Disorders of fluid, electrolyte and acid base CHAPTER 8 Flashcards
Differentiate intracellular from extracellular compartments in terms of distribution and composition of water, electrolytes and other osmotically active solutes
Intracellular
- contains 2/3 of body water and is larger compartment than extracellular
- lots of K and MG, low NA, CL
- CA
EXTRACELLULAR
- 1/3 body water
- fluid outside cell, tissue spaces, blood vessel
- lots of NA, CL, bicarbonate
Describe the control of cell volume and the effects of isotonic, hypotonic, and hypertonic solutions on cell size
- cell volume is controlled by diffusion and osmosis
- movement of high to low gradient
ISOTONIC
-no difference in solute concentration = same cell
Hypotonic
-high solute concentration inside cell = swollen cell
Hypertonic
-low solute concentration inside cell = crenated cell/shrink
Describe factors that control fluid exchange between the vascular and interstitial fluid compartments and relate them to the development of edema and third spacing in extracellular fluid
4 factors:
Capillary filtration - water is pushed from capillary to interstitial
Capillary colloidal osmotic pressure (proteins) - water is pulled into the capillary (decreased protein causes edema)
Interstitial hydrostatic pressure - which opposes the movement of water out of the capillary
Interstitial colloidal osmotic pressure - water pulls out of the capillary into the interstitial space
Describe the consequences and treatment of edema
Increases distance for diffusion of oxygen, nutrients and wastes
Tissues more susceptible to injury
Pressure ulcers
Compresses blood vessels and nerves (tourniquet)
Disfiguring
Self-concept disturbances
Improper fitting of clothes
TREATMENT -Elevation Diuretics Albumin Massage Elastic support stockings Range of motion exercises
describe the cause, manifestation and treatment of psychogenic polydipsia
- compulsive water drinking in those with psychiatric disorders
- drinks large amount of water and urinates a lot
- cause unknown, idiopathy
MANIFESTATION
-drink a lot, pee a lot
TREATMENT
- water restriction
- behaviour control to decrease water consumption
Describe the relationship between body water and the extracellular sodium concentration
-the distribution of body fluids between the ICF and ECF compartments relies on the concentration of ECF sodium and water
Describe pathophysiology, manifestations, and treatments of diabetes insipidus
- deficiency of a decreased response to ADH
- neurgenic (not secreting enough ADH)
- nephrogenic (kidney not responding)
- unable to concentrate urine, during periods of water restriction and they excrete large volumes of urine
MANIFESTATION
- intense thirst, craving ice water, excess urination
- hypernatremia, dehydration
TREATMENT
- give ADH
- diuretics
pathophysiology, manifestations, and treatment of syndrome of inappropriate antidiuretic hormone
-failure of the negative feedback system that releases ADH which causes continued ADH secretion
MANIFESTATION
- water retention
- hyponatremia
- urine output decreases despite increase water intake
- water intoxication
- extremely low sodium level
TREATMENT
- fluid restriction
- diuretics
- lithium and antibiotics inhibits the action of ADH
State the causes and manifestations of hypokalemia
-inadequate intake, excessive loss (GI tract, diuretics)
- movement of K from bloodstream into cell
- increased insulin, alkalosis
MANIFESTATION (usual gradual)
- GI: anorexia, N&V, constipation
- CNS: muscle weakness, fatigue, parathesia, paralysis
- CVS: ventricular arrhythimas, ECG changes, digoxin toxicity (if taking)
State the causes and manifestations of hyperkalemia
- decreased excretion
- adrenal insufficiency, ACE inhibitors
- chronic kidney disease
- increased intake
- increased movement of K from cells into blood stream
- acidosis, tissue injury, decreased insulin, bblockers
MANIFESTATION
-CVS: bradycardia, cardiac arrest
-CNS: weakness, paresthsia, paralysis
GI: cramps, diarrhea, n&v
describe hypocalcemia and hypercalcemia and their causes and manifestation
causes of hypo - decreased intake, abnormal loss, hypoparathyroidism, vitamin D deficiency
