What is hypotonic hyponatremia?

What is hypotonic hyponatremia?

Hypoosmolar hyponatremia is a condition where hyponatremia associated with a low plasma osmolality. The term “hypotonic hyponatremia” is also sometimes used. When the plasma osmolarity is low, the extracellular fluid volume status may be in one of three states: low volume, normal volume, or high volume.

What causes hypotonic hyponatremia?

Hypotonic hyponatremia represents an excess of free water. This excess free water can be caused by two mechanisms: Increased free water intake: The patient drinks a large volume of free water (greater than 18 L/day or greater than 750 mL/h) that overwhelms kidney capacity to excrete free water.

What are the signs and symptoms of low sodium hyponatremia?

What are the symptoms of hyponatremia?

• Muscle cramps or weakness.
• Nausea and vomiting.
• Lethargy, or low energy.
• Headache and confusion.
• Mental status changes.
• Seizures.

What is hypotonic loss?

Patients who lose hypotonic fluid have a deficit in free water and electrolytes (low total body sodium and potassium) and have decreased extracellular volume. In these patients, hypovolemia may be more life threatening than hypertonicity.

What happens during hypotonic?

Hypotonic solutions have more water than a cell. Tapwater and pure water are hypotonic. A single animal cell ( like a red blood cell) placed in a hypotonic solution will fill up with water and then burst. This is why putting water on a bloodstained piece of clothing makes the stain worse.

What are the signs and symptoms of hypotonic hyponatremia?

There should be clinical signs of hypovolemia, such as sunken eyes, dry mouth, and so on. If the patient is edematous and the urinary [Na+] is low, then there is a problem with neuroendocrine handling of ECF volume.

How is osmolality reduced in hypotonic hyponatremia with volume contraction?

Hypotonic Hyponatremia. Serum osmolality is reduced in hypotonic hyponatremia (<280 mOsm/L). In cases of hypotonic hyponatremia with volume contraction, there is a disproportionally greater loss of sodium than of water.

What causes hyponatremia when you drink too much water?

In hyponatremia, one or more factors — ranging from an underlying medical condition to drinking too much water — cause the sodium in your body to become diluted. When this happens, your body’s water levels rise, and your cells begin to swell.

How is hyponatremia related to psychogenic polydipsia?

Another cause is psychogenic polydipsia. A third group of people with hyponatremia are often said to be “hypervolemic”. They are identified by the presence of peripheral edema. In fact, the term “hypervolemic” is misleading since their blood volume is actually low.