Sodium and Water Disorders

Low, High

Osmosis refers to the movement of solvent from ____ to ____ solute concentration

Mass

Osmolality describes the concentration of solute in a solvent in terms of ______ of solvent.

Volume

Osmolarity describes the concentration of solute in a solution in terms of _______ of solution.

Sodium

What is the primary effective osmole of the extracellular space?

135 - 145 mEq/L

What is the normal range for sodium?

Total body water

The measured sodium concentration is influenced by both total body water and the amount of sodium in the body. However, disturbances to serum concentrations of sodium are due to changes to ________

High

If a patient has depletion of total body water, this is represented as having ______ osmolality in the serum

Low

If a patient has water retention or not enough solutes, this is represented as having ______ osmolality

275-295 mOsm/Kg

What is the normal range for serum osmolality?

Tonicity

This term measures the osmotic pressure gradient between two solutions that are separated by a semi-permeable membrane

Isotonic

This term refers to having the same osmolality between the extracellular fluid and the intracellular fluid.

Hypertonic

This term refers to having a higher osmolality in the extracellular fluid compared to the intracellular fluid. Fluid volume will move towards the extracellular fluid.

Hypotonic

This term refers to having a lower osmolality in the extracellular fluid compared to the intracellular fluid. Fluid volume will move towards the intracellular fluid.

Hyponatremia

This condition is defined as having a serum sodium concentration that is less than 135 mEq/L.

Mild hyponatremia

What degree of hyponatremia occurs when serum sodium concentration is between 130-134 mEq/L?

Moderate hyponatremia

What degree of hyponatremia occurs when serum sodium concentration is between 125-129 mEq/L?

Severe hyponatremia

What degree of hyponatremia occurs when serum sodium concentration is less than 125 mEq/L?

Mild and Moderate

Which severity of hyponatremia presents with N/V, vomiting, weakness, headache, gait disturbances, and fatigue?

Severe

Which severity of hyponatremia presents with delirium, confusion, ataxia, seizures, and brain stem herniation?

Medications

Causes of hyponatremia include kidney disease, ______ such as SIADH and diuretics, diet, alcohol use disorder, and water intoxication.

SIADH

______ most commonly induces euvolemic hyponatremia

Diuretics

______ most commonly induces hypovolemic hyponatremia

Osmolality, sodium

Comprehensive metabolic panel, serum osmolality, and urine studies including _____ and _____ are needed for hyponatremia laboratory testing

Isotonic hyponatremia

This type of hyponatremia has normal serum osmolality where there is not a true sodium deficiency. Check for elevated lipids or proteins.

Hypertonic hyponatremia

This type of hyponatremia has a high osmolality (> 295 mOsm/kg) despite having low sodium. Check for unmeasured solutes.

Hypotonic hyponatremia

This type of hyponatrmia has low osmolality (< 280 mOsm/kg)

Hypertonic hyponatremia

This type of hyponatremia can be treated by removing or correcting the abnormal effective osmole concentration that is contributing to the hyponatremia.

Hyperglycemic

The equation for corrected sodium is only used in patients that are _______ because glucose is a type of effective osmole that contributes to serum tonicity and may cause low sodium concentrations due to the influx of water.

Volume status

Unlike hypernatremia, if a patient presents with hyponatremia, their _______ must be evaluated to determine the cause of the low sodium concentration.

Hypervolemia

If a patient presents with elevated volume, osmolality < 275 most/kg, Na < 135 mEq/L, most likely the patient has _______

Hypervolemic hypo-osmolar hyponatremia

Conditions that may lead to _________ include heart failure, CKD, and liver failure.

GDMT

What is the treatment for Heart Failure?

Dialysis

What is the treatment for CKD?

Diuretics

What is the treatment for Liver Failure?

Euvolemic hypotonic hyponatremia

SIADH is a condition that may cause _________ because excessive secretion of ADH or increased sensitivity to V2 receptors will cause an increase in fluid retention leading to the dilution of sodium levels in the serum.

ADH-Dependent Euvolemic Hypotonic Hyponatremia

Patients with adrenal insufficiency, hypothyroidism, and SIADH may develop _________.

ADH-Independent Euvolemic Hypotonic Hyponatremia

Patients with conditions that excrete excess water such as beer potomania, psychogenic polydipsia, and tea and toast diet, may develop _________.

