Diagnostic ambiguities in a case of post-traumatic narcolepsy with cataplexy

Narcolepsy arising from trauma can present particular problems of differential diagnosis. In this case study presentation the patient suffered a head trauma, without unconsciousness, and began to experience unusual episodic behaviours. Symptom presentation differed from the typical clinical manifestations of idiopathic narcolepsy leading to an 8-year search for a definitive diagnosis. Key relevant aspects that led to diagnostic ambiguities were the order of symptom development, negative for the antigen HLA DR2, significance of the Multiple Sleep Latency Test (MSLT) mean sleep latency versus number of sleep onset rapid eye movement periods, the somewhat atypical features of cataplexy, the coexistence of sleep apnoea, and the mildness of the original head injury. It is argued that cases of post-traumatic narcolepsy should be considered in the context of their clinical development over time and that practitioners should be aware that this form of narcolepsy can differ from the typical clinical history of idiopathic narcolepsy.