This Week’s EMCQs – Week 1

QUESTION 1

A 67-year-old patient is brought in to Emergency after recurrent syncope. During her assessment, she becomes clammy and pale.

Her vital signs during this episode are:

BP        80/60

HR       40

GCS      13/15

Her ECG on arrival to ED before this episode is attached below…

ECG 1-1

Which one of the following is the most likely diagnosis of this patient?

A: Mobitz type I heart block

B: Mobitz type II heart block

C: Sick sinus syndrome

D: Sinus rhythm with prolonged pauses.

A: Mobitz type I heart block

B: Mobitz type II heart block

C: Sick sinus syndrome (Correct Answer)

D: Sinus rhythm with prolonged pauses.

Commentary

Intermittent ‘dropping’ of the P wave followed by escape rhythms in this ECG is a feature of sick sinus syndrome

Reference: Textbook of Adult Emergency Medicine, Cameron P et al, 4th edition. Page 233.

QUESTION 2

A 55-year-old man is involved in a minor motor vehicle accident at low speed and describes a ‘whiplash injury’. He self-extricated and went home to have a shower before presenting to ED. He presents with vertigo and nausea.

Examination reveals a constricted right pupil and a partial ptosis of the right eyelid.

He has a background history of diabetes, hypertension and ischemic heart disease.

Which of the following is the best option?

A: Dissociated sensory loss on the left trunk is common in this scenario

B: Left limb ataxia is likely

C: An MRI brain will identify the main pathology

D: A non-contrast CT Brain and C spine is the best modality to identify the main pathology

A: Dissociated sensory loss on the left trunk is common in this scenario (Correct answer)

B: Left limb ataxia is likely

C: An MRI brain will identify the main pathology

D: A non-contrast CT Brain and C spine is the best modality to identify the main pathology

Commentary

The patient has trauma related right vertebral dissection with posterior inferior cerebellar artery infarction and lateral medullary / Wallenberg syndrome.

Wallenberg syndrome (AKA lateral medullary infarction) presents with acute onset of vertigo and disequilibrium due to infarction of the ipsilateral posterior inferior cerebellar artery (or obstruction of the vertebral artery from which it arises).

Vertigo is the main feature, but abnormal eye movements, an ipsilateral Horner syndrome, ipsilateral limb ataxia, and a dissociated sensory loss (loss of pain and temperature sensation on the ipsilateral face and contralateral trunk with preserved vibration and position sense) can also occur. Hoarseness and dysphagia are additional features.

Can also occur due to traumatic vertebral artery dissection. The diagnosis of medullary infarction is established definitively with MRI. MRA is useful to assess for dissection.

Reference: UpToDate – Posterior circulation cerebrovascular syndromes.