Background and aims Paramyotonia congenita (PMC) is a genetic condition characterized by weakness exacerbated by exercise or cold and is also often associated with potassium-related muscle weakness. Intraspinal filum terminale lipomas can sometimes cause tethered spinal cord syndrome and may first present during childbirth by fetal head compression, positioning or epidural itself.

Results This is a 33-year-old full term parturient with clinically diagnosed PMC and terminal filum lipoma extending from L2 to sacrum with unremarkable pre-anaesthetic assessment. She underwent a plain early epidural for labour analgesia at L3/L4, which was successfully topped up for an emergency caesarean section for failure to progress. Normothermia and normokalaemia was ensured. However, she developed a 3-day prolonged paraparesis which was expectantly managed for normokalaemic periodic paralysis and self-resolved. An urgent MRI scan excluded any acute space occupying lesion.

Conclusions Our challenge lies in the lack of information and time. Our first encounter was in a semi-emergency setting on labour induction, wherein our patient had declined antepartum muscle biopsies and MRI scans. In view of a strong clinical diagnosis of PMC, we prepared for a range of muscle-related risks, e.g. cold or exercise/shivering induced myotonias, potassium-related metabolic abnormalities, rhabdomyolysis and malignant hyperthermia. Regional anaesthesia was preferred over general anaesthesia to avoid volatiles, suxamethonium and neostigmine. Tethered cord syndrome may be due to a more low-lying and posteriorly displaced cord. If associated, a plain low epidural is preferred with extensive counselling for increased risk of nerve injury. Ultimately, an early multidisciplinary approach with extra vigilance to complications is paramount.