Psychogenic Polydipsia

__________ is a condition where a patient takes in an excessive amount of water that suppresses ADH and can be a cause of euvolemic hypotonic hyponatremia.

High

Patients with ADH-dependent euvolemic hypotonic hyponatremia will have _____ levels of ADH, such as SIADH, will have urine sodium levels greater than 20 mEq/L.

Low

Patients with ADH-independent euvolemic hypotonic hyponatremia will have ______ levels of ADH, such as primary polydipsia, tea and toast diet, malnutrition or excessive alcohol intake, will have urine sodium levels less than 20 mEq/L.

Surgery

Causes of SIADH include head injuries, mechanical ventilation, pain, pneumonia, ______, tumors, and medications.

Stimulate the release of ADH

Medications that may ________ and induce SIADH include dopamine agonists, MDMA, nicotine, opioids, oxytocin, TCAs

Potentiate ADH

Medications that ______ and induce SIADH include desmopressin and NSAIDs

Mixed action

Medications that have ______ and induce SIADH include SSRIs, anticonvulsants, and antipsychotics

Captains

Treatment for SIADH include stopping medication, fluid restrictions, loop diuretics, and ______.

Skin turgor, mucous membranes

Patients with hypovolemic hypo-osmolar hyponatremia may present with decreased _____ and dry _______.

Hypovolemia

Nausea, vomiting, diarrhea are extrarenal cause of _______ leading to the loss of both sodium and water in the fluid.

Small Bowel Obstruction

GI loses, _________, and sweating are all non-renal causes of hypovolemic hypo-osmolar hyponatremia.

Cerebral Salt Wasting

Diuretic use and ________ are all renal causes of hypovolemic hypo-osmolar hyponatremia.

Hypovolemic, euvolemic

The use of diuretics may lead to either _______ or ________ hyponatremia

Non-renal

All hypovolemia patients will have concentrated urine due to increased water reabsorption in the kidneys, however, if patients have a urine sodium concentration that is less than 30 mEq/L, it will most likely indicate an ________ cause for the hypovolemia.

Renal

All hypovolemia patients will have concentrated urine due to increased water reabsorption in the kidneys, however, if patients have a urine sodium concentration that is greater than 30 mEq/L, it will most likely indicate a ______ cause for the hypovolemia.

Hypertonic saline (3%)

What type of saline fluids would be best used for a patient that has severe hyponatremia or SIADH?

Osmotic demyelination syndrome

When correcting a patient's hyponatremia, the serum sodium level should not be increased more than 12 mEq/L because it may induce _______, which is an irreversible condition where fluid shifts from the intracellular space to the extracellular space and results in damage and demyelination of neurons.

Osmotic demyelination, cerebral edema

The rapid correction of chronic hyponatremia or rapid onset of acute hypernatremia may lead to ________ and _______

154 mEq/L

What is the infusate sodium concentration for normal saline (0.9% NaCl)?

513 mEq/L

What is the infusate sodium concentration for hypertonic saline (3% NaCl)?

100 - 150 mL

One strategy to correct acute hyponatremia is by giving a bolus dose of hypertonic saline; _______ infused over 10 - 20 minutes.

4 hours

An option for rechecking is checking sodium every ______ after each bolus

5%, 12mEq/L

The initial goal of treating acute hyponatremia is to increase serum sodium by ________ to stabilize the patient with severe hyponatremia. However, the increase should not be more than 5 mEq/L in the first hour or else it increases the risk of overcorrection. The rest of treatment will occur more slowly to prevent overcorrection where the serum sodium will not increase by more than ______ per day

Slower, more

When treating a patient's acute hyponatremia, normal saline fluid may provide _______ serum sodium correction and _______ fluid volume. This type of fluid has less of a risk of overcorrection.

Faster, less

When treating a patient's acute hyponatremia, hypertonic saline fluid may provide _________ serum sodium correction and _______ fluid volume. This type of fluid can be used in patients that have volume overload or have severely low serum sodium.

Desmopressin

What drug administered IV or SC is used to prevent overcorrection?

Serum osmolality

(2 x Na) + (Glucose/18) + (BUN/2.8)

This is the equation for?

Corrected sodium

Measured Na + [(Glucose-100/100) x 1.6]

This is the equation for?

Sodium deficit

(Desired Na - Serum Na) x (Body weight in kg x 0.6)

This is the equation for?

Fluid volume

[(Na deficit x 1000)/ Infusate Na concentration]

This is the equation for?

