What are the causes and treatment options for a right-sided facial droop?

Right-Sided Facial Droop: Causes and Management

Acute right-sided facial droop is a stroke until proven otherwise and requires immediate activation of emergency medical services with rapid transport to a stroke-capable facility. 1

Immediate Assessment and Triage

Stroke Recognition Using Validated Tools

• Use the Cincinnati Prehospital Stroke Scale (CPSS) immediately, which has 72% probability of stroke if any single finding is abnormal (facial droop, arm drift, or abnormal speech). 1
• The CPSS demonstrates 59% sensitivity and 89% specificity when used by prehospital providers. 1
• Alternatively, the Los Angeles Prehospital Stroke Screen (LAPSS) achieves 93% sensitivity and 97% specificity. 1
• Call 911 immediately - do not delay transport for further evaluation. 1

Critical Time-Sensitive Actions

• Establish time zero: Document when symptoms began or when patient was last seen normal (if found with symptoms or woke with them). 1
• Provide cardiopulmonary support as needed - patients are at risk for aspiration, airway obstruction, and hypoventilation. 1
• Perform prehospital notification to activate stroke resources at receiving hospital. 1

Distinguishing Central vs. Peripheral Facial Nerve Palsy

Key Clinical Distinction

• Peripheral (lower motor neuron) facial palsy: Ipsilateral facial paralysis with forehead involvement - patient cannot wrinkle forehead or close eye on affected side. 1
• Central (upper motor neuron) palsy: Ipsilateral facial paralysis with forehead sparing - suggests stroke or brainstem lesion. 1

This distinction is critical because forehead involvement indicates peripheral pathology (Bell's palsy, trauma, tumor), while forehead sparing suggests stroke requiring immediate thrombolytic therapy.

Differential Diagnosis After Stroke is Ruled Out

Bell's Palsy (Most Common)

• Accounts for majority of acute peripheral facial nerve palsies. 1
• Attributed to facial nerve inflammation, possibly idiopathic or herpes simplex virus-related. 1
• Associated symptoms include pain around jaw/ear, hyperacusis, tinnitus, reduced taste, decreased lacrimation or salivation. 1
• Most patients achieve complete recovery by 6 months, hastened with steroids. 1

Other Peripheral Causes

• Trauma: Temporal bone fractures, mastoid injury (even mild trauma can cause facial nerve palsy). 2
• Tumors: Facial/vestibular schwannomas, meningiomas, parotid tumors, cholesteatomas, paragangliomas. 1
• Infection: Inflammatory disease, middle ear disease. 1
• Vascular compression: Hemifacial spasm from vascular compression of facial nerve. 1
• Guillain-Barré syndrome: Consider with bilateral weakness, areflexia, antecedent respiratory illness. 3

Brainstem/Pontine Lesions

• Infarction, vascular malformations, tumors, multiple sclerosis affecting facial nuclei in pons. 1
• Usually accompanied by additional neurologic symptoms (ataxia, diplopia, contralateral weakness). 1
• Rarely, isolated facial nerve palsy from brainstem or cortical infarct. 1

Diagnostic Imaging Algorithm

When Stroke is Suspected

• CT head without contrast is insufficient alone for facial nerve palsy evaluation. 1
• Stroke protocol imaging per institutional guidelines takes precedence.

After Stroke is Ruled Out

• MRI with contrast is first-line for evaluating facial nerve palsy to assess the entire facial nerve course from brainstem through parotid gland. 4
• High-resolution CT temporal bone is complementary to MRI for characterizing osseous structures, fractures, bony canal involvement, and presurgical anatomy. 1
• CT temporal bone with thin sections evaluates the facial nerve canal; contrast useful if infection or tumor suspected. 1
• Imaging is NOT routinely needed for typical Bell's palsy unless symptoms are atypical, recurrent, or persist 2-4 months. 1, 4

Trauma-Specific Imaging

• CT maxillofacial without contrast is first-line for facial injury from falls or trauma. 5
• Provides superior delineation of osseous and soft-tissue structures with multiplanar and 3D reconstructions. 5
• Complementary CT head if intracranial injury suspected. 5

Management After Stroke is Ruled Out

Bell's Palsy Treatment

• Corticosteroids within 72 hours of symptom onset - strongly recommended by the American Academy of Otolaryngology-Head and Neck Surgery. 4
• Eye protection is mandatory: Artificial tears, eye ointment, taping eye closed at night for incomplete eye closure. 4, 2
• Ophthalmology referral if incomplete eye closure to prevent corneal damage. 4, 2
• Follow-up within 1-2 weeks to assess improvement. 4

Traumatic Facial Nerve Palsy

• Urgent otolaryngology referral even without temporal bone fracture - edema within facial nerve may require decompressive surgery. 2
• Steroids are of questionable benefit in traumatic cases based on limited data. 2
• Eye lubrication and nighttime taping critical to prevent permanent corneal damage. 2

Laboratory Evaluation

• Complete blood count and inflammatory markers based on clinical suspicion. 4
• Consider Mycoplasma serology if antecedent respiratory illness and concern for Guillain-Barré syndrome. 3
• Check serum sodium - severe hyponatremia can cause reversible stroke-like symptoms including facial droop. 6

Critical Pitfalls to Avoid

• Never assume facial droop is benign - always rule out stroke first using validated screening tools. 1
• Do not delay imaging or treatment while obtaining detailed history - time is brain in stroke. 1
• Do not overlook eye protection in peripheral facial palsy - corneal exposure can cause permanent vision loss. 4, 2
• Do not image typical Bell's palsy routinely - reserve imaging for atypical, recurrent, or persistent cases beyond 2-4 months. 1, 4
• Do not miss temporal bone fractures - even mild mastoid trauma can cause facial nerve palsy requiring urgent ENT evaluation. 2
• Consider non-neurologic causes - severe electrolyte abnormalities, intracranial foreign bodies, and systemic infections can mimic stroke. 6, 7