Treatment of subarachnoid haemorrhage complicated by hyponatraemia

Aneurysmal subarachnoid haemorrhage can be complicated by acute hyponatraemia in neurosurgical patients. De Oliveira Manoel et al., (2016, p. 1) define aneurysmal subarachnoid haemorrhage (SAH) as ‘a complex neurovascular syndrome with profound systemic effects and is associated with high disability and mortality’. An aneurysmal SAH is the result of cerebral aneurysm rupture or trauma, thus resulting in bleeding in the subarachnoid space. Rupture of cerebral aneurysms commonly occurs at bifurcations and branches within the Circle of Willis (Hickey 2014). Patients with a SAH commonly develop hyponatraemia within two weeks of cerebral rupture (Vrsajkov, Javanovic, Stanisavljevic, Uvelin, & Vrsajkov, 2012). Hyponatraemia is the most common electrolyte abnormality to develop in patients with a SAH. It is defined by Hickey (2014, p. 203) as ‘serum sodium less than 135mEq/L’. High-grade SAH patients with anterior circulation aneurysms have a 50% incident rate of developing acute hyponatraemia (De Oliveira Manoel et al., 2016), yet the pathophysiology linking SAH and hyponatraemia is not fully understood (De Oliveira Manoel et al., 2016; Manzanares, Aramendi, Langlois & Biestro, 2014; Mapa et al., 2016; See, Wu, Lai, Gross, & Du, 2016).