MANIFESTATION
-muscular: tetany, muscle cramps. carpopedal spasm (trouseau’s sign)
CNS: chvostek’s sign, paresthesia, confusion, lethargy, anxiety
CVS: prolonged QT. reistance to digitalis, hypotension
causes of hyper - neoplasms of parathyroid glands, immobilization, poor absorption
MANIFESTATION
-muscular: weakness, ataxia
CNS: lethargy, personality changes, stupor, coma
CNS: hypertension, short QT, AV blocks
GI: Anorexia, n&v, constipation
GU: interferes with ADH so can’t cncentrate urine
Describe hypomagnesemia and hypermagnesemia their causes and manifestation
causes of hypo - insufficient intake, excessive loss, movement between ECF and ICF
MANIFESTATION
- manifestation are ususally due to related electrolyte disorders
- increased in neuromuscular excitability
- hyperactive deep tendon reflex
- paresthesias, muscle fasciculation, and muscle contraction
- positive chvostek or trousseau sign present
- seizure
- ataxia, vertigo, disorientation
causes of hyper - renal insufficiency or excessive intake (antacids, laxatives)
MANIFESTATION
- hypocalcemia may accompany hypermagnesemia
- muscle weakness, hyporeflexia
- low bp
- ECG increase in PR interval, shortening of QT, t wave abnormal and prolong QRS
- severe is muscle respiratory paralysis. heart block and cardiac arrest
Describe the three forms of carbon dioxide transport and their contribution to acid-base balance
- in circulation as dissolved base (pCO2)
- as bicarbonate (HCO3)
- as carbaminohemoglobin
List the three major mechanisms of pH regulation
- chemical buffer systems
- respiratory control mechanism
- renal control mechanism
compare the role of the kidneys and respiratory system in regulation of acid-base balance
- Kidneys regulates pH by secreting of excess H and re-absorption of HCO3 (bicarbonate) by the renal tubules. Each bicarbonate that s reclaimed requires the secretion of H, a process that is tightly coupled with sodium reabsorption.
- increased ventilation decreases carbon dioxide in the blood. While decreased ventilation increases. Chemoreceptors in the brain and in the carotid sense changes in the blood CO2 and pH and alters the ventilatory rate
- if cause of an acidosis or alkalosis is respiratory, the kidney will compensate
- if the cause is renal, the lung will compensate
Causes of metabolic acidosis and manifestation
-causes loss of bicarbonate via kidney or GI tract
-diarrhea
-excess production/accumulation of acids (liver disease, ketoacidosis, drugs, rhabdomyolysis
-inability of kidney to excrete excess acid
CNS: head ache, lethargy, kussmaul breathing
RESP: hyperventilation
CVS: hypotension
GI: anorexia
Causes of metabolic alkalosis and manifestation
- causes is increase in plasma bicarbonate(HCO3)
- excess H ion loss: vomitting, gastric suctioning
- excess bicarbonate (HCO3): ingestion of alkali
- loss of K ion d/t renal excretion: diuretics hyperaldosteronism
MANIFESTATION
CNS: hyperactive reflexes, tetany, confusion, seizures, trousseau’s sign
RESP: bradypnea, shallow
CVS: hypotension, arrhthimias
GI: n&v
pH >7.45
HCO3 >26
Causes of respiratory acidosis and manifestation
-causes increased CO2
-over production of CO2 from sepsis, burns, hyperthermia
-inspiration of CO2
-decreased expiration of CO2:
obstruction, lung chest wall damage, hypoventilation, asphyxia, devervation of muscle, damage to muscles
MANIFESTATION
CNS: headache, restlessness, confusion, depressed reflexes, comnolence, coma
RESP: dyspnea, tachypnea, hypoxemia
CVS: tachycardia, arrythmias, hypertension or hypotension
Causes of respiratory alkalosis and manifestation
-decrease in pCO2 (hypocapnia)
-hyperventilation from anxiety, pain, fever, anemia, high altitude, medularry stimulation, mechanical ventilation, disease processes
Medication: salicylate OD
MANIFESTATION
CNS: dizzy, agitated. circumoral and peripheral paresthesia, tetany, twitching, muscle weakness
RESP: deep, rapid respiration
CVS: increased in HR
Explain the purpose of arterial blood gas analysis
- assessing respiratory and metabolic function
- venous blood gases unreliable because it varies
