Section II: Disorders of Water and Sodium Metabolism

Section II: Disorders of Section II: Disorders of Water and Sodium Water and Sodium

MetabolismMetabolism

一、一、 ClassificationClassification

According to the changes of volume:According to the changes of volume: 1. Dehydration 1. Dehydration

2. Overhydration2. Overhydration

According to the changes of [NaAccording to the changes of [Na++]e:]e: 1. Hypernatremia1. Hypernatremia

2. Hyponatremia2. Hyponatremia

3.Normonatremia with changes of 3.Normonatremia with changes of volumevolume

According to the clinic According to the clinic importance:importance:(1) Dehydration(1) Dehydration1) Hypertonic dehydration 1) Hypertonic dehydration 2) Hypotonic dehydration 2) Hypotonic dehydration 3) Isotonic dehydration3) Isotonic dehydration

(2) Overhydration(2) Overhydration1) Hypertonic overhydration 1) Hypertonic overhydration 2) Hypotonic overhydration (Water 2) Hypotonic overhydration (Water

intoxication)intoxication)3) Isotonic overhydration (Edema)3) Isotonic overhydration (Edema)

二、二、 DehydratioDehydrationn

DehydrationDehydration 脱水脱水 (Hypovolemia(Hypovolemia))

Concept: The volume of body fluid Concept: The volume of body fluid decreases below the normal range after the decreases below the normal range after the loss of body fluid.loss of body fluid.

In dehydration the [NaIn dehydration the [Na++]e may be in three ]e may be in three manifestations:manifestations:

--------------------------------------------------------------- --------------------------------------------------------------- Dehydration [NaDehydration [Na++] Osmotic pressure] Osmotic pressure (mmol/L) (mOsm/L)(mmol/L) (mOsm/L)------------------------------------------------------------------------------------------------------------------------------Hypertonic >150 > 310 Hypertonic >150 > 310 Hypotonic <130 < 280Hypotonic <130 < 280Isotonic 130~150 280~ 310Isotonic 130~150 280~ 310----------------------------------------------------------------------------------------------------------------------------

1 Hypertonic Dehydration1 Hypertonic Dehydration

(1) Concept(1) Concept

(2) Causes(2) Causes

(3) Adaptive (compensatory) (3) Adaptive (compensatory) responses of theresponses of the

bodybody

(4) Characteristic effects(4) Characteristic effects

(5) Principle of treatment(5) Principle of treatment

1 Hypertonic Dehydration1 Hypertonic Dehydration


Both water and sodium are Both water and sodium are lost lost (hypovolemia),(hypovolemia), but the water but the water loss is in excess of salt loss.loss is in excess of salt loss.

Then the volume of ECF is Then the volume of ECF is reduced, reduced,

the [Nathe [Na++] is over 150 mmol/L, ] is over 150 mmol/L,

the plasma osmotic pressure is over the plasma osmotic pressure is over 310 mOsm/L. 310 mOsm/L.


1)1) Decreased water intakeDecreased water intake can be seen can be seen in: in:

①① No water during navigation or in desert. No water during navigation or in desert.

②② No sense of thirst due to brain injury or No sense of thirst due to brain injury or coma,coma,

③ ③ Severe vomitingSevere vomiting

④ ④ Difficulty in swallowing because of Difficulty in swallowing because of esophageal diseases.esophageal diseases.

⑤ ⑤ Underdose of infusion in treatment of Underdose of infusion in treatment of patientspatients

At the same time, pure water At the same time, pure water loss from lung (300ml/d) and skin loss from lung (300ml/d) and skin (500ml/d) is not avoidable, even (500ml/d) is not avoidable, even increased.increased.

2) Increased loss of 2) Increased loss of waterwater

①①via skinvia skin

②②via respirationvia respiration

③③via gastrointestinal tractvia gastrointestinal tract

④④via kidney,via kidney,

gains (ml/day) loss (ml/day)------------------------------------------drink 1200 lung 300food 1000 skin 500metabolic feces 200water 300 urine 1500------------------------------------------total 2500 2500

①① via skin: via skin:

Normally 500 ml of pure water will be lost Normally 500 ml of pure water will be lost by insensible evaporation from skin each day. by insensible evaporation from skin each day.

