What is the approach to a patient with paresis or plegia?

Approach to Paresis/Plegia

Begin with a focused history and physical examination to determine whether the weakness is central versus peripheral, unilateral versus bilateral, and acute versus gradual onset—this immediately narrows your differential and guides all subsequent testing. 1

Initial Clinical Assessment

Critical History Elements

• Timing of onset: Acute onset (<72 hours) suggests Bell's palsy, stroke, or Guillain-Barré syndrome, while gradual progression suggests neoplasm or infection 1, 2

• Distribution pattern:

  • Unilateral facial weakness involving forehead = Bell's palsy 1
  • Ascending symmetric paralysis = Guillain-Barré syndrome 2
  • Hemiparesis = stroke or central lesion 3
  • Paraplegia (lower limbs) = spinal cord lesion T2-S1 4
  • Tetraplegia (all four limbs) = spinal cord lesion C1-T2 4

• Red flag symptoms indicating NOT Bell's palsy: Dizziness, dysphagia, diplopia, hyperacusis, or involvement of other cranial nerves—these mandate workup for stroke, brainstem pathology, or Guillain-Barré 1, 2

Physical Examination Priorities

• Document all cranial nerve function to exclude multi-nerve involvement 1
• Test for central versus peripheral pattern: Central lesions spare the forehead in facial weakness; peripheral lesions (Bell's palsy) involve the entire hemiface 1
• Assess for associated neurologic deficits: Any additional deficits beyond isolated facial or limb weakness require expanded differential 2

Diagnostic Testing Algorithm

When to AVOID Testing

• Do NOT obtain routine laboratory testing for new-onset Bell's palsy 1
• Do NOT perform routine diagnostic imaging for typical Bell's palsy or Guillain-Barré presentations 1, 2

When Testing IS Indicated

For Facial Paresis/Paralysis:

• Imaging (brain MRI with contrast) is indicated when: atypical features present, gradual onset, other neurological deficits, or concern for tumor/stroke 3, 2
• Electrodiagnostic testing may be offered for complete facial paralysis to guide prognosis 1
• Lyme serology in endemic areas 3

For Limb Paresis/Paralysis:

• CSF analysis is essential for suspected Guillain-Barré (look for albumino-cytological dissociation) 2
• Electrodiagnostic studies (EMG/NCS) to distinguish between paralytic syndromes and confirm Guillain-Barré (prolonged/absent F-waves, conduction block) 2
• Brain and spine MRI with contrast for unilateral paresthesias/weakness without clear peripheral cause 3
• Targeted laboratory testing only when metabolic or electrolyte causes suspected 2
• MOG antibody testing for recurrent neurological symptoms, especially with optic neuritis or myelitis 3

Immediate Management Based on Diagnosis

Bell's Palsy (Confirmed)

• Prescribe oral steroids within 72 hours of symptom onset for patients ≥16 years old 1, 3
• Implement eye protection immediately for impaired eye closure (artificial tears, eye patch, taping) 1, 3
• May offer oral antiviral therapy in addition to steroids within 72 hours (optional, not as monotherapy) 1
• Do NOT prescribe antiviral therapy alone 1

Suspected Guillain-Barré Syndrome

• Do NOT wait for antibody results or CSF protein elevation before initiating treatment—treatment delay worsens outcomes 2
• Immediate neurological consultation required 2

Suspected Stroke

• Immediate neurological consultation and appropriate imaging 3
• Screen for stroke risk factors: hypertension, diabetes, smoking, family history 3

Mandatory Follow-Up and Referral Triggers

Reassess or refer to specialist for:

• New or worsening neurological findings at any point 1, 3
• Ocular symptoms developing at any point 1, 3
• Incomplete facial recovery 3 months after initial symptom onset 1
• Persistent limb weakness or incomplete recovery 3
• Bilateral facial involvement 5

Common Pitfalls to Avoid

• Do not diagnose Bell's palsy if other neurological deficits are present—this requires consideration of stroke, Guillain-Barré, or brainstem pathology 2
• Do not miss the 72-hour window for steroid administration in Bell's palsy—efficacy diminishes significantly after this timeframe 1, 3
• Do not overlook eye protection—corneal exposure can cause permanent vision loss 1, 3
• Do not assume all facial weakness is Bell's palsy—approximately 30% of facial paralysis cases have other underlying causes including tumor, infection, or trauma 1
• Be vigilant for necrotizing infections in immunocompromised patients with facial symptoms—these require immediate antibiotic treatment 3