A 58-year-old man from Delhi presents to the emergency department with acute onset of vertigo, nystagmus, and ipsilateral facial numbness. On examination, he has ipsilateral loss of pain and temperature sensation over the face, contralateral loss of pain and temperature sensation over the body, and ipsilateral Horner syndrome. MRI brain shows an acute infarct in the lateral medulla. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis: Wallenberg Syndrome (Lateral Medullary Syndrome) ### Anatomical Basis The clinical triad of ipsilateral facial sensory loss, contralateral body sensory loss, and ipsilateral Horner syndrome localizes the lesion to the **lateral medulla**. This syndrome results from occlusion of the **posterior inferior cerebellar artery (PICA)** or the **vertebral artery**. ### Pathophysiology The lateral medullary infarct damages: 1. **Spinal trigeminal nucleus and tract** → ipsilateral facial pain/temperature loss 2. **Spinothalamic tract** → contralateral body pain/temperature loss 3. **Oculomotor sympathetic fibers** → ipsilateral Horner syndrome (miosis, ptosis, anhidrosis) 4. **Inferior cerebellar peduncle** → ipsilateral ataxia ### Management Algorithm ```mermaid flowchart TD A[Acute ischemic stroke suspected]:::outcome --> B{Time from onset?}:::decision B -->|< 4.5 hours| C[IV thrombolysis eligible?]:::decision B -->|4.5-24 hours| D[Check for wake-up stroke/extended window criteria]:::decision C -->|Yes, no contraindications| E[Administer IV alteplase]:::action C -->|No| F[Consider mechanical thrombectomy if large vessel occlusion]:::action D -->|Meets criteria| G[Consider thrombectomy]:::action D -->|Does not meet| H[Supportive care + secondary prevention]:::action E --> I[Monitor for reperfusion and complications]:::outcome ``` **Key Point:** Wallenberg syndrome is an acute ischemic stroke. Time-dependent thrombolytic therapy (IV alteplase within 4.5 hours) is the standard of care and offers the best chance of salvaging ischemic penumbra. **High-Yield:** The classic teaching is that Wallenberg syndrome presents with: - **Ipsilateral:** facial sensory loss, Horner syndrome, ataxia, vocal cord paralysis - **Contralateral:** body pain/temperature loss **Clinical Pearl:** Lateral medullary infarcts typically have a favorable prognosis compared to other brainstem strokes because they spare the corticospinal tract (which runs medially), preserving motor function. **Warning:** ~~Decompressive craniectomy~~ is NOT indicated for lateral medullary infarcts; it is reserved for malignant cerebellar infarcts with mass effect or large hemispheric infarcts with cerebral edema. ### Why IV Thrombolysis Is Correct - Patient is within the 4.5-hour thrombolytic window (acute presentation) - No absolute contraindications mentioned (no hemorrhage on imaging, no recent surgery) - Restores blood flow to the ischemic territory - Evidence-based guideline recommendation for acute ischemic stroke [cite:Harrison 21e Ch 297]