When the environmental or body When the environmental or body temperature is increased, the evaporation temperature is increased, the evaporation (insensible loss) will increase from skin.(insensible loss) will increase from skin.

Elevation of 1℃Elevation of 1℃(celsius)(celsius) will increase loss of will increase loss of 500 ml pure water by evaporation each day.500 ml pure water by evaporation each day.

Since sweat is hypotonic (0.2%NaCI), Since sweat is hypotonic (0.2%NaCI), there will be more water loss than salt loss there will be more water loss than salt loss during sweating.during sweating.

If water replenish is not enough.If water replenish is not enough.

②② via respiration:via respiration:

Since the expired air contains Since the expired air contains water vapour, the water loss from water vapour, the water loss from lung is 300 ml of pure water each lung is 300 ml of pure water each day. day.

The pure water loss is The pure water loss is increased to 1300ml/day. during increased to 1300ml/day. during hyperventilation.hyperventilation.

(metabolic acidosis, bronchitis, fever)(metabolic acidosis, bronchitis, fever)


③③ via gastrointestinal via gastrointestinal tracttract Vomiting and diarrhea will lose a lot Vomiting and diarrhea will lose a lot

of body fluid. of body fluid.

Gastric juice is isotonic, loss of Gastric juice is isotonic, loss of gastric juice with the loss of pure water gastric juice with the loss of pure water from skin and lung may lead to hypertonic from skin and lung may lead to hypertonic dehydration.dehydration.

The [NaThe [Na++] of] of watery stool is about watery stool is about 60 mmol/L (hypotonic fluid).60 mmol/L (hypotonic fluid).


④④ via kidney:via kidney:

When the ADH secretion is reduced, such When the ADH secretion is reduced, such as diabetes insipidus. Increased water loss as diabetes insipidus. Increased water loss occurs.occurs.

Patients with diabetes also have increased Patients with diabetes also have increased urinary water loss due to the urinary water loss due to the osmotic diuresis.osmotic diuresis.

Tube feeding with a high concentration of Tube feeding with a high concentration of protein is used to unconscious (coma) patients. protein is used to unconscious (coma) patients.

The urea will increase in the urine, which The urea will increase in the urine, which causes causes osmotic diuresis.osmotic diuresis.


(3) Adaptive (compensatory) (3) Adaptive (compensatory) responses of the bodyresponses of the body1) Drink more water because of severe 1) Drink more water because of severe

thirst thirst Hyperosmolarity and hypovolemia Hyperosmolarity and hypovolemia

stimulate the sense of thirst. stimulate the sense of thirst. Diminished saliva and the dry mucous Diminished saliva and the dry mucous

membranes lead to the sense of thirst. membranes lead to the sense of thirst. Obvious thirst occurs at early stage of Obvious thirst occurs at early stage of

hypertonic dehydration.hypertonic dehydration. If possible, the If possible, the patient may drink water until the patient patient may drink water until the patient has again normal osmolarity and normal has again normal osmolarity and normal volume of ECF.volume of ECF.

no thirstno thirst

increase of ECF osmolality (1~2%)

hypovolemia elevated angiotensin II vasoconcentration

dryness ofmouth

osmoreceptor (anterior hypothalamus

)

volume receptorin venae cavae and atrium

thirst center (anterior hypothalamus)

sense of thirst and drink of water

decrease of ECF

osmolality increase of ECF volume

decrease of angiotensin concentration II

disappear of dryness of mouth

2) Increased water 2) Increased water reabsorptionreabsorption by increased ADH by increased ADH

ADH release is stimulated ADH release is stimulated by the hyperosmolarity of the ECF by the hyperosmolarity of the ECF and the hypovolemia.and the hypovolemia.

