities is involved, then the lesion has to be above the level of the 7th cranial nerve and it is on the left side of the brain.

We now need to consider her other findings to further help us localize the level of the lesion. • The patient had problems with expressive language. She could understand what was said to her but she couldn’t say anything. With time she regained her ability to talk but still has mild difficulty with finding the right word or naming objects. Her findings are consistent with an expressive aphasia which localizes to the posterior inferior frontal gyrus (Broca’s area) of the dominant hemisphere which for her is the left hemisphere.

So taking into account her right hemiparesis plus her expressive aphasia the lesion has to be at the supratentorial level in the left cerebral hemisphere • It has to involve the inferior frontal lobe as well as either the precentral gyrus or the white matter tracts coming from the motor cortex. The precentral gyrus or motor strip runs all the way from the Sylvian fissure to the central fissure and is supplied by both the middle cerebral and the anterior cerebral arteries (the middle cerebral artery for the face and upper extremity and the anterior cerebral artery for the trunk and lower extremity). So if we postulate that the motor deficit is from a lesion of the precentral gyrus then the vascular event that caused the stroke would have to be an occlusion of the internal carotid artery prior to the bifurcation into the anterior and middle cerebral arteries. That would be a huge infarct.

Another possible explanation for the hemiparesis • Lesion at the level of the internal capsule where the descending corticospinal and corticobulbar tracts are anatomically in a small area and supplied by branches of the middle cerebral artery. The best fit for a lesion would be the internal capsule and part of the frontal lobe which includes Broca’s area and part of the precentral gyrus.

POSSIBLE DAMAGED STRUCTURES

How do we explain the patient’s incoordination on the right side? The incoordination is not from a cerebellar lesion but rather from her corticospinal tract lesion

• CST lesion can cause incoordination

• The key distinguishing feature here is UMN signs

MRI image of the patient

• The patient’s MRI scan showed an infarction in this area. There was also infarction of the caudate and the putamen/gobus pallidus on the left as well. She didn’t have basal ganglia symptoms because with the hemiparesis the extrapyramidal dysfunction was not expressed.