Subtypes of Narcolepsy
Updated DSM-5 (2013) coding procedures for various narcolepsy subtypes:
- Narcolepsy without cataplexy but with hypocretin deficiency – most common
- Autosomal dominant cerebellar ataxia, deafness, and narcolepsy – caused by a DNA mutations and is characterized by later age of onset (e.g., 40 years old) deafness, cerebellar ataxia, and eventually dementia
- Autosomal dominant narcolepsy, obesity, and type 2 diabetes (narcolepsy, obesity, and type 2 diabetes and low CSF hypocretin-1 levels have been described in rare cases and are associated with a glycoprotein gene mutation)
- Narcolepsy with cataplexy but without hypocretin deficiency – rare subtype, seen in less than 5% of narcolepsy cases
- Narcolepsy secondary to another medical condition – narcolepsy develops secondary to an infectious disease (Whipple’s disease, sarcoidosis), or alternatively, to a traumatic or tumor induced medical condition responsible for destroying hypocretin neurons. For this subtype, a clinician would first code the underlying medical condition (e.g., 040.2 Whipple’s disease; 347.10 narcolepsy secondary to Whipple’s disease).