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⚡ Chapter 6 · G00-G99

Nervous System Diagnosis Codes

Nervous system codes cover conditions affecting your brain, spinal cord, and peripheral nerves. This includes epilepsy, Parkinson's disease, multiple sclerosis, migraines, and sleep disorders. Many of these conditions require long-term specialist care.

About This Chapter

Chapter 6 of the ICD-10-CM classification covers diseases of the nervous system, spanning codes G00-G99. These codes are used by healthcare providers to document diagnoses in your electronic health record (EHR), on insurance claims, and on medical bills.

Why this matters: If you see a code starting with G on your medical bill or health records, it likely falls in this chapter. Understanding what chapter your code belongs to can help you make sense of your diagnosis and ask better questions at your next appointment.

Diagnosis Codes in This Chapter

Browse the 44 diagnosis codes we currently cover in this chapter. Select any code to read a plain-English explanation.

G10Huntington Disease G12.21Amyotrophic Lateral Sclerosis (ALS)... G20Parkinson Disease G24.9Dystonia, Unspecified G25.81Restless Legs Syndrome G30.0Alzheimer Disease with Early Onset... G30.9Alzheimer Disease, Unspecified G31.84Mild Cognitive Impairment G35Multiple Sclerosis G37.9Demyelinating Disease of Central Nervous Sy... G40.909Epilepsy, Unspecified G43.001Migraine Without Aura, with Status Migrai... G43.009Migraine Without Aura G43.101Migraine With Aura, with Status Migrainos... G43.109Migraine With Aura G43.401Hemiplegic Migraine G43.819Other Migraine Without Status Migrainosus... G43.909Migraine, Unspecified G43.C0Periodic Headache Syndromes G43Migraine G44.1Vascular Headache G44.209Tension-Type Headache G47.00Insomnia, Unspecified G47.10Hypersomnia, Unspecified G47.30Sleep Apnea, Unspecified G47.33Obstructive Sleep Apnea G47.411Narcolepsy with Cataplexy G50.0Trigeminal Neuralgia G51.0Bell Palsy (Facial Nerve Palsy) G54.0Brachial Plexus Disorders G56.00Carpal Tunnel Syndrome G57.00Sciatica G58.9Mononeuropathy, Unspecified G61.0Guillain-Barre Syndrome G62.9Polyneuropathy, Unspecified G70.00Myasthenia Gravis G71.0Muscular Dystrophy G72.9Myopathy, Unspecified G80.9Cerebral Palsy, Unspecified G89.29Other Chronic Pain G89.4Chronic Pain Syndrome G90.9Disorder of Autonomic Nervous System... G93.40Encephalopathy, Unspecified G95.9Disease of Spinal Cord, Unspecified...