A 38-year-old woman presents with sudden onset of right-sided facial drooping, inability to close the right eye, and loss of taste on the anterior two-thirds of the tongue. On examination, the forehead is involved and Bell's phenomenon is absent. She denies ear pain, vesicles, or hearing loss. MRI brain is normal. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis: Bell's Palsy This patient presents with **idiopathic facial nerve palsy (Bell's palsy)** — the most common cause of acute unilateral facial paralysis. ### Diagnostic Features Present - **Sudden onset** of complete unilateral facial paralysis - **Forehead involvement** (distinguishes CN VII palsy from central lesion) - **Loss of taste** on anterior 2/3 of tongue (chorda tympani involvement) - **Inability to close eye** with absent Bell's phenomenon (orbicularis oculi paralysis) - **Normal neuroimaging** (MRI excludes stroke, tumor, demyelination) - **No vesicles or otitis** (excludes Ramsay Hunt syndrome) ### Management Algorithm ```mermaid flowchart TD A[Acute unilateral facial paralysis]:::outcome --> B{Forehead involved?}:::decision B -->|No| C[Central lesion - Investigate]:::action B -->|Yes| D{Vesicles or ear pain?}:::decision D -->|Yes| E[Ramsay Hunt - Antivirals + Steroids]:::action D -->|No| F{Time since onset?}:::decision F -->|Within 72 hours| G[Start Prednisolone 1 mg/kg/day]:::action F -->|After 72 hours| H[Consider antivirals if severe]:::action G --> I[Eye care: lubricant, taping, eye patch]:::action I --> J[Electrophysiology if no recovery at 3-4 weeks]:::outcome ``` **Key Point:** Corticosteroids within 72 hours of onset reduce the risk of incomplete recovery by ~50% in Bell's palsy. The evidence is strongest when started within 48–72 hours. **High-Yield:** Bell's palsy accounts for 60–75% of acute facial nerve palsies. Prednisolone 1 mg/kg/day (max 80 mg) for 7 days, then taper over 7 days, is the standard regimen [cite:Harrison 21e Ch 379]. **Clinical Pearl:** Eye care is as important as medical therapy. Patients must use artificial tears, protective eyewear, and eye taping at night to prevent exposure keratopathy and corneal ulceration. **Warning:** Do NOT assume all facial palsies are Bell's palsy — always check for vesicles (Ramsay Hunt), parotid mass, otitis media, or CNS signs before attributing to idiopathic nerve dysfunction. ### Why Imaging Is Not First-Line - MRI brain is already normal, excluding structural lesion - CT temporal bone is reserved for suspected fracture, cholesteatoma, or chronic otitis — not present here - Normal imaging in a typical presentation supports Bell's palsy diagnosis