Block 4: Fluid Imbalances Phys Flashcards
What is homeostasis?
Maintenance of a consistent fluid and electrolyte adjustment
What are electrolytes?
Any substances that dissociate into ions in water
How does excess fluid affect vitals?
- Increases BP
- Edema
- Fluid accumulation in lungs
How does fluid deficit affect vitals?
↑ HR and ↓ BP
What is the primary anion in the ECF?
Chloride
Chloride is proportional to ___ and inversely related to ___
Na+, HCO3-
What are the biological functions of chloride?
- Maintenance of ECF osmolarity and acid-base regulation
- Component of HCl
- Essential for carbon dioxide transport
- Found in cerebrospinal fluid, bile, and pancreatic juices
Abnormally high plasma concentration of chloride is called ___?
Hyperchloremia
What can cause hyperchloremia?
1.Metabolic acidosis
2. Water loss and dehydration
3. Hypernatremia and PTH
4. Hyperkalemia
What are the clinical manifestations of hyperchloremia?
- Dehydration and symptoms
- Similar symptoms of hypernatermia
How does hyperchloremia → metabolic acidosis and hyperkalemia?
- EC H+ → IC
- Cl- remains in EC
- K+ in IC → EC
- No tendency towards hyperkalemia occurs in normochloremic metabolic acidosis → anions enter ICF
Abnormally low plasma concentration of chloride ions is ___?
Hypochloremia
What are the causes of hypochloremia?
- Loss of GI secretion
- Alkalosis (↑ bicarb)
- Volume depletion (burns, diuretics)
What are the clinical manifestations of hypochloremia?
- Similar to hyponatremia
- Cerebral edema
- HA, weakness, N, weight gain
- Shallow respirations
When do serum chloride levels decrease?
Volume depletion → hypovolemia → Activation of RAAS → ↑ Angiotensin II → ↑ aldosterone → ↑ K+ secretion → alkalosis and chloride depletion → failure of pendrin, a chloride/bicarbonate anion exchanger in the collecting duct
What would hypochloremia look like in labs?
- Low sodium levels
- Elevated BUN:CR with GI loss and burns
- Metabolic alkalosis
What are the biological functions of potassium?
- Regulates ICF osmolarity
- RMP
- Na+/K+ pump
- Buffering mechanism
- Facilitates glycogen storage in liver and skeletal muscle cells
- Osmotic pressure in the ICF
Describe the mechanism that increases K+?
Abnormally high plasma concentration of potassium ions is ___?
Hypoerkalemia
What are the complications of hyperkalemia?
- Stresses the CV system → lethal arrhythmias
What can cause hyperkalemia?
- Oversupplematation
- Renal failure
- Tissue trauma and breakdown
- Hypoxia
- Acidosis
- Insulin deficiency
What are the clinical manifestations of hyperkalemia?
- Muscle weakness or paralysis
- Dysrhythmias
- Heart block
- Cardiac arrest
- Neuromuscular irritability, extreme paralysis, anxiety
- N/V/D
What would hyperkalemia look like in labs?
- Elevated BNP, BUN, and Cr
- Decreased serum cortisol
- ECG abnormalities
Abnormally low plasma concentration of potassium ions is ___ which can lead to ___?
Hypokalemia, cardiac arrhythmias
What can cause hypokalemia?
- Decreased K+ intake
- Incomplete K+ replacement
- GI loss
- Fluid overload
Clinical manifestations of hypokalemia?
- Low serum K+
- Cushing disease
- GI loss
- V fib
- Cardiac arrest
Labs of hypokalemia?
Elevated BNP, BUN, and creatinine levels in heart or renal failure.
Electrocardiogram abnormalities:
Flattened T wave.
U wave development.
Cardiac arrest in severe cases.
What are the forms of calcium?
Ionized (most significant), Portein-bound
Fraction of Ca2+ found in blood?
40-50%
What are the biological functions of Ca2+?
- Coagulation
- Muscular contraction
- Cellular electrophysiology and membrane potential.
- Acts as a second messenger in hormonal and neurotransmitter pathways.
Describe the mechanism of Ca2+ increasing
What are the clinical manifestations of hypercalcemia?
- Cardiac, musculoskeletal, and neuromuscular effects → morbidity and mortality.
- Muscle weakness
- Decreased excitability of muscles and nerves from decreased Na
Labs regarding hypercalcemia?
- Elevated PTH
- Elevated Vit D
- Evaluate TSH, T3, and T4
- Shortened QT interval, shortened ST segment, various tachyarrhythmias.
Abnormally low plasma concentration of calcium ions is ___ common in ____
Hypocalcemia; renal failure patients
What causes hypocalcemia?