ADH increases the ADH increases the reabsorption of water in kidneys. reabsorption of water in kidneys. The volume of ECF will increase. The volume of ECF will increase. The high osmolarity will decrease to The high osmolarity will decrease to normal.normal.

increase of ECF osmolality (1~2%) via osmoreceptor

hypovolemia via volume receptor

synthesis and release of ADH

decrease osmolality of ECF

increase volume of ECF

increases the reabsorption of water increases the reabsorption of water in kidneysin kidneys

3)Shift of water 3)Shift of water

ECF ICF

Increase of blood volume by shift of water from intracellular space.

(4) Characteristic effects of (4) Characteristic effects of hypertonichypertonic dehydration on the body dehydration on the body 1)1) ThirstThirst occurs at the early stage of occurs at the early stage of

hypertonic dehydration. hypertonic dehydration. 2) 2) Oliguria Oliguria occurs at the early stage of occurs at the early stage of

hypertonic dehydration. (<400~500 hypertonic dehydration. (<400~500 ml/day). ml/day).

Metabolic wastes like urea andMetabolic wastes like urea and uric uric acidacid are retained in the body because of the are retained in the body because of the oliguria. oliguria.

Urea andUrea and uric aciduric acid are harmful to the are harmful to the body. (azotemia)body. (azotemia)

Urine specific gravity is increased. Urine specific gravity is increased. NaNa++ in urine??? in urine???

renal blood flow

[Na+] in macula densa

excitement of sympathetic nerve

renin release from the juxtaglomerular cells

increase of angiotensin II releases

[K+], [Na+] blood flow in plasma

aldosterone secretion from adrenal cortex

Na+ reaborption in renal tubules

K + and H + excretion from kidneys

3) 3) FeverFever

Fever may be present because Fever may be present because water is necessary to regulate the water is necessary to regulate the body temperature.body temperature.

Fever is more severe in infants Fever is more severe in infants because of the dysfunction of because of the dysfunction of thermoregulatory center, which is thermoregulatory center, which is called called infantile dehydration feverinfantile dehydration fever..

4) 4) Intracellular dehydrationIntracellular dehydration

Water will Water will shift from ICF to shift from ICF to ECF because the ECF because the ECF is hypertonic. ECF is hypertonic. All the cells will All the cells will shrink.shrink.

Brain cell dehydration produces brain Brain cell dehydration produces brain dysfunction like lethargy dysfunction like lethargy (weakness, apathy, absence (weakness, apathy, absence

of interest),of interest), which may progresses to coma which may progresses to coma (unconsiousness)(unconsiousness) when the water deficient is when the water deficient is severe. severe.

Increased irritability Increased irritability (muscular twitch, delirium)(muscular twitch, delirium) may occur, especially in children.may occur, especially in children.

Twitch: uncontrollable sudden, quick movement of muscleTwitch: uncontrollable sudden, quick movement of muscle Delirium: violent mental disturbance accompanied by wild talk Delirium: violent mental disturbance accompanied by wild talk

(wild excitement)(wild excitement)

Subarachnoid hemorrhageSubarachnoid hemorrhage

5) loss of body weight5) loss of body weight

Loss of body weight occurs within Loss of body weight occurs within short period of time, which is useful in short period of time, which is useful in diagnosis of severity of dehydration.diagnosis of severity of dehydration.

6) blood concentration6) blood concentration (hemoconcentration)(hemoconcentration)

Count of WBC ↑Count of WBC ↑

Count of RBC ↑Count of RBC ↑

Hb (hemoglobin) ↑(in total blood, RBC) Hb (hemoglobin) ↑(in total blood, RBC)

Hematocrit ↑(percentage of RBC in total Hematocrit ↑(percentage of RBC in total blood)blood)

use in diagnosis?use in diagnosis?


1) Treat the primary disease, such as 1) Treat the primary disease, such as diarrhea.diarrhea.

2) Replace firstly with 5% glucose 2) Replace firstly with 5% glucose solution to reduce the solution to reduce the hyperosmolarity and to increase the hyperosmolarity and to increase the volume of ECF.volume of ECF.

3) Add small amount of 0.9% NaCl 3) Add small amount of 0.9% NaCl after infusion of 5% glucose solution. after infusion of 5% glucose solution.

