Hypernatremia is defined as an increased blood sodium levels > 145 mEq/L, that may happen in relation to water loss or sodium excess.
Sodium electrolyte is the major determinant of the extracellular fluid osmolality, meaning that hypernatremia causes hyperosmolality.
As we mentioned previously in fluid and electrolyte balance, osmolality refers to measurement of the concentration of molecules per weight of water (mOsm/Kg).
Hyperosmolality itself intiate a shift of water out of the cells, which leads to cellular dehydration.
Previously in in fluid and electrolyte article, we mentioned thirst mechanism in regulation water balance in the body, it's the first line protection against the hyperosmolality.
From what was mentioned, we can conclude that hypernatremia isn't considered a problem in alert individuals in access to water, can sense thirst (NB: thirst mechanism may be decreased in elderly), and is able to swallow.
Osmoreceptors in the hypothalamus sense a body fluid deficit or increase in plasma osmolality, which in turn stimulates thirst and ADH release from the hypothalamus, ADH is also stored in the pituatry gland at the base of brain.
Causes of hypernatremia
- Excessive Sodium intake:
- Intravenous fluids, such as hypertonic NaCl / sodium bicarbonate or even excessive isotonic NaCl.
- Hypertonic tube feedings without water supplements, due to the fact that osmotic diuresis can result from administration of concentrated hyperosmolar tube feedings.
- Near-drowning in salt water due to ingestion of seawater.
- Sodium-containing drugs, excessive oral intake of sodium.
- Inadequate Water Intake:
- Unconscious or cognitively impaired individuals, Hypernatremia secondary to water deficiency is usually due to impaired consciousness or an inability to drink liquids.
- Excessive Water Loss (high sodium concentration)
- Increased insensible water loss such as in heatstroke, prolonged hyperventilation or excessive sweating and increased sensible losses from high fever
Insensible water loss is the invisible vaporization from the lungs and skin, accounts for 600 to 900 mL/day loss.
- Osmotic diuretic therapy
Osmotic diuretics are agents that inhibit the reabsorption of solute and water by altering osmotic driving forces along the nephron. (Guignard, 2012).
- Diarrhea
- Disease States
- Diabetes insipidus, A deficiency in the synthesis or release of ADH from the posterior pituitary gland (central diabetes insipidus) or a decrease in kidney responsiveness to ADH (nephrogenic diabetes insipidus) can result in profound diuresis, thus producing a water deficit and hypernatremia.
- Primary hyperaldosteronism, (hypersecretion of aldosterone) caused by a tumor of the adrenal glands.
- Cushing syndrome
Cushing’s syndrome occurs when adrenal cortex secretes a lot of cortisol over a long period of time. Cortisol helps:Cushing’s syndrome can cause health problems such as
- maintain blood pressure
- regulate blood glucose, also called blood sugar
- reduce inflammation
- turn the food you eat into energy
- heart attack and blood clots
- infections
- bone loss and fractures
- high blood pressure, unhealthy cholesterol levels, insulin resistance and prediabetes and type 2 diabetes
- depression or other mood changes
- memory loss or trouble concentrating
- Uncontrolled diabetes mellitus, osmotic diuresis can result from hyperglycemia associated with uncontrolled diabetes mellitus. (NIDDK, 2018).
Clinical Manifestations
The manifestations of hypernatremia are primarily the result of water shifting out of cells into ECF causing cellular dehydration.
- Hypernatremia With Decreased ECF Volume
- Restlessness, agitation, twitching, seizures. coma, Dehydration of brain cells results in neurologic manifestations such as intense thirst, agitation, and decreased alertness, ranging from sleepiness to coma.
- Intense thirst. Dry, swollen tongue. Sticky mucous membranes
- weight loss
- Manifestations such as postural hypotension, weakness, and decreased skin turgor occur.
- Hypernatremia With Normal or Increased ECF Volume
- Restlessness, twitching, seizures. coma
- Intense thirst, flushed skin
- Weight gain. peripheral and pulmonary edema
- high blood and central venous pressures
Nursing care plan for hypernatremia: Assessment
- Assess skin turgor, vital signs mainly HR and BP.
- Monitor intake and output.
- Monitor weight daily.
- Physical examination and meticulous examination of signs and symptoms.
- Laboratory investigations:
- Serum electrolyte levels.
- ECG changes can also contribute to the diagnosis of fluid and electrolyte imbalance.
- ABG test to acid-base imbalances.
Nursing Care plan for hypernatremia: Nursing Diagnosis
- Risk for injury related to altered consciousness and seizures
- Risk for fluid volume deficit related to hypernatremia
- Risk for electrolyte imbalance related to excessive intake of sodium and/or loss of water
Nursing care plan for hypernatremia: patient's goal
- The patient will remain safe during therapy.
- The patient will maintain balanced fluid volume by the end of treatment.
- The patient will maintain balanced electrolyte by the end of treatment.
Nursing Care plan for hypernatremia: Nursing Management
- The primary goal of treatment of hypernatremia is to treat the underlying cause.
- In primary water deficit
- fluid replacement either orally or intravenously with isotonic or hypotonic fluids such as 5% dextrose in water or 0.45% sodium chloride saline solution.
- The goal of Nursing management for:
- sodium excess is to dilute the sodium concentration with sodium-free IV fluids, such as 5% dextrose in water, and to promote excretion of the excess sodium by administering diuretics.
- Monitor serum sodium levels and the patient’s response to therapy.
- Rapid reduce of serum sodium levels can cause a rapid shift of water back into the cells, resulting in cerebral edema and neurologic complications. People high risk for rapid water shift include patients with hypernatremia over several days or longer.
- Dietary sodium intake is often restricted.
Download our nursing care plan for fluid and electrolytes imbalance: hypernatremia from slideshare.
References:
- Feher, J. (2017). Osmosis and osmotic pressure. Quantitative Human Physiology, 182–198. https://doi.org/10.1016/b978-0-12-800883-6.00017-3
- Guignard, J.-P. (2012). Use of Diuretics in the newborn. Nephrology and Fluid/Electrolyte Physiology: Neonatology Questions and Controversies, 233–250. https://doi.org/10.1016/b978-1-4377-2658-9.00014-5
- Lewis, S. (2016). Medical surgical nursing: Assessment and management of clinical problems. Mosby.
- NIDDK. (2018, May). Cushing's syndrome. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/endocrine-diseases/cushings-syndrome.
