title: Diagnosis and treatment of hyponatraemia in neurosurgical patients.
abstract: Hyponatraemia is the most common electrolyte imbalance in neurosurgical patients. Acute hyponatraemia is particularly common in neurosurgical patients after any type of brain insult, including brain tumours and their treatment, pituitary surgery, subarachnoid haemorrhage or traumatic brain injury. Acute hyponatraemia is an emergency condition, as it leads to cerebral oedema due to passive osmotic movement of water from the hypotonic plasma to the relatively hypertonic brain which ultimately is the cause of the symptoms associated with hyponatraemia. These include decreased level of consciousness, seizures, non-cardiogenic pulmonary oedema or transtentorial brain herniation. Prompt treatment is mandatory to prevent such complications, minimize permanent brain damage and therefore permit rapid recovery after brain insult. The infusion of 3% hypertonic saline is the treatment of choice with different rates of administration based on the severity of symptoms and the rate of drop in plasma sodium concentration. The pathophysiology of hyponatraemia in neurotrauma is multifactorial; although the syndrome of inappropriate antidiuresis (SIADH) and central adrenal insufficiency are the commonest causes encountered. Fluid restriction has historically been the classical treatment for SIADH, although it is relatively contraindicated in some neurosurgical patients such as those with subarachnoid haemorrhage. Furthermore, many cases admitted have acute onset hyponatraemia, who require hypertonic saline infusion. The recently developed vasopressin receptor 2 antagonist class of drug is a promising and effective tool but more evidence is needed in neurosurgical patients. Central adrenal insufficiency may also cause acute hyponatraemia in neurosurgical patients; this responds clinically and biochemically to hydrocortisone. The rare cerebral salt wasting syndrome is treated with large volume normal saline infusion. In this review, we summarize the current evidence based on the clinical presentation, causes and treatment of different types of hyponatraemia in neurosurgical patients.
authors.affiliation: Academic Department of Endocrinology, Beaumont Hospital/RCSI Medical School, Dublin, Ireland.
authors.forename: Martín
authors.initials: M
authors.lastname: Cuesta
authors.affiliation: Academic Department of Endocrinology, Beaumont Hospital/RCSI Medical School, Dublin, Ireland.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Hannon
authors.affiliation: Academic Department of Endocrinology, Beaumont Hospital/RCSI Medical School, Dublin, Ireland. Electronic address: christhompson@beaumont.ie.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Thompson
mesh_terms: D000309:Adrenal Insufficiency / Q000150:complications; D000324:Adrenocorticotropic Hormone / Q000172:deficiency; D065092:Antidiuretic Hormone Receptor Antagonists / Q000627:therapeutic use; D001929:Brain Edema / Q000209:etiology / Q000517:prevention & control; D000070642:Brain Injuries, Traumatic / Q000150:complications / Q000503:physiopathology; D005440:Fluid Therapy / Q000009:adverse effects; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D020896:Hypovolemia / Q000150:complications; D007177:Inappropriate ADH Syndrome / Q000150:complications; D019635:Neurosurgical Procedures / Q000009:adverse effects; D010902:Pituitary Gland / Q000503:physiopathology / Q000601:surgery; D011183:Postoperative Complications / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D012462:Saline Solution, Hypertonic / Q000627:therapeutic use*; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000503:physiopathology; D014508:Urea / Q000627:therapeutic use; D014883:Water-Electrolyte Imbalance / Q000209:etiology / Q000503:physiopathology
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D012462:Saline Solution, Hypertonic; D014508:Urea; D000324:Adrenocorticotropic Hormone
keywords: Adrenal insufficiency; Cerebral salt wasting; Hiponatremia; Hyponatremia; Insuficiencia suprarrenal; Neurocirugía; Neurosurgery; Pérdida de sal cerebral; SIADH; Síndrome de antidiuresis inapropiada