Facial Nerve Paralysis

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Facial Nerve Anatomy & Basics - Nerve Nuances

  • Nuclei (Pons): Motor, Sup. Salivatory (parasymp), NTS (sensory).
  • Functions: Motor (face), Glands (lacrimal, submandibular/lingual), Taste (ant. 2/3 tongue). 📌 FACE-L: Facial expression, Acoustic reflex, Chorda, Eye closure, Lacrimation.
  • Course: CPA → IAM → Facial Canal (geniculate ganglion) → Stylomastoid foramen.
  • Branches (in canal):
    • Greater Petrosal (lacrimation)
    • N. to Stapedius (stapedial reflex)
    • Chorda Tympani (taste, salivation) Facial Nerve Course and Intratemporal Branches

⭐ Labyrinthine segment: narrowest part of facial canal (~0.68mm), prone to compression in Bell's Palsy.

Causes & Localization of FNP - Culprit Countdown

  • Common Culprits (Causes):

    • Idiopathic: Bell's Palsy (most frequent, >70%).
    • Infections: Ramsay Hunt (VZV), Otitis Media, Lyme.
    • Trauma: Temporal bone # (longitudinal/transverse).
    • Neoplastic: Acoustic neuroma, parotid tumors.
  • Pinpointing the Lesion (LMN Topodiagnosis):

    • UMN vs LMN: UMN spares forehead; LMN affects entire hemiface.

    Facial Nerve Anatomy and Localization Points

⭐ Bell's Palsy is a diagnosis of exclusion; always rule out sinister causes like tumors, especially in atypical/progressive FNP or recurrent FNP on the same side.

Clinical Evaluation & Grading - Face Facts

  • History: Onset (sudden?), otalgia, vesicles (HZV), hearing loss, vertigo, trauma.
  • Exam:
    • Otoscopy: Check for vesicles, AOM.
    • Differentiate UMN (forehead spared) vs LMN paralysis.
    • Assess facial zones: Forehead, Eyes (Bell's phenomenon, closure), Mouth (smile, pucker).
    • Facial Nerve Paralysis Symptoms and Nerve Location
  • Grading: House-Brackmann (HB) Scale:
    • I: Normal
    • II: Mild
    • III: Moderate
    • IV: Mod-Severe
    • V: Severe
    • VI: Total

⭐ In LMN paralysis, Bell's phenomenon (upward outward rolling of eyeball on attempted eye closure) is present.

Key Syndromes & Management - Nerve Navigators

  • Bell's Palsy: Most common, idiopathic LMN type.
    • Sudden, unilateral.
    • Rx:
      • Corticosteroids (Prednisolone 1 mg/kg/day, max 60-80 mg, 7-10 days, taper). Start <72h.
      • +/- Antivirals (Valacyclovir 1g TID / Acyclovir 400mg 5x/day, 7 days) if severe.
      • Eye care (lubrication, patching).
  • Ramsay Hunt Syndrome (Herpes Zoster Oticus): VZV origin.
    • Facial palsy + otalgia + vesicles (ear/mouth). 📌 Pain, Palsy, Pox.
    • Rx: Antivirals + Corticosteroids. Worse prognosis vs Bell's.
  • Other Causes: Trauma (e.g., temporal bone #), Tumors, Infections (e.g., AOM, Lyme), Systemic (e.g., Sarcoidosis, GBS).
  • General Rx:
    • Grade severity (House-Brackmann).
    • Corneal protection.
    • Physiotherapy.
    • Surgery (select cases: trauma, unresponsive Bell's).

⭐ For Bell's Palsy, corticosteroids initiated within 72 hours of onset yield maximal benefit.

Facial Nerve Paralysis Clinical Features

Prognosis & Complications - Future Face

  • Prognosis: Varies by cause, severity (House-Brackmann). Bell's: 85% recovery. ENoG >90% degeneration = poor.
  • Complications:
    • Corneal ulcers (exposure keratitis)
    • Synkinesis (miswiring)
    • Crocodile tears (gustatory lacrimation)
    • Contractures

⭐ Synkinesis, due to aberrant nerve regeneration, is a common long-term complication.

High‑Yield Points - ⚡ Biggest Takeaways

  • Bell's palsy: most common LMN facial paralysis, often idiopathic/viral (HSV-1).
  • Ramsay Hunt syndrome (Herpes Zoster Oticus): facial palsy, ear pain, vesicles in auricle/EAC.
  • House-Brackmann grading is standard for facial nerve function assessment.
  • UMN lesions spare the forehead (bilateral innervation); LMN lesions affect the entire hemiface.
  • Temporal bone fractures, especially transverse type, carry a high risk of facial nerve injury.
  • Management: Corticosteroids (e.g., prednisolone) are mainstay for Bell's palsy; antivirals controversial. Eye care is crucial to prevent corneal complications.

Practice Questions: Facial Nerve Paralysis

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In Ramsay Hunt syndrome, the most commonly involved nerve is?

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Flashcards: Facial Nerve Paralysis

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Treatment of ANOM must include IV antibiotics for a minimum of _____ days.

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Treatment of ANOM must include IV antibiotics for a minimum of _____ days.

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