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Daily fluid exchange

≈2 L/day:
Lungs: 0.3 L
Sweat: 0.5 L
Feces: 0.2 L
Urine: 1.0 L

Thirst receptor location


Three paths for fluid return

Capillary return;
Lymphatic return;
Entrance to intracellular compartment

Hypovolemia def & causes

Fluid volume of blood is low;
extreme sweating, v/d, hemorrhage, burns

Hypervolemia def & causes

Fluid volume of blood is too high;
CHF, Chronic RF, Excess IV

Main ICF cation


Main ECF cation


Main ICF anion

P (as PO4)

Main ECF anion


Cation used in coagulation


Cation used in enzyme rxns


Serum [Na]

135-145 mEq/L

Hyponatremia causes

SIADH, Addison's, vomiting/diarrhea, heat stroke, renal failure

Hypernatremia causes

Dehydration, diabetes insipidus, loop diuretics, hyperaldosteronism

Serum [K]

(Na levels, drop "1") 3.5-5.0 mEq/L

Hypokalemia causes & EKG

AAAA + DDD (should ADD K)
Alkalosis, Alcoholism, Anorexia, (hyper)Aldosteronism, Diarrhea/vomiting, Diuretics, Diabetes Insipidus

Hypokalemia EKG

Flat T; U-wave appears. A tach, PVCs --> V tach

Hyperkalemia causes

Acidosis/Addisons, Burns, Crushing injuries, Renal failure

Hyperkalemia EKG

Peaked T; AV block --> V tach --> V fib --> Arrest

Serum [Ca]

8.9-10.1 mg/dL

Hypocalcemia causes

Hypoparathyroidism, Acute Pancreatitis, Vit D deficiency, chemo

Hypocalcemia EKG

Extended QT-interval

Hypercalcemia causes

Pheochromocytoma, Hyperparathyroidism, Adrenal insufficiency, Grave's disease

Hypercalcemia EKG

Shortened QT-interval

Serum [PO4]

2.5-4.5 mg/dL

Hypophosphatemia causes

"Triple A-P-G-S"
Alcoholism, Antacids, Acidosis, pancreatitis, G- sepsis, steroids

Hyperphosphatemia causes

Hypoparathyroidism, tumor lysis (lymphomas) renal insufficiency, rhabdo

Serum [Mg]

1.5-2.5 mEq/L

Hypomagnesemia causes

Hypercalcemia, malnutrition

Hypermagnesemia causes

"DKA-- Lost Insulin Ruins Hearts"
DKA, Hemolysis, Lithium intoxication, Renal failure


Excess ISOTONIC fluid in ECC

Hypervolemia causes

Burns, congestive heart failure, cirrhosis, nephrotic syn, IV

Hypervolemia S/s

Edema, low HCT, normal [Na], low BUN


Low ISOTONIC fluid in ECC

Hypovolemia causes

Fluid loss (hemorrhage, diabetes, diuretics, vomiting) 3rd space shifts (burns, CHF, peritonitis, hypoalbuminemia)

Hypovolemia S/s

Acute weight loss, dizziness, polydipsia, tachy, hypotension

Hyponatremia S/s

Weakness, Neurological path (Brain swells!-- Headache, confusion, seizures, coma)

Hypernatremia S/s

Cardiovascular( tachycardia, hypotension) and Renal (hypernatremic renal failure), polydipsia

Hypokalemia S/s

Atrial tachycardia, V-tach and V-fib. Anorexia, n/v, Weakness, Paresthesias, Dysrhythmias (U wave), sensitivity to digitalis

Hyperkalemia S/s

Dysrhythmias (Peaked T's) MI, Weakness, Paralysis, n/v

Hypocalcemia S/s

Tetany (muscle Clamping), Convulsions, increased QT interval

Hypercalcemia S/s

"Stones, Bones, Groans, Moans & CCCC-QT"
Cramps/weakness, Lack of Coordination, Constipation, Confusion, Cardiac dysrhythmias Shortened QT interval


Severe edema of all tissues, esp subcutaneous tissue

Usual cause of Pitting Edema



Fluid collection in body cavity


Pleural effusion: fluid in lung cavity


Pericardial effusion: fluid in cardiac space


Peritoneal effusion: fluid in abdominal cavity

Two classes of edema

Low protein (transudate) & High protein (exudate)

Two types of low protein (Transudate) edema

Hydrostatic & "back pressure"

Two types of hydrostatic, Low Protein edema

Hypervolemic & Hypernatremia

Causes of Hypervolemic Edema

Hypervolemia: Burns, CHF, Cirrhosis, RF, IV infusion

Causes of Hypernatremia Edema

Hypernatremia: Cushing's; Hyperaldosteronism 2/2 CHF; Loop diuretics

Causes of "Back pressure" Edema

CHF (L-sided causes Pulmonary edema), R-sided causes Portal/Hepatic edema); Venous thrombosis (causes localized edema)

Causes of Osmotic Edema

Cirrhosis & Glomerulonephritis

Two types of high protein edema

Inflammatory & Lymphedema

Characteristics of inflammatory edema

Usually localized, allergic urticaria or Autoimmune

Three types of lymphedema

Scarring (eg, filiriasis [Wucheraria bancrofti]);
Obstructivre (CA);
Surgical (Resection)

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