Hypernatremia resident survival guide

Hypernatremia Resident Survival Guide
Overview
Causes
FIRE
Diagnosis
Treatment
Do's
Don'ts

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Mounika Lakhmalla, MBBS[2]

Overview

Hypernatremia is an electrolyte disturbance consisting of an elevated sodium level in the blood. It is defined as a serum sodium concentration exceeding 145 mEq/L. This is a relatively common problem particularly among young children, older adults, and hospitalized/critically ill who depend upon others to control their water intake.

Causes

Life Threatening Causes

Conditions that may cause death or permanent disability within the next 24 hours

Common Causes

The most common cause of hypernatremia is not an excess of sodium, but a relative deficit of free water in the body. Hypernatremia can be caused by many disease processes and drugs.

• Free water loss in form of diarrhea, diabetes insipidus, osmotic diuresis due to glycosuria , urea, and osmotic or loop diuretics, upper Gastrointestinal losses, insensible losses.

• Primary sodium excess is a rare cause of hypernatremia and can be due to massive salt ingestion or minaralocorticoid excess and administration of hypertonic sodium-containing solutions.

• Hypernatremia can also occur in cases of primary hypothalamic disease due to impaired thirst (hypodipsia) with or without concurrent diabetes insipidus.

Diagnosis

Shown below is an algorithm summarizing the diagnosis of [[disease name]] according the the [...] guidelines.

Treatment

Serum sodium > 145

Urine output

Low < 200

High

High urine osmolality

Urine osmolality

Hypotonic fluid loss GI losses nausea, vomiting, renal losses, diuretics

Low

High

Calculate free water deficit (see below) Replace both free water deficit and correct Ongoing Fluid losses as well Rate of correction no more than 1mEq/L/h Replace 1/2 fluid in 24 hrs, other 1/2 in 24-48 hrs Hypotension - Normal saline, Stable D5W

Negative water deprivation test

Osmotic diuresis

Diabetes insipidus

DDAVP

Increased urine osmolality

urine osmolality unchanged

Central Diabetes Insipidus

Nephrogenic diabetes Insipidus

Treat with Desmopressin &..

Treat with Thiazide diuretics, Acetazolamide &...

Do's

Don'ts

References