50 year old female patient presented with R/S hemiplegia, L/S horners xn, neck pain. Most likely diagnosis A. L/S internal capsular infraction B. Lateral medullary Xn C. Pancoat’s tumour D. Vertebral artery dissection E. Carotid artery dissection
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I now have all the information needed. Here is the detailed answer:
Answer: D. Vertebral Artery Dissection
The Diagnostic Triad
| Finding | Side | Localizing value |
|---|---|---|
| Hemiplegia | Right (contralateral) | Left corticospinal tract |
| Horner's syndrome | Left (ipsilateral) | Left descending oculosympathetic pathway |
| Neck pain | Present | Vascular/cervical pathology |
This is the classic triad of left vertebral artery dissection causing ischemia in the lateral medulla / brainstem territory.
Why Vertebral Artery Dissection?
The key insight is the crossed pattern: ipsilateral Horner's + contralateral hemiplegia + neck pain in a relatively young/middle-aged patient.
When a vertebral artery dissects in its cervical or intracranial course, two things happen simultaneously:
-
Ipsilateral Horner's syndrome - the dissecting hematoma compresses or damages the pericarotid/perivertebral sympathetic plexus (descending oculosympathetic fibers run alongside the vertebral and carotid arteries)
-
Contralateral hemiplegia - distal ischemia/embolism from the dissection affects the brainstem (medulla/pons), where corticospinal fibers have not yet crossed, or causes cortical ischemia after crossing - resulting in contralateral motor deficit
-
Neck pain - the intramural hemorrhage in the vessel wall is painful; posterior neck pain is a hallmark of vertebral artery dissection
From Rosen's Emergency Medicine (Clinical Features section):
"The classic presentation is that of a relatively young person with severe, unilateral posterior headache and a rapidly progressive neurologic deficit with symptoms of brainstem and cerebellar ischemia. Common findings include vertigo, severe vomiting, ataxia, diplopia, hemiparesis, unilateral facial weakness, and tinnitus."
From Localization in Clinical Neurology, 8e:
"Atherosclerotic steno-occlusive disease or dissection of the intracranial vertebral artery can lead to a total unilateral hemimedullary (Babinski-Nageotte) syndrome... characterized by contralateral hemiplegia [combined with ipsilateral Horner's]."
Why Not the Other Options?
A. Left internal capsular infarction - An internal capsule stroke causes contralateral (right) hemiplegia, but does NOT produce Horner's syndrome. The sympathetic pathway does not pass through the internal capsule. Also, no neck pain.
B. Lateral medullary syndrome (Wallenberg) - This is close, but Wallenberg syndrome classically does NOT cause hemiplegia. The corticospinal tract is in the medial medulla, not the lateral medulla. Wallenberg gives ipsilateral Horner's + contralateral pain/temperature loss on the body + ipsilateral facial numbness + ataxia - but spares the motor tracts. Hemiplegia is notably ABSENT in pure Wallenberg. (Note: Wallenberg can result FROM a vertebral artery dissection, making D the more upstream/complete answer.)
C. Pancoast's tumour - A superior sulcus lung tumour can cause ipsilateral Horner's (T1 sympathetic chain) and arm/hand weakness from brachial plexus invasion, but does NOT cause contralateral hemiplegia or neck pain in this pattern. It would cause ipsilateral arm pain, not a crossed neurological deficit.
E. Carotid artery dissection - This is a good differential. Carotid dissection gives: ipsilateral Horner's + contralateral hemispheric deficits (hemiplegia is possible) + neck/face pain. However, the neck pain in carotid dissection is typically anterior neck pain often radiating to the jaw/eye, while vertebral artery dissection classically causes posterior neck pain. More importantly, carotid dissection does not typically produce brainstem signs, while the combination here with prominent neck pain in a middle-aged woman fits vertebral dissection better in the exam context. Also, vertebral dissection more classically produces this exact crossed brainstem picture.
Key Teaching Point
The combination of:
- Ipsilateral Horner's + contralateral hemiplegia + neck pain
- In a patient under 60 (cervical artery dissection is the #1 cause of stroke in patients under 50, accounting for 10-25% of cases in this age group)
...is the textbook presentation of vertebral artery dissection.
Imaging of choice: MRI/MRA of head and neck (sensitivity ~95%) or CT angiography. Look for the "crescent sign" - a hyperintense intramural hematoma on T1-fat-sat sequences.
- Rosen's Emergency Medicine, Ch. 89 (Carotid and Vertebral Artery Dissection)
- Localization in Clinical Neurology, 8e (Vertebrobasilar Artery Syndromes)
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