What is the management approach for a patient presenting with lower motor neuron (LMN) facial palsy and Posterior Reversible Encephalopathy Syndrome (PRES)?

Management of LMN Facial Palsy with PRES

When a patient presents with lower motor neuron facial palsy in the context of PRES, the primary management priority is aggressive blood pressure control and removal of precipitating factors to reverse the PRES, while simultaneously implementing corticosteroids (if within 72 hours of facial palsy onset) and mandatory eye protection to prevent corneal damage.

Immediate Priorities: PRES Management Takes Precedence

The management must address both conditions simultaneously, but PRES represents the more immediately life-threatening condition requiring urgent intervention:

PRES-Specific Management

• Blood pressure control is the cornerstone of PRES treatment, as the syndrome occurs when elevated blood pressure exceeds the autoregulatory capacity of brain vasculature 1, 2
• Identify and remove precipitating factors including cytotoxic medications, immunosuppressants, or treat underlying conditions such as eclampsia, renal failure, sepsis, or autoimmune disorders 1, 2, 3
• Administer anticonvulsant medications if seizures occur, as seizures are a common presenting feature of PRES 1, 2, 4
• Correct metabolic abnormalities that may be contributing to the syndrome 4
• Perform frequent neurological evaluations to monitor for progression or complications 3

Critical PRES Monitoring

• Obtain MRI imaging to confirm diagnosis and assess extent of vasogenic edema, typically showing bilateral parieto-occipital subcortical white matter changes 1, 2, 3
• Monitor for secondary complications including ischemia, hemorrhage, and cerebral infarction, which can occur in severe cases 4
• Factors associated with poor PRES outcomes include altered sensorium, hypertensive etiology, hyperglycemia, longer time to control causative factors, elevated C-reactive protein, coagulopathy, extensive cerebral edema, and hemorrhage on imaging 1

Concurrent Facial Palsy Management

While addressing PRES, the facial palsy requires immediate attention to prevent permanent complications:

Corticosteroid Therapy (Time-Sensitive)

• Prescribe prednisolone 50 mg daily for 10 days OR prednisone 60 mg daily for 5 days followed by a 5-day taper if within 72 hours of facial palsy onset 5
• Evidence shows 83% recovery at 3 months with prednisolone versus 63.6% with placebo 5
• Do NOT prescribe antiviral monotherapy alone, as it is ineffective 6, 5
• Antiviral therapy may be offered in combination with steroids as an option, though benefit is minimal 5

Mandatory Eye Protection (Non-Negotiable)

• Implement eye protection immediately for all patients with impaired eye closure to prevent corneal damage, which can become permanent 6, 5
• Apply lubricating ophthalmic drops every 1-2 hours while awake 5
• Use ophthalmic ointment at bedtime for sustained moisture retention 5
• Employ eye taping or patching at night with careful instruction on proper technique to avoid corneal abrasion 5
• Recommend sunglasses outdoors for protection against foreign particles and wind 5
• Refer urgently to ophthalmology if severe impairment with complete inability to close the eye or signs of corneal exposure develop 5

Diagnostic Evaluation for Facial Palsy in PRES Context

The presence of PRES changes the diagnostic approach for facial palsy:

Atypical Features Requiring Imaging

• Obtain MRI with and without contrast given the atypical context of facial palsy occurring with PRES, as this represents a neurological presentation beyond typical Bell's palsy 5
• Assess for other cranial nerve involvement, which would suggest alternative diagnoses beyond Bell's palsy 6, 5
• Evaluate for bilateral facial weakness, which is rare in Bell's palsy and suggests alternative pathology 5

Physical Examination Priorities

• Perform comprehensive cranial nerve examination to identify additional neurological deficits 5
• Use House-Brackmann grading scale to assess severity of facial paralysis 5
• Test forehead function to confirm lower motor neuron pattern (forehead involvement distinguishes LMN from central causes) 5
• Assess eye closure capability to determine urgency of ophthalmology referral 5

Special Considerations for Combined Presentation

Corticosteroid Use in PRES Context

• While corticosteroids are strongly recommended for Bell's palsy, their use must be carefully weighed in PRES patients, particularly those with hypertensive etiology, as steroids can potentially worsen blood pressure control
• Prioritize blood pressure control first, then initiate corticosteroids if within the 72-hour window and blood pressure is adequately controlled 5

Electrodiagnostic Testing

• Consider electrodiagnostic testing (ENoG and EMG) at 3-14 days post-onset if complete facial paralysis is present, as this may help predict prognosis 5
• Testing showing >10% nerve response amplitude indicates excellent prognosis 5

Mandatory Follow-Up and Referral Triggers

Immediate Reassessment Required For:

• New or worsening neurological findings at any point (may indicate PRES progression or alternative diagnosis) 6, 5
• Development of ocular symptoms requiring urgent ophthalmology referral 6, 5
• Progressive facial weakness beyond 3 weeks, which is atypical for Bell's palsy 5

Three-Month Reassessment

• All patients with incomplete facial recovery at 3 months must be referred to a facial nerve specialist for evaluation of reconstructive options 6, 5
• Refer to ophthalmology for persistent eye closure problems 5
• Screen for depression and provide psychological support, as persistent facial paralysis significantly impacts quality of life 5

Common Pitfalls to Avoid

• Failing to prioritize PRES management can lead to permanent neurological sequelae, ischemia, hemorrhage, or death despite the facial palsy being reversible 1, 4
• Delaying corticosteroids beyond 72 hours significantly reduces effectiveness for facial palsy recovery 5
• Inadequate eye protection can result in permanent corneal damage even if facial function recovers 6, 5
• Missing atypical features such as bilateral involvement or other cranial nerve deficits that suggest diagnoses beyond simple Bell's palsy 5
• Neglecting to control blood pressure aggressively in PRES, as longer time to control causative factors is associated with poor outcomes 1