What is pseudoparalysis?

What is Pseudoparalysis?

Pseudoparalysis is a clinical condition characterized by the inability to actively move a limb or body part despite intact neurological pathways and preserved passive range of motion, typically due to pain, mechanical factors, or psychological causes rather than true neurological paralysis.

Types of Pseudoparalysis

Pseudoparalysis can manifest in different clinical contexts:

1. Orthopedic Pseudoparalysis

This is most commonly described in shoulder pathology:

• Definition: Inability to actively elevate the arm above a certain threshold (typically <90° or more strictly <45°) despite full passive range of motion 1, 2, 3
• Cause: Usually associated with massive rotator cuff tears
• Key features:
  • Preserved passive motion
  • Absence of true neurological deficit
  • Often presents with anterosuperior escape (humeral head migration)
  • May involve varying degrees of pain

Recent research shows significant disagreement among experts regarding the exact definition of shoulder pseudoparalysis. A 2023 study found minimal inter-surgeon agreement (κ = 0.360) on diagnosing pseudoparalysis in patients with massive rotator cuff tears 4. Another international survey revealed weak overall agreement (κ = 0.59) among shoulder surgeons when classifying patients with pseudoparalysis based on video examinations 5.

2. Psychogenic Pseudoparalysis

• Definition: Loss of motor function with psychological rather than neurological origin
• Key features:
  • Appears as if consciousness is lost but is not truly syncope
  • Patient typically appears to be asleep but cannot be awakened
  • Attacks are not medical emergencies and will pass by themselves
  • Patients may be moved during an attack if necessary 6

3. Pseudoparalysis in Infants

Several conditions can cause pseudoparalytic presentations in infants:

• Transient dystonia of infancy: Paroxysmal episodes of abnormal upper limb posture, sometimes involving trunk and lower limb, with normal interictal examination and neuroimaging 6
• Benign myoclonus of early infancy (BMEI): Characterized by myoclonic jerks of the head and/or upper limbs that mimic infantile spasms but with preserved consciousness 6

4. Vocal Fold Pseudoparalysis

• Definition: Reduced or impaired vocal fold movement that appears to be paralysis but is due to mechanical limitations rather than neurological causes
• Key distinction: True vocal fold paralysis/paresis refers to movement impairment due to neural or muscular mechanisms, while pseudoparalysis refers to immobility from mechanical causes like joint pathology or cancer bulk effect 6

Differential Diagnosis

Pseudoparalysis must be distinguished from true paralysis caused by:

1. Neurological disorders:

   • Stroke
   • Bell's palsy (true facial nerve paralysis) 6
   • Parkinsonism syndromes 6

2. Toxic causes:

   • Acute aluminum neurotoxicity (presenting with myoclonic jerks and seizures) 6
   • Dialysis encephalopathy (with motor disturbances including twitching and myoclonic jerks) 6

Clinical Approach to Pseudoparalysis

When evaluating a patient with apparent paralysis:

1. Assess passive range of motion: Preserved passive motion with limited active motion suggests pseudoparalysis
2. Evaluate pain response: Pain-related inhibition of movement is a common cause
3. Look for mechanical factors: Joint pathology, tendon tears, or structural abnormalities
4. Consider psychological factors: Especially in cases without clear organic pathology
5. Rule out true neurological deficits: Through appropriate neurological examination

Treatment Considerations

Treatment depends on the underlying cause:

• Shoulder pseudoparalysis: Options include rotator cuff repair, margin convergence (which has shown 93% reversal of pseudoparalysis in one study 1), muscle transfers, or reverse shoulder arthroplasty
• Psychogenic pseudoparalysis: Psychological support and education about the nature of the condition
• Infant conditions: Often self-limiting and resolve with time

Pitfalls and Caveats

1. Diagnostic confusion: The lack of consensus on definition leads to inconsistent diagnosis and treatment approaches
2. Overtreatment risk: Misdiagnosing pseudoparalysis as true paralysis may lead to unnecessary interventions
3. Undertreatment risk: Dismissing symptoms as "just psychological" without thorough evaluation
4. Communication issues: The term "pseudo" may suggest to patients that their symptoms aren't real or are being fabricated, which requires careful explanation

Understanding pseudoparalysis requires recognizing that while the motor pathway is anatomically intact, functional movement is impaired due to pain, mechanical factors, or psychological mechanisms rather than true neurological damage.