EMQs in Clinical Medicine.pdf - Peshawar Medical College

100 Neurology
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B
There should be no loss of consciousness in drop attacks. The cause is
unclear and they usually resolve spontaneously.
A 21-year-old student presents with hyperventilation, tachycardia
and light-headedness and is brought to A&E after ‘blacking out’.
Hyperventilation leads to a reduction in the PaCO 2 and a respiratory alkalosis.
Hypocapnic induced cerebral vessel vasoconstriction gives rise to
the light-headedness and ‘blacking out’.
Hyperventilation may be an appropriate response to a metabolic acidosis
or as a response to primary CNS pathology affecting the brain stem.
Hyperventilation can also occur as a means to increase PaO 2 in a patient
with asthma, chronic obstructive pulmonary disease (COPD), etc.
In this case hyperventilation has been provoked by anxiety and is characteristically
associated with symptoms of lightheadedness, and circumoral
and distal paraesthesia.
When a patient presents with a symptom of ‘blacking out’, it is important
to find out exactly what he or she means by that term, i.e. loss of vision
or loss of consciousness.
A 34-year-old woman falls to the ground after hearing some
bad news.
Vasovagal syncope results from reflex bradycardia and peripheral
vasodilatation in response to pain, emotion or prolonged standing. The
patient may later report symptoms of nausea and closing in of the visual
fields before collapse. The patient is unconscious for around 2 min and
recovery is rapid in the supine position.
A 60-year-old woman who has recently started antihypertensive
medication has a fall after getting out of bed.
Antihypertensive medication is a common cause of postural hypotension
particularly in elderly people. This may occur as a result of hypovolaemia
and/or autonomic dysfunction, e.g. diuretics may cause hypovolaemia
and blockers affect the autonomic nervous system. Other
drug causes of autonomic dysfunction include L-dopa and tricyclic antidepressants.
38 Site of neurological lesion
Answers: L H J C E
L
A 75-year-old, right-handed woman is noted to ignore stimuli on the
left side of her body.
This patient has sensory neglect suggesting a non-dominant hemisphere
lesion. As the patient is right handed, we know that the dominant lobe
must be on the left side, and hence the pathology is in the right
parietal lobe.