Sodium & Water Disorders - Darkow

hrmrmmrmrmm mayhaps salt to low?

Sodium is measured in

mEQ

Normal Na

135-145 mEq/L

Components of the ECF

Plasma & Interstitial Fluid

What maintains homeostasis between the ECF & ICF

Na+/K+/ATPase pump

Main components of ICF

K, Mg, P

Main components of the ECF

Na, Cl, HCO3-

Hyponatremia is

Na <135 mEq/L

T/F People with Hyponatremia are always symptomatic 

False

What is the concentration of Na where patients are generally at the most risk of Seizures, Brain damage, coma or death? 

<120 mEq/L

What is Central Pontine Myelinolysis

A condition where water moves too quickly from the ICF to ECF causing brain cells to rapidly shrink & hemorrhage

Can cause dysarthria, dysphagia, seizures and AMS - Worst case death

Effects occur with in 1-6 days are are Irreversible

Normal Serum Osmolality 

275-290 mOsm/kg 

Hypertonic Hypernatremia is usually caused by _________

Hyperglycemia 

Causes of Hypovolemic Hypotonic Hyponatremia

V/D, Sweating, Diuretics (Thiazides usually), Salt wasting

In Hypovolemic Hypotonic Hyponatremia, Both Sodium and water are being lost, but _____ loss is greater 

sodium

Treatment for Hypovolemic Hypotonic Hyponatremia without Neurological Symptoms

Isotonic Fluids like Isotonic Saline

Treatment for Hypovolemic Hypotonic Hyponatremia with Neurological Symptoms 

3% NaCl 

Hyponatremia Replacement therapy Goal

6-8 mEq/L/day

Maximum Sodium increase per day

12 mEq/L

Why is Hypertonic solutions safer in Acute Hyponatremia than in Chronic? 

The brain has not yet adapted to the tonicity, and when it has, rapid changes can kill or cause severe effects on a person 

Fluid Replacement rate for Acute Hypovolemic Hypotonic Hyponatremia

1 mEq/L/Hr

Fluid Replacement for Chronic Hypovolemic Hypotonic Hyponatremia

0.5 mEq/L/Hr

in Hypovolemic Hypotonic Hyponatremia:

Total Body water is _______
Total Body Sodium _______
Extracellular Fluid is ________
Edema is ______

Reduced 
Reduced
Reduced 
Absent 

In Hypervolemic Hypotonic Hyponatremia:

Total Body water is _______
Total Body Sodium _______
Extracellular Fluid is ________
Edema is ______

Increased
Increased
Greatly Increased
Present

Common Causes of Hypervolemic Hypotonic Hyponatremia

HF Exacerbation, Cirrhosis, Renal Disease, Pregnancy

Treatment for Acute/Severe Hypervolemic Hypotonic Hyponatremia

NaCl 3%

Treatment for Asymptomatic Hypervolemic Hypotonic Hyponatremia

• Treat underlying Cause

• Reduce Fluid & Sodium intake

• Loop Diuretics

• LAST RESORT - Vaptans

Vaptans 

Drug class that suppresses ADH 

NOT recommended for Hypovolemic Hypotonic Hyponatremia

Euvolemic Hypotonic Hyponatremia is diagnosed by ________

Exclusion 

Common causes for Euvolemic Hypotonic Hyponatremia

SIADH, Kidney Failure

Treatment for Euvolemic Hypotonic Hyponatremia

• 3% NaCl

• Look Diuretics

• Reduce Fluid intake

• Na Tablets

• LAST RESORTS: Demeclocycline or Vaptans

What is Hypernatremia

Na >145 mEq/L

Goal treatment for hypernatremia

Reduce Na by 10 mEq/L until normal 

T/F Hypernatremia should be treated with 0.9% Saline

False

Only ______ Hypernatremic patients should be treated with 0.9% Saline

Hemodynamically Unstable

Diabetes Insipidus

ADH is not working because of lack of secretion or lack of kidney response

Central DI

ADH is not secreted

Nephrogenic DI 

Kidney will not respond to ADH 

How to tell the difference between Central and Nephrogenic DI

Administer Desmopressin w/ Fluid restriction, Hypernatremia resolves/betters it is Central DI

How is Central DI treated

SQ Desmopressin titrated to appropriate dose

How is Nephrogenic DI treated?

Thiazide diuretics & Dietary Na restriction

Common DI Treatment Agents 

Desmopressin (Only Central), HCTZ, Indomethacin

Low Sodium and High Serum Osmolality is indicative of

Hypertonic Hyponatremia

Low Sodium, Low Serum Osmolality, and High Urine Osmolality is indicative of

Hypovolemic LHypotonic Hypernatremia

Low Sodium, Low Serum Osmolality, and Normal Urine Osmolality is indicative of

Hypervolemic Hypotonic Hyponatremia 

High Urine Osmolality

>450 mOsm/kg

Normal Urine Osmolality

>100 mOsm/kg

Low Sodium, Low Serum Osmolality, and Normal Urine Osmolality with ruled out HF, Cirrhosis and Nephrosis

Euvolemic Hypotonic Hypernatremia