Normal saline

What type of saline fluids when administered to a patient with SIADH will worsen their hyponatremia and cause serum sodium to decrease more?

Mild to moderate hypovolemic hyponatremia

The goal of treating ________ is by giving isotonic fluids, such as normal saline or lactated ringer, to restore effective circulating volume.

Fluid restriction of 1-1.2L per day

What is the first line therapy of treating euvolemic hypotonic hypovolemia?

15 - 30

The use of ______ grams of urea, fluid restriction, hypertonic saline, and vaptans are used for the treatment of euvolemic hypotonic hyponatremia.

Vasopressin receptor antagonist

Conivaptan is a nonselective _________ that can only be administered inpatient because it only comes as IV dosing. This medication is used for the treatment of euvolemic hypotonic hyponatremia, but patients should not be on fluid restriction as these medications cause excessive fluid excretion

3-4 days

What is the maximum duration of treatment of Conivaptan because of the risk of overcorrection and side effects?

V2 Vasopressin receptor antagonist

Tolvaptan is a selective ________ that comes in an oral dose. This medication is used to treat euvolemic hypotonic hyponatremia caused by SIADH, but patients should not be on fluid restriction as this medication can cause excessive water excretion

30 days

What is the maximum duration of therapy of Tolvaptan due to its hepatotoxicity risk?

Hepatotoxicty

What is the black box warning of Tolvaptan?

N/V

Side effects of Tolvaptan include dry mouth, increase thirst, and _____.

3-9

_____ g of sodium chloride tablets may be used to treat euvolemic hyponatremia.

1-1.2L per day

To treat hypervolemic hypotonic hyponatremia, the patient must be on a sodium restricted diet of 1000-2000 mg/day and fluid restriction of ___________, or diuresis/dialysis.

> 145 mEq/L

Hypernatremia is defined as sodium _______

Excessive urination

Hypernatremia may present with fatigue, weakness, lethargy, ________, and increased thirst

Increased sodium intake

Hypernatremia may be caused by increased free water loss, decreased free water intake, and _______.

Arginine vasopressin disorders

What is a major cause of increased free water loss in hypernatremia?

Tube feeds without flushes

_______ and decreased oral intake are causes of decreased free water intake in hypernatremia.

History of GI losses

Hypovolemic hypernatremia may be caused by ______, burns, and tube feeds. Urine electrolytes are needed to differentiate renal and non-renal causes

LR, D5W

To treat hypovolemic hypernatremia, use fluid resuscitation with ____ and free water with _____

Cerebral edema

When treating hypovolemic hypernatremia, do not correct water deficit by more than 12 mEq/L per day or else it will increase the risk of developing ________

Free water deficit

Total body weight x [1 - (140/Serum Na)]

This is the equation for?

Euvolemic hypernatremia

Diabetes insipidus is the primary cause of what type of hypernatremia?

Demeclocycline

Lithium, cisplatin, and _______ are medications that may induce euvolemic hypernatremia

Deficiency

AVP-D is a ______ of AVP, while AVP-R is a renal insensitivity to AVP

Central diabetes insipidus (AVP-D)

To determine which type of diabetes insipidus is causing a patient's euvolemic hypernatremia, Desmopressin is administered. If the Desmopressin causes a prompt increase in urine osmolality by 50%, it most likely indicates _________

Dilution hyponatremia

Side effects of desmopressin include ______ with the need to monitor serum sodium and urine osmoses

Nephrogenic diabetes insipidus (AVP-R)

To determine which type of diabetes insipidus is causing a patient's euvolemic hypernatremia, Desmopressin is administered. If the Desmopressin does not cause a prompt a change in urine osmoles, it most likely indicates _________

Desmopressin

When treating euvolemic hypernatremia in patients with AVP-D, the patient should be on fluid restriction and receive ______ to replace the lack of Vasopressin.

Thiazide Diuretics

To treat AVP-R, the patient should be on sodium and water restriction, ______ and hypotonic solution to replace any free water deficits.

Primary Hyperaldosteronism

Administration of hypertonic fluids as well as history of HTN and hypokalemia, which can cause concern for ______, are all causes of hypervolemic hypernatremia.

Excess sodium intake → D5W and Loop Diuretic

What is the primary treatment of hypervolemic hypernatremia?

Furosemide

Which loop diuretic is used for hypervolemic hypernatremia?