4) How to decide the volume of 4) How to decide the volume of fluid replacement?fluid replacement?

----------------------------------------------------------------------------------------------------------------------------------------------------------------Degree Volume of water loss clinic manifestationDegree Volume of water loss clinic manifestation (% of body weight)(% of body weight)-------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Mild 2~5% thirst, oliguriaMild 2~5% thirst, oliguria

Moderate 5~10% severe thirstModerate 5~10% severe thirst fever fever dryness of mucosadryness of mucosa

Severe 10~15% delirium, stupor,Severe 10~15% delirium, stupor, comacoma--------------------------------------------------------------------------------------------------------------------------------------------------------------

3 . Hypotonic Dehydration3 . Hypotonic Dehydration


There is loss of both water There is loss of both water and sodium and sodium (hypovolemia),(hypovolemia), the Nathe Na++ loss loss is in excess of water lossis in excess of water loss, ,

The ECF is hypotonic The ECF is hypotonic ([Na([Na++]<130 mmol/L), the osmolarity ]<130 mmol/L), the osmolarity is lower than 280mOsm/L.is lower than 280mOsm/L.


1) Replace of water only1) Replace of water only to to the patients with dehydration the patients with dehydration caused by caused by vomiting, diarrhea, gastric vomiting, diarrhea, gastric suction and excessive sweating lost. suction and excessive sweating lost.

2) Adrenocortical insufficiency 2) Adrenocortical insufficiency (Addison’s disease) can cause excessive (Addison’s disease) can cause excessive renal loss of sodium because the renal loss of sodium because the secretion of aldosterone is reduced.secretion of aldosterone is reduced.

3) Some diuretics (e.g. Furosemide3) Some diuretics (e.g. Furosemide速尿速尿 ) ) inhibit the Nainhibit the Na++ reabsorption in reabsorption in renal tubules.renal tubules.

(3) Adaptive responses(3) Adaptive responses

Aldosterone secretion is Aldosterone secretion is stimulated by the low sodium stimulated by the low sodium concentration, except in the case of concentration, except in the case of adrenocortical insufficiencyadrenocortical insufficiency..

(4) Characteristic effect of (4) Characteristic effect of hypotonic dehydration on the hypotonic dehydration on the

bodybody1) Urine volume1) Urine volume Urine volume is variable (low, normal, Urine volume is variable (low, normal,

high) depending on the ADH secretion.high) depending on the ADH secretion. At the early stageAt the early stage of hypotonic of hypotonic

dehydration, decreased osmolarity is the dehydration, decreased osmolarity is the superior change, which inhibits ADH superior change, which inhibits ADH secretion, the urine is increased.secretion, the urine is increased.

At the late stage,At the late stage, severe hypovolemia severe hypovolemia is the superior change, which increase the is the superior change, which increase the ADH release . the urine volume is ADH release . the urine volume is decreased.decreased.

2) 2) Water shifts into Water shifts into the cells from the cells from ECF.ECF.

Severe hypovolemiaSevere hypovolemia

(Compare with hypertonic (Compare with hypertonic dehydration.)dehydration.)

ICFECF

3) Hypotension 3) Hypotension

The blood pressure may The blood pressure may decrease. Postural hypotension and decrease. Postural hypotension and shock will occur because the shock will occur because the decreased blood volume. decreased blood volume. (increased (increased urine and water shifts into the cells)urine and water shifts into the cells)

44) Severely reduced ) Severely reduced interstitial fluidinterstitial fluid

Low protein Low protein concentration and concentration and colloid osmotic pressure colloid osmotic pressure in interstitial space.in interstitial space.

The reduce of skin The reduce of skin elasticityelasticity

Eyeball tension is Eyeball tension is decreased, the eyeballs decreased, the eyeballs are soft and sunken.are soft and sunken.

5) Intracellular 5) Intracellular overhydrationoverhydration

Water will shift from Water will shift from ECF to ICF because the ICF ECF to ICF because the ICF is relatively hypertonic. The is relatively hypertonic. The cell will swell. cell will swell.

