Anion Gap

Mind The Gap

1. Element Symbol | Percentage in
Body

Hydrogen

o
Carbon c
H
N

Nitrogen

Calcium Ci
Phosphorus

Magnesium Mg

Trace elements include boron (B), chromium (Cr),

cobalt (Co), copper (Cu), fluorine (F), iodine (1),

iron (Fe), manganese (Mn), molybdenum (Mo), less than 1.0
selenium (Se), silicon (Si), tin (Sn), vanadium (V),

and zine (Zn).

65.0
[| es

a 5

Potassium K 4
e | és |

2. Table 2-1 Principal Elements in the Human Body

Element (% of total body weight)

Significance

Oxygen, O (65)

Carbon, C (18.6)
Hydrogen, H (9.7)

Nitrogen, N (3.2)

Calcium, Ca (1.8)

Phosphorus, P (1.0)

A component of water and other
compounds; gaseous form is
essential for respiration

Found in all organic molecules

A component of water and most
other compounds in the body

Found in proteins, nucleic acids,
and other organic compounds

Found in bones and teeth; important
for membrane function, nerve
impulses, muscle contraction,

and blood clotting

Found in bones and teeth, nucleic
acids, and high-energy compounds

Potassium, K (0.4)

Important for proper membrane
function, nerve impulses, and muscle
contraction

3. “Tan 65.1 The major complex blomolecules of cells

Biomolecule

Protein

Deoxyribonucleic acid (DNA)
Ribonuclele acid (RNA)
Polysaccharide (glycogen)

Lipids

Building block (repeating unit)
Amino acids

Deoxyribonuclaotides
Ribonucleotides
Monosaccharides (glucose)

Fatty acids, glycerol

Major functions
Fundamental basis of structure and
function of cell (static and dynamic functions}.
Repository of hereditary information,
Essentially required for protein biosynthesis.

Storage form of energy lo meet short term
demands,

Storage form of energy to meet long term
demands, structural components of membranes,

4. FT

Body fluid vol in a healthy 70kg adult male

Compartment

Volume

Subdivisions

Intracellular fluid, ICF
(2/3 of TBW)

28 L

Extracellular fluid, ECF
1/3 of TBW

14L

10.5 L
(interstitial fluid)

BS EL
(Plasma)

Total body water (TBW):
60% of body weight

5. VOLUME OF BODY FLUIDS IN 70 kg MAN

| INTRA CELLUAR FLUID -
- | 28 LROUGHLY 2/3 OF TBW) -

PLASMA
. 4 L (ROUGHLY % OF ECF)

6. Electrolytes are

Chemically reactive in metabolism

— Major cations
« Nat, Kt, Ca?*, H*

— Major anions
- Cl, HCO,, PO,*

Cation: positive ion
Anion: negative ion

7. What is meant by
ELECTROLYTES?

baaa when dissolved in body fluids
charged ions & is able to carry an
electrical current conducting electricity.

* Tt can be:

= CATION - positively charged electrolyte
m ANION - negatively charged electrolyte
*No. Cations = No. Anions for homeostasis

*Commonly measured in milliequivalents /
liter (mEq/L)

8. gain of

Lo

Anion
(-)

loss of
e dl

A neutral atom becomes an ion either by losing an electron (cation) or
by gaining an electron (anion).

9. Comparison of Ca

‚Anton.

Human Body

Anion

Cation

Works as anti oxidant

Increases acid and free radical in
the body

Relieves fatigue

Increases lactic acid in cells and
muscles

Activates the cells, immune booster

Increases Peroxidation lipin

Balances body and mind, better
sleep quality

Autonomic nerves imbalance,
insomia

Balance internal secretion system

Hormones imbalance

Purifies the blood, better circulation
Ube ae

Blood becomes thicker, affecting
circulation

aging

Accelerates aging

10. COMPOSITION OF BODY FLUIDS

“CATIONS (mmol) | Plasma Interstitial | Intracellular
Na 142 139 14
K 4.2 4.0 140
Ca 153 1.2 0
Mg 0.8 0.7 20
pANIONS-(mmol/D-|
cl 108 108 4.0
HCO3 24.0 28.3 1. |
Protein 1.2 0.2 4.0
HPO4 2.0 2.0 11

11. Extracellular and Intracellular Fluids

* Each fluid compartment of the body has a
distinctive pattern of electrolytes
+ Extracellular fluids are similar (except for the
high protein content of plasma)
— Sodium is the chief cation
— Chloride is the major anion
> Intracellular fluids have low sodium and
chloride
— Potassium is the chief cation
— Phosphate is the chief anion

12. TE EEE
Electrolytes & Body Fluids

= Major Cations: Sodium, Potassium,
Calcium, Magnesium.

a Major Anions: Chloride, Bicarbonate,
Phosphate.

= Intracellular Fluid: K* is the most
abundant cation, while HPO,? is the most
abundant anion.

= Extracellular Fluid: Na* is the most
abundant cation, while Cl is the most
abundant anion.

