spasticity

DEFINITION of spasticity

Spasticity is a clinical symptom of Upper Motor Neuron (UMN) syndrome. Physiologically, it occurs when there is a disruption in the descending inhibitory pathways of the central nervous system (brain or spinal cord). This loss of inhibition leads to hyperexcitability of the stretch reflex arc within the muscles. A hallmark characteristic of spasticity is that it is velocity-dependent; the faster a muscle is passively stretched by an examiner, the greater the resistance encountered. Over time, untreated spasticity can lead to painful muscle spasms, severe limitations in range of motion (ROM), and permanent anatomical contractures. It is commonly seen in patients with cerebral palsy, multiple sclerosis, traumatic brain injury, spinal cord injury, and stroke.

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ETYMOLOGY of spasticity

greek - spast-: From Greek spastikos, meaning “drawing in,” “pulling,” or “tugging” (derived from span, to pull/draw).

• -ic: Suffix from Latin -icus or Greek -ikos, meaning “pertaining to.”

• -ity: Suffix from Latin -itas, meaning “the state, quality, or condition of.”

• Literal Meaning: The state or condition of drawing/pulling (referring to the tight, unyielding pull of the affected muscles).

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Coding & Documentation Nuances

• ICD-10-CM: Spasticity is rarely coded as an isolated symptom if the underlying etiology is known, as it is integral to many central nervous system disorders.

  • Chapter 6 (Nervous System): Look for combination codes that specify spasticity, such as G81.1- (Spastic hemiplegia) or G80.0 (Spastic quadriplegic cerebral palsy).

  • Chapter 13 (Musculoskeletal): If documented as a localized muscle spasm without a central nervous system etiology, it may map to M62.838 (Other muscle spasm).

• ICD-10-PCS: Spasticity itself is a condition, but it dictates the medical necessity for specific surgical and medical interventions.

  • Introduction: Intramuscular injections of botulinum toxin (Botox) to paralyze the spastic muscle. (e.g., 3E023GC - Introduction of Other Therapeutic Substance into Muscle, Percutaneous).

  • Implantation: Insertion of an intrathecal baclofen pump for severe, systemic spasticity (e.g., 00H - Insertion of device into Spinal Canal).

• CPT: Coders should look for Chemodenervation codes (e.g., 64642-64647) when Botox is used to destroy the nerve-muscle connection temporarily to relieve spasticity.

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Related Terms & Differentials

1. Rigidity: An increase in muscle tone that is not velocity-dependent (the resistance is constant regardless of how fast you stretch the limb). Typically presents as “lead-pipe” or “cogwheel” rigidity and is a sign of extrapyramidal/basal ganglia disorders like Parkinson’s disease.

2. Spasm: A sudden, involuntary, and often painful contraction of a muscle or group of muscles. While spasticity can cause spasms, a spasm is an event, whereas spasticity is a continuous state of high tone.

3. Contracture: A permanent, physical shortening of the muscle, tendon, or joint capsule preventing normal articulation. Spasticity is neurological and can be overcome (or treated with Botox); a contracture is anatomical and usually requires surgical release (e.g., tenotomy).

4. Dystonia: A movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or twisting.

5. Flaccidity: The exact opposite of spasticity. A state of completely absent muscle tone (hypotonia) and absent reflexes, typically resulting from a Lower Motor Neuron (LMN) lesion.

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Clinical Indicators

To support a diagnosis involving spasticity, a medical coder should look for the following terminology and findings in the physical exam or neuro-assessment:

• Measurement Scales: Documentation of the Modified Ashworth Scale (MAS) or Tardieu Scale scores (tools used to grade the severity of spasticity).

• Exam Findings: “Clasp-knife” phenomenon (initial resistance to movement followed by a sudden release), hyperreflexia (exaggerated deep tendon reflexes, e.g., 3+ or 4+), positive Babinski sign, or clonus (rhythmic, oscillating muscle contractions).

• Keywords: “Velocity-dependent resistance,” “increased muscle tone,” “spastic catch,” “scissoring gait.”

• Underlying UMN Lesions: Clear documentation of an Upper Motor Neuron injury (Stroke/CVA, Multiple Sclerosis, Spinal Cord Injury).

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DERIVATIONS of spasticity

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Query functionality

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Med roots Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms