TABLE 1.

Evaluation of medical causes of secondary narcolepsy

Type	Specific diagnoses	Evaluation
Neoplasm	Brain tumor (hypothalamus: eg, craniopharyngioma); lymphocytic or non‐lymphocytic acute leukemia	Brain neuroimaging, complete blood count
Inflammatory	Guillain Barré syndrome; acute encephalomyelitis; multiple sclerosis; neurolupus; anti‐NMDA receptor anti‐Ma2 and anti‐aquaporin‐4 encephalitis; neurosarcoidosis; post H1N1 vaccination or infection narcolepsy	Chronology, blood and/or CSF testing for antibodies or inflammatory markers
Infectious	Infectious encephalitis; meningoencephalitis	Lumbar puncture
Traumatic	Head trauma; Diffuse axonal injury	Chronology, neuroimaging
Iatrogenic	Cerebral irradiation	Chronology
Malformation	Holoprosencephaly; callosal agenesis	Imaging during pregnancy
Genetic	Myotonic dystrophy, Prader Willi syndrome; Coffin‐Lowry syndrome; Moebius syndrome; Hereditary Sensory and Autonomic Neuropathy Type 1E (HSAN1E); Autosomal dominant cerebellar ataxia‐deafness‐narcolepsy syndrome (ADCA‐DN); mutation of the preprohypocretin	Neurological examination, DNA testing for mutations
Metabolic	Niemann‐Pick type C; Rapid‐onset obesity, hypoventilation, hypothalamic dysfunction and autonomic dysfunction (ROHHAD)	Filipin staining test; clinical, hormonal explorations, methylation analysis, cytogenetic and molecular analysis
Neurodegenerative	Parkinson's disease	Neurological examination (parkinsonism), DAT scan

The table summarizes the known medical causes of secondary narcolepsy and the typical clinical/laboratory evaluations for each type. Consideration should be given on a case‐by‐case basis to the possibility of any of these diagnoses and the need for evaluation, particularly in children presenting with possible narcolepsy.

CSF, cerebrospinal fluid; DAT, dopamine transporter positron emission tomography scan; NMDA, anti‐N‐methyl‐D‐aspartate.