Management of Fluid and Electrolyte problems in Children


Acute Hyponatraemia

Duration of less than 48 hours.

The most common setting for acute and potentially life-threatening hyponatraemia is in the intra- and post-operative setting.

There must be a source of electrolyte free water (EFW):

  • Exogenous (intravenous or oral)
  • Endogenous = desalination of intravenous or body fluids
    • Acute postoperative period
    • Cerebral salt wasting
    • Thiazide diuretics in an oedematous patient
    • Giving isotonic saline to a patient with SIADH

At the same time ADH must be present to prevent the excretion of EFW:

  • ADH release in response to physiologic stimuli
    • Low effective circulating volume:
      • ECF volume depletion
      • Blood loss
      • Hypoalbuminaemia
      • Low cardiac output
    • Excessive pain, nausea, vomiting, or anxiety
  • ADH release without a physiologic stimulus
    • CNS or lung lesions
    • Neoplasms and granulomas such as TB
    • Metabolic lesions e.g. acute intermittent porphyria
    • Administration of agents that stimulate ADH release e.g. DDAVP or oxytocin
    • Drugs that augment or stimulate ADH release e.g. morphine, antineoplastic agents
    • Drugs that promote the actions of ADH on the kidney by increasing cyclic AMP levels or its bioactivity

There are two aspects to management:

  1. Prevention

  2. Treatment