I-10 Corner: Diseases of the Nervous System (G00-G99)

on Monday, 23 June 2014. All News Items | Documentation | Coding

In this week’s article, we’re discussing a few of the changes for ICD-10-CM in the Nervous System (Chapter 6): Alzheimer’s Dementia, Epilepsy, Hemiparesis/Hemiplegia (Dominant vs. Non-Dominant), Migraine, Phantom Limb Pain and Sleep Apnea

Alzheimer’s Dementia

I-9: Alzheimer’s Dementia

  • with behavioral disturbance (aggressive) (combative) (violent) (331.0 / 294.11)
  • without behavioral disturbance (331.0 / 294.10)

The category for Alzheimer’s disease (G30) has been expanded to reflect onset (early vs. late)

I-10: Alzheimer’s Dementia

  • behavioral disturbance (G30.9 / F02.81)
  • early onset (G30.0 / F02.81)
  • late onset (G30.1 / F02.80)
  • specified NEC (G30.8 / F02.80)



Terms for Epilepsy have been updated to classify the disorder, e.g,

  • Localization-related Idiopathic Epilepsy
  • Generalized Idiopathic Epilepsy
  • Special Epileptic Syndromes


I-9: Epilepsy, epileptic (idiopathic) (345.9)

Epilepsy, localization related (focal) (partial) and (epileptic syndromes)

  • With
    • Complex partial seizures (345.4)
    • Simple partial seizures (345.5)

Within each category, more specificity can be described to identify: Seizures of Localized Onset, Complex Partial Seizures, Intractable and Status Epilepticus.

I-10: Epilepsy, epileptic, epilepsia (attack) (cerebral) (convulsion) (fit) (seizure) (G40.909)

Epilepsy, localization-related (focal) (partial)

  • Idiopathic (G40.009)
    • With seizures of localized onset (G40.009)
      • Intractable (G40.019)
        • With status epilepticus (G40.011)
        • Without status epilepticus (G40.019)
      • Not intractable (G40.009)
        • With status epilepticus (G40.001)
        • Without status epilepticus (G40.009)

Category G40, Epilepsy and Recurrent Seizures

The following terms are to be considered equivalent to intractable:

  • Pharmacoresistent (pharmacologically resistant)
  • Treatment resistant
  • Refractory (medically)
  • Poorly controlled

Hemiplegia and Hemiparesis  (Dominant vs. Non-Dominant Side)

This category is to be used only when the listed conditions are reported without further specification, or are stated to be old or longstanding but of unspecified cause. The category is also for use in multiple coding to identify these conditions resulting from any cause.                                      


The following fifth-digits are for use with codes 342.0-342.9:

  • 0 affecting unspecified side
  • 1 affecting dominant side
  • 2 affecting non-dominant side


Per ICD-10-CM Official Coding Guidelines: Codes from category G81, Hemiplegia and hemiparesis, and subcategories, G83.1, Monoplegia of lower limb, G83.2, Monoplegia of upper limb, and G83.3, Monoplegia, unspecified, identify whether the dominant or non-dominant side is affected.

Should the affected side be documented, but not specified as dominant or non-dominant, and the classification system does not indicate a default, code selection is as follows:

  • For ambidextrous patients, the default should be dominant
  • If the left side is affected, the default is non-dominant
  • If the right side is affected, the default is dominant

Example: G81.9 Hemiplegia, unspecified

  • G81.90:  Hemiplegia, unspecified affecting unspecified side
  • G81.91:  Hemiplegia, unspecified affecting right dominant side
  • G81.92:  Hemiplegia, unspecified affecting left dominant side
  • G81.93:  Hemiplegia, unspecified affecting right non-dominant side
  • G81.94:  Hemiplegia, unspecified affecting left non-dominant side

            Excludes1: Hemiplegia and hemiparesis due to sequela of cerebrovascular disease


I-9: Migraine, Unspecified (Idiopathic) (346.9x)

I-10: Migraine, Unspecified (Idiopathic) (G43.909)


Category G43, Migraine

The following terms are to be considered equivalent to intractable:

  • Pharmacoresistent (pharmacologically resistant)
  • Treatment resistant
  • Refractory (medically)
  • Poorly controlled


Phantom Limb

The sensation that an amputated or missing limb is still attached to the body and is moving along with other body parts. An estimated 60% to 80% of people that have had an amputation, experience phantom sensations in the amputated limb with the majority being painful.  

I-9: Phantom limb (syndrome) (353.6)


I-10 has given us the ability to identify whether pain is present or not after an amputation.

I-10: Phantom limb syndrome (G54.7)

  • with pain (G54.6)
  • without pain (G54.7)


Sleep Apnea

Sleep Apnea has its own subcategory with fifth character specificity identifying the type


I-9: Sleep Apnea, Unspecified (780.57)

  • with
    • Hypersomnia, unspecified (780.53)
    • Hyposomnia, unspecified (780.51)
    • Insomnia, unspecified (780.51)
    • Sleep disturbance (780.57)
  • Central, in conditions classified elsewhere (327.27)
  • Obstructive (adult) (pediatric) (327.23)
  • Organic (327.20)
    • other (327.29)
  • Primary central (327.21)

I-10: Sleep Apnea, Unspecified (G47.30)

  • Central (primary) (G47.31)
    • in conditions classified elsewhere (G47.37)
  • Obstructive (adult) (pediatric) (G47.33)
  • Primary central (G47.31)
  • Specified NEC (G47.39)

As you can see, there are several new terms and descriptions in the Nervous System Chapter for I-10-CM, providing more specificity and better clarity of certain conditions. If we can take just a little extra time assigning diagnosis codes for I-10, we will reflect the true severity of illness (SOI) for each and every patient.

Article by Susie James

Susie James, RHIT, CCS, AHIMA-approved ICD-10 Trainer is the Manager of Inpatient Coding Services at MMP. Susie has worked in the coding field for over twenty-seven years and has worked as a coder, coding supervisor, and corporate coding manager for a large multi-facility system in Birmingham. She also worked for Alabama Quality Assurance Foundation (AQAF) as a coding reviewer/auditor before joining the team at Medical Management Plus. Susie is currently serving as the President of the Alabama Association of Health Information Management (AAHIM) on the Board of Directors. She is also a member of the American Health Information Management Association (AHIMA). She currently serves as a member of AHIMA’s Envisioning and Collaborative Team and recently served as a facilitator at AHIMA’s National Convention in Atlanta Georgia. You may contact Susie at This email address is being protected from spambots. You need JavaScript enabled to view it..

This material was compiled to share information. MMP, Inc. is not offering legal advice. Every reasonable effort has been taken to ensure the information is accurate and useful.


ICD-10-CM Coding Book by Ingenix

AHIMA ICD-10-CM Training Manual


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