Overview of the causes of hyponatraemia in primary care and guide to suggested action levels*
| Hyponatraemia: causes5,8 | |
|---|---|
| *Thresholds for referral should, however, be based principally on clinical state and rate of change. | |
| †Such as: antidepressants, e.g. tricyclics, selective serotonin reuptake inhibitors; antidiabetic drugs, e.g. chlorpropramide, metformin; antineoplastic agents, e.g. vinca alkaloids, cyclophosphamide, cisplatin; antipsychotic drugs, e.g. phenothiazines, butyrophenones; analgesics, e.g. non-steroidal anti-inflammatory drugs; antiepileptic drugs, e.g. carbamazepine, sodium valproate; diuretics, e.g. thiazides, amiloride; and other drugs, e.g. alpha interferon, ecstasy. | |
| Pseudohyponatraemia: hyperproteinaemia, hypertriglyceridaemia Osmotic shift: hyperglycaemia | |
| Hypovolaemia (with net sodium depletion) | Skin loss: sweating |
| Gut loss: vomiting, diarrhoea | |
| Renal loss: diuretics, Addison’s disease, hyperglycaemia | |
| Hypervolaemia (with net water retention) | Congestive cardiac failure |
| Cirrhosis with ascites | |
| Nephrotic syndrome or chronic kidney disease | |
| Clinical euvolaemia (due to water retention and sodium loss) | SIADH and related syndromes |
| Drugs† | |
| Malignancy; typically lung, upper gastrointestinal | |
| Hypothyroidism | |
| Chronic lung disease, infection, abscess | |
| Cerebral injury, stroke, infection | |