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Discussion Starter · #1 ·
A 37-year-old pregnant woman is brought to the Emergency Department after being found unconscious. Her airway and circulation are stabilized. On examination, she is found to be completely paralyzed without response to voice or pain. When her eyelids are propped opened, she can respond to questions by moving her eyes upward for "yes" and downward for "no." She is unable to move her eyes laterally. A CT angiography study of her head and neck reveals a large occlusive thrombus. Which of the following locations of the thrombus would best account for this woman's presentation?
A. Basilar artery
B. Internal carotid artery
C. Middle cerebral artery
D. Posterior cerebral artery
E. Superior cerebellar artery
 

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I choose B

I'd say the Internal carotid artery. because the extraocular muscles are still functioning which means that the brain stem is still OK but all her other muscles are paralyzed by a complete block of arterial supply to the entire cortex so the culprit should be the internal carotid.

Am I right! :eek:
 

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no its basilar artery, abducent nerve axons leave brainstem from medial pons which is supplied by basilar artery

also corticospinal tracts are in the medial pons (locked-in syndrome)
 

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I agree with you

no its basilar artery, abducent nerve axons leave brainstem from medial pons which is supplied by basilar artery

also corticospinal tracts are in the medial pons (locked-in syndrome)
I agree with you ;)

Here's what emedicine said about it:

Basilar Artery Thrombosis Examination Findings:
The signs described can be present in different combinations. The recognized syndromes more commonly associated with basilar artery occlusion are:
  • Locked-in syndrome: It is caused by infarction of the basis pontis secondary to occlusive disease of the proximal and middle segments of the basilar artery, which leads to quadriplegia. Because the tegmentum of the pons is spared, the patient has a spared level of consciousness, preserved vertical eye movements, and blinking. Coma associated with oculomotor abnormalities and quadriplegia also indicates proximal basilar and midbasilar occlusive disease with pontine ischemia.
  • Top-of-the-basilar syndrome: This is the manifestation of upper brainstem and diencephalic ischemia caused by occlusion of the rostral basilar artery, usually by an embolus. Patients present with changes in the level of consciousness. They may experience visual symptoms such as hallucinations and/or blindness. Third nerve palsy and pupillary abnormalities are also frequent. Motor abnormalities include abnormal movements or posturing.
 

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i too will go with A. cos of the inability to move the eyes laterally. i.e effect on the abducens nerve whose nucleus is in the pons of the brainstem...
 

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Discussion Starter · #7 ·
The correct answer

The correct answer is A. This patient presents with a phenomenon known as "locked-in" syndrome. Unlike a persistent vegetative state, which is characterized by a loss of awareness and cognitive function, patients with locked-in syndrome are completely awake and cognitively intact with no abnormality of consciousness. However, they are unable to move the extremities and most of the face, and are often limited to communication by vertical eye movements or blinks. The disease results most commonly from large lesions in the brain stem, particularly at the base of the Pons, such as those produced by a thrombotic stroke to the basilar artery.
Occlusion of an internal carotid artery (choice B) is unlikely to present in the manner described because collateral circulation from the other internal carotid artery should compensate for the unilaterally reduced perfusion.
Middle cerebral artery strokes (choice C) usually present with lateralizing symptoms, such as a gaze deviation or hemiparesis. Since the parietal cortex is primarily perfused by this artery, symptoms involving parietal lobe dysfunction such as agnosias, apraxias, hemi-neglect, and language and calculation problems are more likely to occur.
The posterior cerebral artery (choice D) supplies the occipital lobe as well as the medial portions of the parietal and temporal cortex. Symptoms will usually be lateralizing, and visual changes are almost certainly present.
Occlusion of the superior cerebellar artery (choice E) would more likely present with ataxia and dysarthria than with the severe symptoms described in this patient.
A lesion of the ventral pons can result in "locked-in" syndrome, in which the patient develops quadriplegia and inability to speak but is aware, is awake, and can communicate by vertical eye movements or blinks. Branches of the basilar artery supply the ventral pons
 
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