13. the major electrolytes are in body fluids are sodium,

potassium, chloride, bicarbonate, sulfate, magnesium
and calcium.

When dissociate form ions particles carrying a

positive (cation) or negative (anion) electric charges

— Cations — carrying a positive electric charge
. Nat, Kr , Ca, Ht

— Anions — carrying negative electric charge
«Cl, HCO, , PO,

Non-electrolytes - Uncharged
+ Proteins, urea, glucose, O,, CO,

14. Problems os

Deficient fluid volume

* Hypovolemia
e Dehydration
JExcess fluid volume
© Hypervolemia
© Water intoxication
® Electrolyte imbalance
® Deficit or excess of one or more electrolytes

® Acid-base imbalance

15. ~ ACI

Acid-base balance means regulation of [H-] in the body fluid.
Only slightly changes in [H-] fromthe normal value can cause marked
alteration in the rates of chemical reactions in the cell.
For this reason the regulation of [H*] is one of the most important aspects
of homeostasis.
2
pH = log ----—-----= - log [H-]
[Hr]
Forthe bicarbonate buffer system the formula may be expressed as Follow:
[HCO, ] in mmol/l
pH = 6.1 + log -—------------—-----—----—---
[CO,] in mmol/L
This is called the Henderson— Hasselbalch equation and by using it
one can calculate the pH of a solution.
* Acidosis ¿low pH-high [H-]
* Alkalosis :highpH-low [H-]

16. Inverse Relationship between the
Partial Pressure of Carbon Dioxide (Pco,) and Plasma pH

Homeostasis

4

Acidosis
H,0+CO,— H,CO,— H*+HCO,-

y

1

Alkalosis
H*+HCO,— H,CO,— H,0+CO,

17. MIND THE GAP

y

18. Anion Gap -——=

Cation-anion difference
Relationship among body cations
(+) & anions (-)

Helpful in dx & treating acidotic
conditions

Increases in gap = too much acid
in blood (acidosis) due to

= i.e. DKA, Lactic acidosis

19. Anion Gap

© Body water compartments exist in a state of
electroneutrality (anions=cations)
® Routine measurements: Na, K, Cl & HCO; levels

2 Anion Gap is the difference between unmeasured

anions and unmeasured cations.
© Formula: AG=(Na + K)- (Cl + HCO,)

The "real" balance is given by the equation:

[Na]+ [K] + [other cations] = [Cl] + [HCO3] + [other anions]
(INa]+ [K]) - (Cl + [HCO3])= [other anions] - [other cations

"Anion Gap“

20. Assessment Guidelines

<0.4
Hyperchloremic normal anion gap acidosis
<1 High AG & normal AG acidosis
1to2 Pure Anion Gap Acidosis

Lactic acidosis: average value 1.6
DKA more likely to have a ratio closer to 1 due to urine ketone loss

>2

High AG acidosis and a concurrent metabolic alkalosis

or a pre-existing compensated respiratory acidosis

21. Normal Anion Gap

Metabolic Acidosis

Loss of Bicarbonate:

Mineral Acid Load:

Diarrhea HCI > CE + H°
| va UA UA UA
HCO, Hco; HCO, HCO;
Nat — | Ne Nar > | ¡Na*
Sk cr cr cr

Diarrheal fluid

(©) 2007, Bertrand L. Jaber, MD

22. Increased Anion Gap
Metabolic Acidosis

lactic acidosis: Ketoacidosis:
LH >L +H: BHBH > BHB- + H*
AAH > AA +H*
UA UA UA U
Es SHB
HCO, HCO; AA-
HCO, NES
Nar > | Ne Na —-| na
cr cr cr cr
Increased Unmeasured Anions Increased Unmeasured Anions

(c) 2007. Bertrand L. Jaber, MD

23. Mormal Anion Gap Metabolic Acidosis

Diarrhea

Renal tubular acidosis

Adrenal insufficiency

Chronic kidney disease

Intestinal, pancreatic, biliary fistula
Hypoaldosteronism

Spironolactone, prostaglandin inhibitors,

triamterene, amiloride, trimethoprim,
pentamidine, cyclosporin

24. Causes of high anion-gap metabolic acidosis
CAT MUDPILES
|

Salicylates/ASA/Aspirin

* Ethanol (due to lactic acidosis)
* Ethylene glycol
Lactic acidosis
* Iron
* Isoniazid
* Inborn errors
of metabolism
* Paracetamol/Acetaminophen
* Phenformin
+ Paraldehyde

* Diabetic ketoacidosis

* Alcoholic ketoacidosis
* Starvation ketoacidosis

Uremia
Methanol

* Teophylline

+ Toluene (Glue-sniffing)
Aminoglycosides

# Carbon monoxide

* Cyanide

* Congenital

heart failure

25. Lithium Isopropanolol Methanol
Glycine Ethylene glycol
Mannitol Propylene glycol
Toluene Ethanol

Pseudohyponatremia | Lactic acidosis

Hypertriglyceridemia