What is the significance of reflex presentation in patients with paraplegia?

Significance of Reflex Presentation in Paraplegia

The pattern of reflex presentation in patients with paraplegia is critical for determining the level and completeness of spinal cord injury, predicting recovery potential, and guiding rehabilitation strategies.

Types of Reflexes in Paraplegia

Deep Tendon Reflexes (DTRs)

• Hyperreflexia (increased reflexes): Typically indicates an upper motor neuron (UMN) lesion above the level of reflex testing

  • Characterized by brisk, exaggerated responses
  • Often accompanied by spasticity and positive Babinski sign
  • Suggests spinal cord injury with preservation of reflex arcs below the level of injury

• Hyporeflexia/Areflexia (decreased/absent reflexes): May indicate:

  • Lower motor neuron (LMN) injury at the level being tested
  • Spinal shock phase (temporary phenomenon immediately after injury)
  • Complete transection at or below the level being tested

Pathological Reflexes

• Babinski sign: Upgoing toe response indicates UMN lesion
• Clonus: Sustained rhythmic contractions when a muscle is suddenly stretched

Clinical Significance of Reflex Patterns

1. Diagnostic Value

• Level of injury determination:

  • Reflexes help localize the neurological level of injury (NLI)
  • Preservation of reflexes below injury level with absence of voluntary movement suggests complete UMN lesion 1

• Completeness assessment:

  • Complete paraplegia: Total loss of motor and sensory function below injury level with hyperreflexia after spinal shock resolves
  • Incomplete paraplegia (paraparesis): Some preservation of motor/sensory function below injury level with variable reflex presentation 2

2. Prognostic Value

• Recovery potential indicators:

  • Return of reflexes after spinal shock may indicate potential for neurological recovery
  • Patients with injuries at or below T9 have better potential for lower extremity motor recovery (38%) compared to those with injuries above T9 3
  • Approximately 20% of patients with initial neurological level at or below T12 may regain sufficient hip flexor and knee extensor strength to achieve functional ambulation 3

• Conversion from complete to incomplete status:

  • Late conversion (>4 months post-injury) from complete to incomplete status occurs in approximately 4% of patients 3
  • This is associated with improved functional outcomes, including potential for ambulation

3. Monitoring for Complications

• Autonomic dysreflexia detection:

  • Hyperreflexia may be an early sign of autonomic dysreflexia in patients with injuries at T6 or above
  • Requires immediate intervention to prevent dangerous blood pressure elevation

• Spasticity assessment:

  • Degree of hyperreflexia correlates with severity of spasticity
  • Guides management decisions for antispasmodic medications or interventions

Special Reflex Presentations

Spinal Shock Phase

• Immediately after injury: Flaccid paralysis with areflexia below injury level
• Duration: Typically 24-72 hours, but can last weeks
• Resolution: Gradual return of reflexes, often becoming hyperactive
• Significance: Temporary phenomenon; final reflex status emerges after resolution

Conus Medullaris/Cauda Equina Injury

• Presents with LMN pattern: Hyporeflexia/areflexia
• May have mixed UMN/LMN signs depending on exact level
• Typically affects S2-S4 reflexes (bulbocavernosus, anal wink)
• Poorer prognosis for bowel/bladder function recovery

Variants and Atypical Presentations

Paraplegia with Preserved Reflexes

• Some patients with pure motor variants may maintain normal or exaggerated reflexes throughout disease course 1
• This pattern is seen in certain conditions like hereditary spastic paraplegia

Hepatic Myelopathy

• Characterized by severe motor abnormalities with progressive spasticity
• Presents with hyper-reflexia despite relatively mild mental alterations
• Often associated with long-standing portocaval shunting
• May reverse with liver transplantation 1

Clinical Pitfalls in Reflex Assessment

• Examiner and patient factors can make DTR assessment less objective 4
• Left-right differences should be carefully noted as they may indicate asymmetrical pathology
• Sedative medications can suppress reflex responses and confound assessment
• Jendrassik maneuver can be used to reinforce and detect subtle reflexes

Terminology Considerations

The term "incomplete paraplegia" has been used in literature to describe clinical situations classically described as "paraparesis." For clarity:

• Paraplegia: Complete loss of motor function in lower limbs
• Paraparesis: Partial preservation of motor function in lower limbs 2

Patients with any preservation of motor strength below the injury level should be described as paraparetic rather than as having incomplete paraplegia to avoid confusion 2.

By carefully assessing and documenting reflex patterns in patients with paraplegia, clinicians can better determine prognosis, guide rehabilitation strategies, and monitor for complications or neurological changes over time.