Primary hypersomnia

This code signifies a chronic neurological sleep disorder characterized by excessive daytime sleepiness that is not attributable to insufficient sleep, another medical condition, medication, or substance use. Individuals with this condition experience prolonged and unrefreshing sleep episodes, often struggling to wake up and feeling drowsy throughout the day.

Apply this code when documentation clearly indicates a diagnosis of primary hypersomnia, also known as idiopathic hypersomnia. This diagnosis is typically made after polysomnography and multiple sleep latency tests rule out other causes of excessive daytime sleepiness, such as narcolepsy or sleep apnea.

• Ensure documentation explicitly states "primary hypersomnia" or "idiopathic hypersomnia" to support this specific code.
• Do not use this code for hypersomnia due to a medical condition (e.g., F51.12), drug or substance (e.g., F51.13), or other specified causes.
• Always review the patient's full medical record to confirm that all secondary causes of hypersomnia have been investigated and ruled out.