- Hypoparathyroidism
- Parathyroid gland removal
- Hypomagnesemia, hyperphosphatemia, hypoalbuminemia
- Vitamin D deficiency
- Pancreatitis
- Alkalosis
Clinical manifestations of hypocalcemia?
CNS and neuromuscular excitability
1. Chvostek sign
2. Trousseau sign
3. Ventricular dysrhythmias
4. Decreased blood pressure
5. Muscle and intestinal cramping
6. Hyperactive bowel sounds
7. Osteoporosis
What is a chvostek sign?
Tapping on facial nerve below temple to elicit twitch or spasm of the lower lip on ipsilateral side of tapping
What is Trousseau sign?
Occluding arterial blood flow of the arm for 5 minutes (typically with a blood pressure cuff), eventually causing contraction of the arm and hand
Calcium has an inverse relations with ____
Phosphorus corresponding with hypomagnesemia and hyperphosphatemia.
Biological functions of phosphorus?
- Buffer in acid–base regulation.
- Component in bone and ATP formation.
- Involved in glucose, fat, and protein metabolism
- Maintains control of calcium and phosphate concentrations and vitamin D regulation
- Involved in red blood cell, white blood cell, and platelet function
Abnormally high plasma concentration of phosphate ions is ____?
Hyperphosphatemia
What are the causes of Hyperphosphatemia?
Chronic renal failure
Respiratory acidosis, metabolic acidosis, hypocalcemia, vitamin D excess, chemotherapy
Clinical manifestations of hyperphosphatemia?
- Hypocalcemia
- Paresthesias
- Muscle weakness
- N/V
- Tetany
- Decreased BP
- Cardiac dysrhythmias
- Both Chvostek and Trousseau signs can be elicited
Labs of hyperphosphatemia?
In chronic renal failure:
Elevated BUN and creatinine levels
Elevated PTH
Decreased calcium levels
metabolic or respiratory acidosis
Abnormally low plasma concentration of phosphate ions is ___?
Hypophosphatemia
What causes of hypophosphatemia?
- Malnutrition
- Heat stroke
- Respiratory alkalosis
- Major burns
- HyperPTH
- Chronic diarrhea
- Vitamin D deficiency
Clinical manifestation of hypophosphatemia?
- hypercalcemia
- Red blood cell and platelet dysfunction, bleeding disorders
- Impaired white blood cell function
- Neuromuscular dysfunction
- Altered mental status
- Excessive bone resorption
- Respiratory failure
What are the presentation of hypophosphatemia in malnutrition?
Patient can be cachetic and have low serum albumin and pre-albumin levels
Respiratory alkalosis
What are the presentation of hypophosphatemia in hepatic encephalopathy?
Liver enzymes and serum ammonia can become elevated
What are the presentation of hypophosphatemia in hyperPT?
PTH hormone levels can be elevated
second most common intracellular cation after potassium
Magnesium
How much of Mg is in ECF?
2% most are found in bone
Biological function of Mg2+?
- Inhibits Ca2+ release from SR
- Cofactor in enzymatic reactions
- Plays role in ATP generation, DNA replication, and mRNA production and translation
- Prevents potassium from exiting cardiac cells
- Smooth muscle relaxant
- Neuromuscular integrity
How does Mg regulate PTH?
- required for the production and release of PTH, so when magnesium is too low, insufficient PTH is produced, and blood calcium levels are also reduced (hypocalcemia)
- hypoparathyroidism (with hypocalcemia) can be caused by abnormally high levels of magnesium
Abnormally high plasma concentration of magnesium ions is ?
Hypermagnesemia
What are the causes of hyper magnesia?
Renal failure
magnesium-containing antacids
What are the contributing factors of hyper magnesium?
- Laxative use
- Increased dietary intake
- Lithium toxicity
- Burns, trauma, shock
What are the clinical manifestations?
- Cardiac abnormalities
- Hypotension
- Confusion, lethargy, coma
- Shallow respirations
- Decreased deep tendon reflexes
- Decreased level of consciousness
Abnormally low plasma concentration of magnesium ions is ?
Hypomagnesemia
What causes hypomagnesemia?
- Excessive alcohol intake
- Hypoalbuminemia
Associated with:
Hypocalcemia: Due to decreased PTH secretion.
Hypokalemia: Due to urinary potassium wasting.
Reduced inhibition of the renal outer medullary potassium (ROMK) channel that secretes K+
What are the clinical manifestations of hypomagnesimia?
- Neuromuscular excitability
- Hypokalemia
- Hypocalcemia, hypoparathyroidism, PTH resistance, decreased synthesis of calcitriol.
- Cardiovascular sequelae most worrisome.