LASH syndrome: New cases with a broadening clinical phenotype

To describe three new cases of the headache syndrome of long-lasting autonomic symptoms with hemicrania (LASH), and to establish a clinical phenotype utilizing all LASH cases noted in the medical literature.

A case series of patients was evaluated in an academic headache clinic over a two-year time period. LASH syndrome was defined by episodic headache attacks with associated cranial autonomic symptoms that start before headache onset, last the entire duration of the headache and continue on for a period of time after the headache ceases.

Three patients were noted to have LASH syndrome in a two-year time period (2017-2018). One patient was diagnosed with primary LASH, while two others had probable secondary LASH from a secretory pituitary tumor. The primary LASH patient was female. She had on average one headache per week lasting 1-3 days in duration. She experienced migrainous associated symptoms along with their cranial autonomic symptoms. She also developed a fixed Horner's syndrome along with a typical headache attack, which was present for 6 months at the time of consultation. She had complete headache relief with indomethacin and her miosis and ptosis also resolved with treatment. Secondary LASH was diagnosed in two patients (one male, one female) both with prolactin secreting pituitary microadenomas. One of the patients had his headaches abolish with dopamine agonist therapy while the other patient did not respond to hormonal modulation but became pain free on indomethacin. Secondary LASH patients had less frequent headache episodes and lacked any migrainous associated features, but exhibited agitation with headache.

LASH syndrome may be rare, but more reported cases are entering the headache literature. The temporal profile of onset and offset of cranial autonomic symptoms is key to making the diagnosis. Primary and secondary LASH may present differently based on gender predominance, the presence of migrainous associated features, and attack frequency. Secondary LASH appears to be indomethacin responsive, suggesting that medication effectiveness should not obviate the need to do testing for secondary etiologies.