Sodium excess may be caused by inadequate fluids, excessive fluid losses, excessive administration of sodium, impaired renal function, and aldosteronism. Sodium excess may take two forms. The first form, known as hypernatraemia, is a rise in extracellular concentration which may be the consequence of too little available water or over-provision of sodium against a low excretion-rate. The second form is too much sodium and water in the body without change in the extracellular concentration. Retention of sodium leads to the accumulation of extracellular fluid (oedema), which may affect the cerebral, pulmonary, or peripheral circulations.
General adverse effects of excess sodium in the body include nausea, vomiting, diarrhea, abdominal cramps, thirst, reduced salivation and lachrymation, sweating, fever, tachycardia, hypertension, renal failure, peripheral and pulmonary oedema, respiratory arrest, headache, dizziness, restlessness, irritability, weakness, muscular twitching and rigidity, convulsions, coma and death. Poisoning from sodium chloride has resulted from unsuccessful induction of emesis, gastric lavage with hypertonic saline, and errors in the formulation of infant feeds. Excessive administration of sodium chloride causes hypernatraemia, the most serious effect of which is dehydration of internal organs, especially the brain. Excess chloride in the body may cause a loss of bicarbonate with an acidifying effect.
Intra-amniotic injection of hypertonic solutions or sodium chloride, which was formerly used for abortion induction, has been associated with serious adverse effects including disseminated intravascular coagulation, renal necrosis, cervical and uterine lesions, haemorrhage, pulmonary embolism, pneumonia, and death.
Treatment of Adverse Effects:
In the event of recent acute ingestion of sodium chloride, induction of emesis or gastric lavage should be carried out along with general symptomatic and supportive treatment.
In hypernatraemia serum-sodium concentrations should be corrected slowly at a rate not exceeding 10 to 12 mmol per litre daily: suggested fluids for administration intravenously have included both hypotonic and isotonic (which is hypotonic with respect to a hypertonic patient) sodium chloride solutions. It has also been suggested that dialysis may be necessary if there is significant renal impairment, the patient is moribund, or if the serum-sodium concentration is greater than 200 mmol per litre.