Differential Diagnosis for Low Sodium in a Healthy 67 YOF
- Single most likely diagnosis
- Dehydration or volume depletion: This is often the most common cause of low sodium levels, especially in the elderly, due to decreased thirst sensation, medications, or gastrointestinal losses.
- Other Likely diagnoses
- Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH): This condition can occur due to various reasons such as pulmonary diseases, neurological disorders, or certain medications, leading to excessive water retention and dilutional hyponatremia.
- Heart failure: Decreased cardiac output can lead to increased ADH secretion, causing water retention and hyponatremia.
- Liver cirrhosis: Cirrhosis can cause an imbalance in fluid and electrolytes, leading to hyponatremia due to increased ADH secretion and decreased renal function.
- Nephrotic syndrome: Excessive loss of protein in the urine can lead to hypoalbuminemia, causing a decrease in oncotic pressure and subsequent water retention, resulting in hyponatremia.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Adrenal insufficiency: This is a life-threatening condition that can cause hyponatremia due to decreased aldosterone production, leading to impaired renal function and electrolyte imbalance.
- Myxedema coma: Severe hypothyroidism can cause hyponatremia due to decreased cardiac output, increased ADH secretion, and impaired renal function.
- Diuretic-induced hyponatremia: Certain diuretics, especially thiazides, can cause hyponatremia due to excessive sodium loss and water retention.
- Rare diagnoses
- Cerebral salt wasting: A rare condition characterized by excessive renal sodium loss due to cerebral disease, leading to hyponatremia.
- Reset osmostat: A rare condition where the body's osmoregulatory mechanism is reset, causing hyponatremia due to excessive water intake or retention.
- Hypothyroidism: Although not as rare as other conditions in this category, hypothyroidism can cause hyponatremia due to decreased cardiac output, increased ADH secretion, and impaired renal function.