Chapter 24: Fluid and Electrolyte Homeostasis and Imbalances
Clinical manifestations of severe symptomatic hypophosphatemia are caused by?
deficiency of ATP
Abnormalities in the intracellular regulation of enzyme activity and cellular production of ATP are associated with
hypophosphatemia *Phosphate is an important component of ATP
A person who overuses magnesium-aluminum antiacids for a long period of time is likely to develop
hypophosphatemia *binds phosphate in the GI tract and prevents absorption
When a parent asks how they will know if their 2-month-old baby, who is throwing up and has frequent diarrhea, is dehydrated, the nurse's best response is
"If the soft spot on the top of his head feels sunken in and his mouth is dry between his cheek and his gums, then he is probably dehydrated."
A patient who reports an intestinal fistula also reports feeling "weak and dizzy" when she stands. While taking her blood pressure she becomes temporarily unresponsive but quickly regains consciousness when put into a supine position. What nursing interventions will the nurse implement before calling the physician?
Give her water or juice and some salty crackers and ask if she has had any diarrhea or vomiting. *Her substantial systolic postural BP decreases with tachycardia and syncope when upright are indicators of ECV deficit - she needs salt and H2O.
The nurse provides teaching regarding dietary intake of K+ to avoid an electrolyte imbalance when a patient
Has chronic HF that is treated with diuretics *Chronic HF causes increased secretion of aldosterone, which causes HypoK+ along with diuretics
A person who has hyperparathyroidism is likely to develop
Hyper Ca++
Decreased neuromuscular excitability is often the result of?
Hyper- Ca and Mg
The imbalance that occurs with oliguric renal failure is
HyperK+
Which electrolyte imbalances cause increased neuromuscular excitbility?
Hypo Ca++ and Mg
An increase in the resting membrane potential (hyperpolarized) is associated with?
HypoK+
A patient has a positive Chvostek sign. The nurse interprets this is a sign of
Increased neuromuscular excitability (Hypo Ca++ and Mg)
What age group has a larger volume of extracellular fluid than intracellular fluid?
Infants
What form of oral rehydration, bottled water or salty broth, is best suited for a patient who is demonstrating signs of clinical dehydration?
Salty soup because it will provide some Na+ to help hold the fluid in his blood vessels and interstitial fluid
S/S of extracellular fluid volume excess include
bounding pulse
Manifestations from Na+ imbalances occur primarily as a result of
cellular fluid shifts
Causes of hypoMg include
chronic ETOH
Effects of HyperNa+ on the CNS typically include
confusion *HyperNa+ causes osmotic shrinking of brain cells
Clinical manifestations of HypoNa+ include
confusion, lethargy, coma, and perhaps seizures *manifestations of CNS dysfunction
How do clinical conditions that increase vascular permeability cause edema?
By allowing plasma proteins to leak into the interstitial fluid, which draws in excess fluid by increasing the interstitial fluid osmotic pressure
A patient diagnosed with chronic compensated HF reports that, "My feet swell if I eat salt but I don't understand why" The nurse's best response is
"Salt holds water in your blood and makes more pressure against your blood vessels, so fluid leaks out into your tissues and makes them swell."
Osmoreceptors located in the hypothalamus control the release of?
ADH
A patient, who is 8 months pregnant, has developed eclampsia and is receiving IV Mg to prevent seizures. To determine if her infusion rate is too high, you should regularly...
Check patellar reflex, it if becomes weak or absent, her infusion rate is probably too high and she is at risk for respiratory depression or cardiac arrest *Remember HyperMg decreases neuromuscular excitability
HyperNa+ may be caused by
Decreased ADH secretion
Which alterations can lead to edema?
Decreased lymphatic flow *lymphatic obstruction prevents drainage of accumulated interstitial fluid and proteins, which can leads to severe edema
Excessive ADH secretion can cause _______ concentration.
Decreased serum Na+
Hyperaldosteronism causes
ECV excess and hypoK+ *Aldosterone retains Na+ and H2O while excreting K+
What is likely to lead to HypoNa+
Frequent NGT irrigation with water
Total body water in older adults is
decreased because of INCREASED adipose tissue and DECREASED muscle mass
The electrolyte that has a higher concentration in the extracellular fluid than in the intracellular fluid is _____ ions.
Na+
How is a patient hospitalized with a malignant tumor that secretes parathyroid hormone-related peptide monitored for the resulting electrolyte imbalance?
Serum Ca, bowel function, and level of consciousness *HyperCa+ causes constipation and lethargy
Which change in a patient's assessment has the greatest urgency?
Serum K+ increasing, developed cardiac dysrhythmias, but denies any difficulty breathing
The inward-pulling force of particles in the vascular fluid is called _____ pressure.
capillary osmotic pressure
S/S of clinical dehydration include
decreased U/O
What is the most likely explanation for a diagnosis of HyperNa+ in an elderly patient receiving TF?
inadequate H2O intake
A known cause of hypokalemia is
insulin overdose *shifts k+ into the cells
Clinical manifestations of moderate to severe hypoK+ include
muscle weakness and cardiac dysrhythmias
The process responsible for distribution of fluid between the interstitial and intracellular compartments is
osmosis
The person at highest risk for developing hyperNa+ is a person who
received TF because he or she is comatose after a stroke *TF are associated with HyperNa+ as a result of intake of highly concentrated solution that causes kidneys to excrete extra water to remove solute load
The fraction of total body water (TBW) volume contained in the intracellular space in adults is
two thirds
Clinical manifestations of extracellular fluid volume deficit include
weak pulse, low BP, and increased HR
