G40-G47
Medium Complexity
Episodic and paroxysmal disorders
Primary Specialty: Neurology
Last Updated: 2025-09-10
ICD-10 Codes (194)
194 billable0 category headers
G43Billable
G43.0Billable
G43.00Billable
G43.001Billable
G43.009Billable
G43.01Billable
G43.011Billable
G43.019Billable
G43.1Billable
G43.10Billable
G43.101Billable
G43.109Billable
G43.11Billable
G43.111Billable
G43.119Billable
G43.4Billable
G43.40Billable
G43.401Billable
G43.409Billable
G43.41Billable
G43.411Billable
G43.419Billable
G43.5Billable
G43.50Billable
G43.501Billable
G43.509Billable
G43.51Billable
G43.511Billable
G43.519Billable
G43.6Billable
G43.60Billable
G43.601Billable
G43.609Billable
G43.61Billable
G43.611Billable
G43.619Billable
G43.7Billable
G43.70Billable
G43.701Billable
G43.709Billable
G43.71Billable
G43.711Billable
G43.719Billable
G43.8Billable
G43.80Billable
G43.801Billable
G43.809Billable
G43.81Billable
G43.811Billable
G43.819Billable
G43.82Billable
G43.821Billable
G43.829Billable
G43.83Billable
G43.831Billable
G43.839Billable
G43.9Billable
G43.90Billable
G43.901Billable
G43.909Billable
G43.91Billable
G43.911Billable
G43.919Billable
G44Billable
G44.0Billable
G44.00Billable
G44.001Billable
G44.009Billable
G44.01Billable
G44.011Billable
G44.019Billable
G44.02Billable
G44.021Billable
G44.029Billable
G44.03Billable
G44.031Billable
G44.039Billable
G44.04Billable
G44.041Billable
G44.049Billable
G44.05Billable
G44.051Billable
G44.059Billable
G44.09Billable
G44.091Billable
G44.099Billable
G44.1Billable
G44.2Billable
G44.20Billable
G44.201Billable
G44.209Billable
G44.21Billable
G44.211Billable
G44.219Billable
G44.22Billable
G44.221Billable
G44.229Billable
G44.3Billable
G44.30Billable
G44.301Billable
G44.309Billable
G44.31Billable
G44.311Billable
G44.319Billable
G44.32Billable
G44.321Billable
G44.329Billable
G44.4Billable
G44.40Billable
G44.41Billable
G44.5Billable
G44.51Billable
G44.52Billable
G44.53Billable
G44.59Billable
G44.8Billable
G44.81Billable
G44.82Billable
G44.83Billable
G44.84Billable
G44.85Billable
G44.86Billable
G44.89Billable
G45Billable
G45.0Billable
G45.1Billable
G45.2Billable
G45.3Billable
G45.4Billable
G45.8Billable
G45.9Billable
G46Billable
G46.0Billable
G46.1Billable
G46.2Billable
G46.3Billable
G46.4Billable
G46.5Billable
G46.6Billable
G46.7Billable
G46.8Billable
G47Billable
G47.0Billable
G47.00Billable
G47.01Billable
G47.09Billable
G47.1Billable
G47.10Billable
G47.11Billable
G47.12Billable
G47.13Billable
G47.14Billable
G47.19Billable
G47.2Billable
G47.20Billable
G47.21Billable
G47.22Billable
G47.23Billable
G47.24Billable
G47.25Billable
G47.26Billable
G47.27Billable
G47.29Billable
G47.3Billable
G47.30Billable
G47.31Billable
G47.32Billable
G47.33Billable
G47.34Billable
G47.35Billable
G47.36Billable
G47.37Billable
G47.39Billable
G47.4Billable
G47.41Billable
G47.411Billable
G47.419Billable
G47.42Billable
G47.421Billable
G47.429Billable
G47.5Billable
G47.50Billable
G47.51Billable
G47.52Billable
G47.53Billable
G47.54Billable
G47.59Billable
G47.6Billable
G47.61Billable
G47.62Billable
G47.63Billable
G47.69Billable
G47.8Billable
G47.9Billable
Updates & Changes
FY 2026 Updates
Current Year
Deleted Codes
No codes deleted in this range for FY 2026
No significant changes for FY 2026
This range maintains stability with current coding practices
Historical Changes
- •FY 2025: Routine maintenance updates with minor terminology clarifications
- •FY 2024: Enhanced specificity requirements for certain code ranges
- •FY 2023: Updated documentation guidelines for improved clarity
Upcoming Changes
- •Proposed updates pending review by Coordination and Maintenance Committee
- •Under consideration: Enhanced digital health integration codes
Implementation Guidance
- •Review all FY 2026 updates for G40-G47 codes before implementation
- •Always verify the most current codes in the ICD-10-CM manual
- •Ensure clinical documentation supports the selected diagnosis codes
- +3 more guidance items...