Brain cell Brain cell overhydration produces overhydration produces brain dysfunction. (Cranial brain dysfunction. (Cranial cavity is fixed)cavity is fixed)

(severe headache, high brain (severe headache, high brain pressure)pressure)

5) There is no obvious thirst at early 5) There is no obvious thirst at early stage because of the low crystal stage because of the low crystal osmotic pressure.osmotic pressure.

6) Blood concentration6) Blood concentration

Counts of WBC and RBC ?Counts of WBC and RBC ?

Hematocrit ?Hematocrit ?

Plasma protein concentration ?Plasma protein concentration ?

Hb in plasma ?Hb in plasma ?

Hb concentration in RBC ?Hb concentration in RBC ?

(5) Principles of treatment(5) Principles of treatment

Replacement of isotonic saline Replacement of isotonic saline (0.9%NaCl) .(0.9%NaCl) .

Replacement of hypertonic fluid Replacement of hypertonic fluid may lead to hypertonic state.may lead to hypertonic state.

Pure water is easy to loss via Pure water is easy to loss via skin and lung.skin and lung.

Hyperosmotic fluid are seldom Hyperosmotic fluid are seldom used, except in urgent state of brain used, except in urgent state of brain edema. edema.

4. Isotonic Dehydration4. Isotonic Dehydration

((1) Concept1) Concept There is loss of fluid There is loss of fluid

(dehydration), the water loss is (dehydration), the water loss is equal to salt loss. The ECF in the equal to salt loss. The ECF in the body is isotonic, body is isotonic,

the [Nathe [Na++] is 130~150 mmol/L, ] is 130~150 mmol/L, the osmolarity is 280~310 the osmolarity is 280~310

mOsm/L.mOsm/L.


1) Loss of fluid is caused by 1) Loss of fluid is caused by vomiting, diarrhea, hemorrhage and vomiting, diarrhea, hemorrhage and from the burned area. from the burned area.

2) The isotonic dehydration can be 2) The isotonic dehydration can be induced from hypertonic and induced from hypertonic and hypotonic dehydration by the renal hypotonic dehydration by the renal regulation.regulation.

(3) Adaptive responses(3) Adaptive responses

The main change in isotonic dehydration is The main change in isotonic dehydration is the reduced volume of ECF.the reduced volume of ECF.

1) It stimulates the thirst, so that the 1) It stimulates the thirst, so that the patient will ask to drink water to replace the patient will ask to drink water to replace the volume of ECF. volume of ECF. (not as strong as hypertonic (not as strong as hypertonic dehydration)dehydration)

2) ADH release is stimulated, so that the 2) ADH release is stimulated, so that the water reabsorption will increase to replace the water reabsorption will increase to replace the volume of ECF.(volume of ECF.(not as much as hypertonic not as much as hypertonic dehydration)dehydration)

3) Secretion of aldosterone is increased 3) Secretion of aldosterone is increased due to hypovolemia.due to hypovolemia.(not as much as hypotonic (not as much as hypotonic dehydration)dehydration)

(4) Effect on the body(4) Effect on the body 1) Urine volume is diminished 1) Urine volume is diminished

because of the decreased because of the decreased GFR, increased ADH and GFR, increased ADH and aldosterone secretion.aldosterone secretion.

2)Thirst2)Thirst 3) Poor skin3) Poor skin elasticityelasticity and and

sunken eyeball, because of the sunken eyeball, because of the reduction of interstitial fluid.reduction of interstitial fluid.

4) No water shift and related 4) No water shift and related symptoms and signs.symptoms and signs.

Turn into hypertonic Turn into hypertonic dehydration ( loss pure water) or dehydration ( loss pure water) or

to hypotonic dehydration to hypotonic dehydration (replacement of water only).(replacement of water only).


Hypotonic saline is needed to Hypotonic saline is needed to replace the fluid deficiency.replace the fluid deficiency.

Isotonic NaCl first.Isotonic NaCl first.

