tutorial questions

Question 1

A 25 year-old man fell from scaffolding and fractured his spine in the mid-thoracic region. When examined he had no movement in the right leg and proprioception and sensation for fine discriminative touch was impaired below T10 on the right.
However, he could feel pain and changes in temperature in his right leg. In contrast his left leg moved normally, had normal touch sensation but retained no sensation for pain or temperature.
What is the site and extent of the lesion?
Explain the pattern of symptoms in neuroanatomical terms.
Is he likely to recover the lost movement and sensation?

Answer 1

• Site is T10 – mid thoracic hemisection of spinal cord on R hand side – Brown Sequard syndrome
• Pattern of symptoms – ipsilateral of proprioception – dorsal column and contralateral of pain – spinothalamic and ipsilateral loss of movement – corticospinal
• Spinothalamic decussate in the spinal cord this is why it is contralateral
• Likely to recover – no – because neurons in the CNS are less likely to regenerate. It depends on how much the tracts have been affected, if there is only partial impediment there might be a small chance that regeneration can take place
• Treatment – rehab/physio/stem cell therapy – pluripotent stem cells grown in vitro – differentiate into any cell you want them to

Question 2

A 75 year-old patient had a stroke, the immediate signs of which were moderate weakness and loss of sensation in the left hand and forearm. During the following weeks the weakness and sensory disturbance resolved, but periodically he had strange sensations in his left hand, such as sudden coldness or feeling of increased pressure. Occasionally the feeling spread up his arm and sometimes these episodes were accompanied by jerking movements of the arm, which he could not control.
What was the location of the infarct that led to the initial stroke symptoms?
What are the strange sensations and jerking movements a sign of?
What treatment could be given to reduce or prevent these involuntary movements?
What is likely to happen if the condition is left untreated?

Answer 2

• Middle cerebral artery. R parietal cortex – close or in primary somatosensory cortex
• Why would you have jerking movements – tissue damage from stroke cause epilepsy - myoclonus because neurons dying in somatosensory cortex this sends discharge signals to motor cortex
• Treatment – GABA agonist – anticonvulsant to treat seizures which reduces Na and so signals
• Untreated – seizure spread to whole primary motor cortex and can spread to next hemisphere and cause more generalised seizures

Question 3

Over a period of several days a 55 year-old man developed total paralysis of his body and most of his face. He could not swallow or speak. Horizontal eye movements were impaired but vertical eye movements and eye blinks were maintained.
Communication via a code of eye movements showed that he remained mentally alert and that sensation over his whole body remained intact. A brainstem vascular lesion was suspected.
Which pathway has been affected?
Why are vertical but not horizontal eye movements maintained?
Where in the brainstem is the lesion?
Why are sensation and consciousness not affected?
Which artery is most likely to have been involved?

Answer 3

Which pathway affected – corticospinal anterior and lateral, and corticobulbar (projects to brainstem)
Horizontal eye movements lost because of damage to the abducens nerve. The trochlear nerve is not affected and so the vertical eye movement is fine. Eye blinking is ok so the oculomotor is fine. Paralysis of face – meaning that the facial nerve is affected. Problem swallowing so glossopharyngeal. Problem speech - vagus
Where in the brainstem basal part of upper pons – anterior the pons – this is where the emergence of the CN
Why are sensation and consciousness not affected – because the dorsal roots are posterior so sensation wouldn’t be affected. Similar for arousal because the reticular formation is more posterior
What artery supplies – superior part of the basilar artery – thrombus of the basilar artery giving pt locked in syndrome – can move eyes but paralysed. pons cant get any more blood supply because it is not part of the circle of willis – there is no other means for it to get blood. Pontine arteries not extensive enough because pons is so big and there are so many CNs