Range Overview
high priority
The G40-G47 range in the ICD-10 code set is dedicated to episodic and paroxysmal disorders. This range includes conditions such as epilepsy, migraines, sleep disorders, and transient cerebral ischemic attacks. These codes are used to document diagnoses for patients experiencing intermittent or sudden occurrences of symptoms, often involving the nervous system.
Key Usage Points:
- •G40 codes are used for various forms of epilepsy and recurrent seizures.
- •G43 codes are used for migraines, including with or without aura.
- •G47 codes cover sleep disorders, including insomnia, hypersomnia, sleep apnea, and circadian rhythm disorders.
- •Transient cerebral ischemic attacks are coded under G45.
- •G44 codes are used for other forms of headache, excluding migraines.
Coding Guidelines
When to Use:
- ✓When a patient is diagnosed with epilepsy, regardless of the specific type.
- ✓When a patient presents with symptoms of a sleep disorder, such as sleep apnea or insomnia.
- ✓When a patient experiences a transient ischemic attack.
- ✓When a patient is diagnosed with a migraine, either with or without aura.
- ✓When a patient presents with a headache not classified as a migraine.
When NOT to Use:
- ✗When a patient's symptoms are better explained by another diagnosis.
- ✗When a patient's headache is due to a known cause, such as a head injury.
- ✗When a patient's sleep issues are due to a known cause, such as a psychiatric disorder.
- ✗When a patient's seizures are due to a known cause, such as alcohol withdrawal.
- ✗When a patient's transient symptoms are not due to a cerebral ischemic attack.
Code Exclusions
Always verify exclusions by cross-referencing the patient's symptoms and medical history.
Documentation Requirements
Proper documentation for G40-G47 codes should include a clear diagnosis, details of the patient's symptoms, the frequency and duration of episodes, and any known triggers or exacerbating factors. Any relevant test results should also be included.
Clinical Information:
- •Clear diagnosis of the condition
- •Detailed description of the patient's symptoms
- •Frequency and duration of episodes
- •Known triggers or exacerbating factors
- •Relevant test results
Supporting Evidence:
- •Medical history
- •Physical examination findings
- •Laboratory or imaging results
- •Consultation notes
Good Documentation Example:
Patient diagnosed with sleep apnea after polysomnography showed episodes of apnea and hypopnea. Patient reports excessive daytime sleepiness and loud snoring. G47.33 (Obstructive sleep apnea) is coded.
Poor Documentation Example:
Patient has sleep issues. G47.9 (Sleep disorder, unspecified) is coded.
Common Documentation Errors:
- âš Not specifying the type of condition
- âš Failing to document the frequency or duration of episodes
- âš Not including relevant test results
- âš Using an unspecified code when a more specific code is available
Range Statistics
6
Total Codes
194
Billable
Complexity:
Medium
Primary Use:Clinical Documentation
Chapter:6
Coding Complexity
Medium
Complexity Rating
Coding for G40-G47 can be complex due to the need to differentiate between similar conditions, identify the specific type of condition, and determine the cause of the condition. Additionally, these codes often involve conditions with multiple episodes, which can complicate coding. Finally, the G40-G47 code set is subject to changes, requiring coders to stay up-to-date.
Key Factors:
- â–¸Differentiating between similar conditions
- â–¸Identifying the specific type of condition
- â–¸Determining the cause of the condition
- â–¸Coding for conditions with multiple episodes
- â–¸Keeping up with changes to the code set
Specialty Focus
G40-G47 codes are used across several specialties, but are most commonly used in neurology, sleep medicine, and primary care.
Primary Specialties:
Neurology
40%
Sleep Medicine
30%
Primary Care
30%
Clinical Scenarios:
- • A patient with a history of seizures is diagnosed with epilepsy after an EEG shows abnormal brain activity.
- • A patient presents with severe, throbbing headaches and is diagnosed with migraines after other causes are ruled out.
- • A patient reports difficulty falling asleep and staying asleep, and is diagnosed with insomnia after a sleep study.
- • A patient experiences a sudden episode of weakness and slurred speech, and is diagnosed with a transient ischemic attack after a CT scan shows no evidence of stroke.
- • A patient presents with chronic tension headaches not associated with any other condition.
Resources & References
There are several resources available to help with coding for G40-G47, including the official ICD-10 guidelines, clinical reference books, and educational materials.
Official Guidelines:
- ICD-10-CM Official Guidelines for Coding and Reporting
- American Academy of Neurology guidelines
- American Academy of Sleep Medicine guidelines
Clinical References:
- Harrison's Principles of Internal Medicine
- The International Classification of Sleep Disorders
Educational Materials:
- American Health Information Management Association (AHIMA) coding resources
- American Academy of Professional Coders (AAPC) coding resources
Frequently Asked Questions
How do I code for a patient with both epilepsy and migraines?
You would use separate codes for each condition. For example, you might use G40.9 for the epilepsy and G43.0 for the migraines.
What if a patient's sleep disorder is due to a psychiatric condition?
In this case, you would use a code from the F51 range, not the G47 range.