Case Discussion No.1Case Discussion No.1 A 36-year-old man was hospitalized A 36-year-old man was hospitalized

with a 3-day history of fever and watery with a 3-day history of fever and watery diarrhea. His blood pressure was 90/60 diarrhea. His blood pressure was 90/60 mmHg, the pulse was 112/min, temperature mmHg, the pulse was 112/min, temperature is 38.0℃. The abdomen was distended with is 38.0℃. The abdomen was distended with low skin elasticity. low skin elasticity.

The laboratory results were:The laboratory results were: Arterial blood: Arterial blood: pH=7.21, PaCOpH=7.21, PaCO22=26 mmHg=26 mmHg PaOPaO22= 108 mmHg. [Na= 108 mmHg. [Na++]=135 mmol/L]=135 mmol/L [K[K++] =3.0 mmol/L [HCO] =3.0 mmol/L [HCO33--] = 16 mmol/L] = 16 mmol/L Urine: pH=5.0, Specific gravity= Urine: pH=5.0, Specific gravity=

1.0281.028

The patient’s problems were:The patient’s problems were: (1)isotonic dehydration(1)isotonic dehydration (2)metabolic acidosis(2)metabolic acidosis (3)hypokalemia.(3)hypokalemia.

2. 2. 病例分析病例分析患婴，患婴， 33 个月，入院前个月，入院前 11 天开始发热。呕天开始发热。呕

吐，水样便每日吐，水样便每日 2020 余次。伴烦躁、烦渴。余次。伴烦躁、烦渴。查体：查体： 39.8℃, 39.8℃, 嗜睡，醒后烦躁，皮肤干嗜睡，醒后烦躁，皮肤干热，明显腹胀。治疗：抗菌素，输入生理热，明显腹胀。治疗：抗菌素，输入生理盐水盐水 1200ml1200ml 。次日病情加重，极烦渴，。次日病情加重，极烦渴，呼吸深，惊厥，昏迷，并发肠麻痹死亡。呼吸深，惊厥，昏迷，并发肠麻痹死亡。

三、三、 OverhydrationOverhydration

According to the [Na+] concentration:

(1)Hypertonic overhydration

(2) Hypotonic overhydration

(Water intoxication)Water intoxication)

(3) Isotonic overhydration

(Edema)(Edema)

1. Water intoxication1. Water intoxication


Excessive fluid in the body is Excessive fluid in the body is called overhydration.called overhydration.

Excessive hypotonic fluid in the Excessive hypotonic fluid in the body is called hypotonic overhydration body is called hypotonic overhydration (water excess, dilutional (water excess, dilutional hyponatremia ).hyponatremia ).

Severe water excess causes a Severe water excess causes a serial of symptoms and signs, and is serial of symptoms and signs, and is called water intoxication.called water intoxication.


The main causes are excessive water The main causes are excessive water intake and less loss of water.intake and less loss of water.

1) Excessive water intake1) Excessive water intake

① ①Excessive venous infusion of 5% Excessive venous infusion of 5% glucose solution.glucose solution.

② ②Excessive water intake of psychotic Excessive water intake of psychotic disturbances (e.g. schizophrenia) may disturbances (e.g. schizophrenia) may cause water intoxication. cause water intoxication.

Chicago Daily News Aug. 9, 1958 Chicago Daily News Aug. 9, 1958 reported that the world’s water drinking reported that the world’s water drinking champion (1935) drank 20 L of water champion (1935) drank 20 L of water within 30 min, and was awarded a “hose”. within 30 min, and was awarded a “hose”.

It is obvious that this champion is It is obvious that this champion is healthy (without water intoxication).healthy (without water intoxication).

Excessive water intake only can not Excessive water intake only can not lead to the water intoxication . lead to the water intoxication .

The reason is ???The reason is ???

At the same time, the kidneys At the same time, the kidneys cannot eliminate the excessive cannot eliminate the excessive water.water.

2) Decreased water output2) Decreased water output

① ① Oliguria due to low renal blood flow Oliguria due to low renal blood flow ( in congestive heart failure,cirrhosis).( in congestive heart failure,cirrhosis).

