Background Kleine-Levin syndrome (KLS) is a rare sleep disorder characterised by recurrent episodes of hypersomnia, cognitive impairment and behavioural changes. The aetiology is unclear, but current opinion focuses on dysfunction within diencephalic pathways. In our experience patients and their relatives often describe severe headache, photophobia and phonophobia during episodes. However headache and other migrainous symptoms are infrequently described in case reports and are not mentioned in the ICSD-2 classification.

Aims and objectives: Migraine as a risk marker, a symptomatic feature or an aetiological factor may have been overlooked in the characterisation of KLS. The aim of this study was to investigate the frequency and features of migraine in eleven KLS patients.

Methods A proforma was created to identify typical migrainous symptoms and associations. Interviews were conducted by telephone. Collateral histories were obtained to complete clinical pictures, which can be distorted by amnesia.

Results Seven patients (64%) experienced migraine between KLS episodes. Atypical and migrainous features of KLS identified during episodes included: headache (73%), photophobia (55%), phonophobia (55%) and nausea (27%). Mean KLS episode duration was 30.4 days in the migraine group vs 12.8 days in the non-migraineurs.

Conclusions The association with migraine deserves further investigation, not only as a reliable risk marker but for exploration of the pathophysiology of KLS and novel therapeutic avenues. Initial use of triptans in two of our patients has yielded encouraging results. We encourage others to look for signs of migraine in their patients and consider the use of appropriate therapy.