Table 3.
Cause of hypernatremia
| 1. Net water loss |
|
|
| 1) Euvolemia (pure water loss = water deficit) |
| ↓↓total body water, total body Na+ unchanged |
|
|
| Extrarenal losses |
|
|
| Respiratory (tachycardia) |
|
|
| Dermal (sweating, fever) |
|
|
| Renal losses |
|
|
| Central diabetes insipidus (neurogenic) |
|
|
| Post-traumatic |
|
|
| Caused by tumors, cysts, histiocytosis, tuberculosis, sarcoidosis |
|
|
| Idiopathic |
|
|
| Caused by aneurysms, meningitis, encephalitis, Guillain-Barré syndrome |
|
|
| Caused by ethanol ingestion (transient) |
|
|
| Nephrogenic diabetes insipidus |
|
|
| Congenital |
|
|
| Acquired |
|
|
| Caused by renal disease (e.g., medullary cystic disease) |
|
|
| Caused by hypercalcemia or hypokalemia |
|
|
| Caused by drugs (lithium, demeclocycline, foscarnet, methoxyflurane, amphotericin B, vasopressin V2 receptor antagonists) |
|
|
| Other |
|
|
| Inability to gain access to fluids |
|
|
| Hypodipsia or adipsia |
|
|
| Reset osmostat (essential hypernatremia) |
|
|
| 2) Hypovolemia (hypotonic fluid loss = combined water and sodium deficit) |
| ↓↓total body water, ↓total body Na+ |
|
|
| Extrarenal losses |
|
|
| Gastrointestinal losses |
|
|
| Vomiting |
|
|
| Nasogastric drainage |
|
|
| Enterocutaneous fistula |
|
|
| Diarrhea |
|
|
| Use of osmotic cathartic agents (e.g., lactulose) |
|
|
| Dermal (cutaneous causes) |
|
|
| Burns |
|
|
| Excessive sweating |
|
|
| Renal losses |
|
|
| Osmotic diuresis (mannitol, glucose, urea) |
|
|
| Loop diuretics |
|
|
| Postobstructive diuresis |
|
|
| Polyuric phase of acute tubular necrosis |
|
|
| Intrinsic renal disease |
|
|
| Others |
|
|
| 2. Hypertonic sodium gain (hypervolemia) |
| variable total body water (↓/unchanged/↑), ↑↑total body Na+ |
|
|
| Hypertonic saline (e.g, 3% normal saline) or NaHCO3 administration |
|
|
| Infants or comatose patients receiving hypertonic feeding |
|
|
| Ingestion of sodium chloride |
|
|
| Ingestion of seawater |
|
|
| Sodium chloride-rich emetics |
|
|
| Hypertonic saline enemas |
|
|
| Intrauterine injection of hypertonic saline |
|
|
| Hypertonic sodium chloride infusion |
|
|
| Hypertonic dialysis |
|
|
| Primary hyperaldosteronism |
|
|
| Cushing’s syndrome |
|
|
| Mineralocorticoid excess |