2442 Central pontine myelinolysis without hyponatremia in late-stage pregnancy

Introduction Central Pontine Myelinolysis (CPM) is a demyelinating disorder affecting the central pons linked to osmotic stress and hyponatremia. Cases in pregnancy have been associated with hyperemesis gravidarum, but also with other fluctuations in electrolyte and metabolic balance.¹

Case A 22-year-old lady presented at 34 weeks (G2P0) with severe headache. Pregnancy to that date had been unremarkable and a detailed neurological examination was unremarkable. A MRI was performed revealing a central pontine lesion demonstrated by hyper-intensity on T2 and FLAIR imaging with hypo-intensity on T1 sequences, associated with significant diffusion restriction consistent with osmotic demyelination. Serum sodium level was normal at 136 mmol/L and remained so throughout her pregnancy with no other electrolyte imbalance noted.

A differential diagnosis of inflammatory, infective and ischaemic insult amongst others was considered. A spinal MRI was unremarkable and a lumbar puncture revealed a normal cell count, protein and glucose, with no oligoclonal bands. Blood pressure was controlled throughout pregnancy, and serological testing of serum FLT1/PIGF ratio did not reveal any early pre-eclampsia. The patient subsequently had a successful vaginal delivery at 36+1/40 weeks after induction of labour.

A repeat MRI performed 3 months after delivery demonstrated almost complete resolution of the pontine signal intensity with no further diffusion restriction.

Conclusion This case highlights a unique presentation of a central pontine myelinolysis in late-stage pregnancy without any identifiable secondary cause. The resolution of imaging changes post-delivery suggests that the pregnancy itself may have been a triggering or associated factor in the development of the disorder.

Reference

1. Sánchez-Ferrer ML, Prieto-Sánchez MT, Orozco-Fernández R, Machado-Linde F, Nieto-Diaz A. Central pontine myelinolysis during pregnancy: pathogenesis, diagnosis and management. J Obstet Gynaecol. 2017;37(3):273–279. doi:10.1080/01443615.2016.1244808