② ② Oliguria due to excessive secretion of Oliguria due to excessive secretion of ADH ADH

Several factors can stimulate the ADH Several factors can stimulate the ADH secretion, like fear, stress, anesthesia, pain secretion, like fear, stress, anesthesia, pain and some drugs (e.g. morphine and and some drugs (e.g. morphine and meperidine), meperidine),

③ ③ Syndrome of inappropriate Syndrome of inappropriate secretion of ADH (SIADH)secretion of ADH (SIADH)

Causes of SIADH are: Causes of SIADH are: pulmonary diseases (viral and bacterial pulmonary diseases (viral and bacterial

pneumonias, tuberculosis, fungal infection, lung pneumonias, tuberculosis, fungal infection, lung abscess), abscess),

diseases of central nervous system ( brain diseases of central nervous system ( brain tumor, brain abscess, encephalitis and tumor, brain abscess, encephalitis and meningitis),meningitis),

tumors of lung, pancreas, thymus and tumors of lung, pancreas, thymus and duodenum (ectopic ADH synthesis)duodenum (ectopic ADH synthesis)

At the same time, fluid intake (intravenous or At the same time, fluid intake (intravenous or oral) is not carefully controlled.oral) is not carefully controlled.

(3) Effects on the body(3) Effects on the body(a) Dilutional hyponatremia(a) Dilutional hyponatremia Low serum protein concentration.Low serum protein concentration. Low serum osmosityLow serum osmosity Increased blood volume.Increased blood volume.(b) A rapid weight gain in acute water (b) A rapid weight gain in acute water

intoxication,intoxication,(c) Cellular overhydration of central nervous (c) Cellular overhydration of central nervous

system.system. Anorexia, nausea, vomitingAnorexia, nausea, vomiting Muscular weakness and twitching Muscular weakness and twitching Mental disturbances, convulsive seizures, Mental disturbances, convulsive seizures,

stupor, and coma. stupor, and coma. (d) Peripheral and pulmonary edema(d) Peripheral and pulmonary edema

5) Principle of treatment5) Principle of treatment

(a) Restriction of water intake(a) Restriction of water intake

(b) Diuretics to excrete the (b) Diuretics to excrete the excessive waterexcessive water

(c) Hypertonic saline (3%NaCl) for (c) Hypertonic saline (3%NaCl) for severe case, to raise the osmolarity severe case, to raise the osmolarity of ECF quickly, to start the of ECF quickly, to start the movement of water from the cells movement of water from the cells into extracellular space, then into extracellular space, then excretion from kidneys.excretion from kidneys.

Case discussionCase discussion

A 25-year-old male has a head A 25-year-old male has a head injury and unable to eat. He received injury and unable to eat. He received 4~5 L of 5%glucose per day to 4~5 L of 5%glucose per day to replace his fluid losses and for replace his fluid losses and for nutritional purposes. On the 5th day nutritional purposes. On the 5th day he experienced convulsions and he experienced convulsions and coma. The followings are his coma. The followings are his laboratory findings.laboratory findings.

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Day Body weight Plasma[Na+] Plasma osmolarityDay Body weight Plasma[Na+] Plasma osmolarity (Kg) (mmol/L) (mOsm/L)(Kg) (mmol/L) (mOsm/L)--------------------------------------------------------------------------------------------------------------------------------------------------------------------------

------------ O 75 140 300O 75 140 300 1 76 137 2951 76 137 295 2 78 130 2802 78 130 280 3 79 125 2703 79 125 270 4 80 120 2604 80 120 260 5 82 115 2505 82 115 250--------------------------------------------------------------------------------------------------------------------------------------------------------------------------

--------

Questions:Questions: (1)What is the problem (pathological process) he (1)What is the problem (pathological process) he

had?had? (2) Is this the normal response to intravenous (2) Is this the normal response to intravenous

infusion of infusion of 5%GS?5%GS? (3)What is the reason of convulsion and coma?(3)What is the reason of convulsion and coma?

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Section II: Disorders of Water and Sodium Metabolism

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