PST2235 - Module 2: Fluid balance & Electrolyte Disorders flashcards

All 99 cards

1. Card 1

   Define 'electrolytes' and explain their significance in maintaining fluid balance within the body.

   Electrolytes are salt substances that dissociate into charged ions (cations and anions) when dissolved in water. Their significance lies in their ability to disturb vital functions if their concentrations change, and they also drive fluid movement due to the creation of concentration gradients across membranes.

2. Card 2

   How does osmosis differ from simple diffusion, and what role does a semi-permeable membrane play in osmosis?

   Simple diffusion involves the movement of solid matter from an area of high concentration to low concentration until even distribution. Osmosis, however, is specifically the diffusion of water through a selectively permeable membrane from a less concentrated solution to a more concentrated solution. The semi-permeable membrane is crucial as it regulates the movement of solutes and water, allowing water to pass while restricting certain solutes, thus enabling osmotic pressure to build and drive water movement.

3. Card 3

   A patient is admitted with severe dehydration, and their cells are showing signs of shrinking. Which type of intravenous fluid would be most appropriate to administer, and why?

   A hypotonic solution would be most appropriate. This type of solution has a lower solute concentration than normal cells, meaning that when infused, water will be drawn from the solution into the patient's cells, helping to rehydrate them and reverse the cellular shrinking caused by dehydration.

4. Card 4

   Describe the two main fluid compartments of the body and state the approximate percentage of total body weight each accounts for.

   The two main fluid compartments are Intracellular Fluid (ICF) and Extracellular Fluid (ECF). ICF is the fluid found inside all body cells and accounts for approximately 40% of total body weight. ECF is the fluid found outside the cells, including intravascular and interstitial compartments, and accounts for about 20% of total body weight.

5. Card 5

   What is the primary goal of fluid and electrolyte balance in the human body?

   The primary goal of fluid and electrolyte balance in the human body is to maintain homeostasis. This means ensuring a relatively constant internal environment where the amount of water gained equals the amount lost, and the rate of electrolyte absorption matches the rate of excretion.

6. Card 6

   Which of the following describes the movement of substances against their concentration gradient, requiring cellular energy?

   C) Active transport. Active transport actively moves substances from an area of low concentration to high concentration, which requires cellular energy to overcome the concentration gradient.

7. Card 7

   Explain how fever affects fluid balance in the body.

   Fever significantly increases fluid loss from the body. For every degree of increase in temperature, water loss increases by approximately 200ml per day, primarily through increased perspiration and respiration. This heightened loss can quickly lead to dehydration if not compensated for.

8. Card 8

   A patient's blood test shows an abnormally high concentration of sodium outside their cells. How would this electrolyte imbalance likely affect fluid movement between their cells and the extracellular fluid?

   An abnormally high concentration of sodium (a solute) outside the cells would create a hypertonic environment in the extracellular fluid. According to the principle 'water follows salt,' water would be drawn out of the cells and into the extracellular fluid to equalize the concentration gradient. This could lead to cellular dehydration and shrinking.

9. Card 9

   What is a 'concentration gradient' and how does it drive fluid movement?

   A concentration gradient is the difference in the concentration of a solute between two areas. It drives fluid movement because substances, including water, tend to move from an area of higher concentration to an area of lower concentration, or vice versa, to achieve equilibrium. This movement can occur through diffusion or osmosis.

10. Card 10

    Distinguish between 'sensible' and 'insensible' fluid losses, providing an example of each.

    Sensible fluid losses are those that are noticed and measurable, such as urine and perspiration (sweat). Insensible fluid losses are those that are unnoticed and difficult to measure, such as water lost through respiration and evaporation from the skin (non-sweat).

11. Card 11

    How does the body gain fluid, beyond simply drinking water?

    The body gains fluid not only through ingestion of food and water but also through metabolic generation. Metabolic generation refers to the synthesis of water that occurs at the end of the electron transport chain during cellular respiration, contributing a small but significant amount to daily fluid intake.

12. Card 12

    A nurse is preparing to administer an intravenous fluid that is isotonic. What effect should the nurse expect this fluid to have on the patient's cells if they are normally hydrated?

    The nurse should expect no net movement of water molecules into or out of the patient's cells. An isotonic solution has a solute concentration similar to normal body cells, meaning it will not cause cells to swell or shrink when infused into a normally hydrated patient.

13. Card 13

    Why is water considered essential for the human body, beyond just being a component of body weight?

    Water is essential because it serves as the medium in which all metabolic reactions occur, facilitating biochemical processes vital for life. Additionally, the precise regulation of its volume, distribution, and composition is critical for maintaining overall bodily health and homeostasis.

14. Card 14

    What are 'carrier molecules' and what is their role in fluid and electrolyte balance?

    Carrier molecules are proteins that facilitate the movement of large, water-soluble, or electrically charged molecules across cell membranes. They combine with solute molecules on one side of the membrane, change shape to pass through, and then release the solute on the other side, playing a key role in mediated transport mechanisms.

15. Card 15

    A patient presents with severe edema, indicating excess fluid in the interstitial spaces. Which type of intravenous fluid might a physician consider to draw fluid out of these spaces and why?

    A physician might consider a hypertonic solution. A hypertonic solution has a higher solute concentration than normal cells, which would create an osmotic gradient. This would draw excess water from the interstitial fluid (and potentially from cells) into the intravascular compartment, helping to reduce the edema.

16. Card 16

    What is the approximate percentage of total body weight accounted for by water in a healthy adult?

    Water accounts for approximately 50-60% of the total body weight of a healthy adult. This significant proportion highlights its fundamental role in physiological processes.

17. Card 17

    Which of the following components makes up approximately 55% of blood composition?

    C) Plasma. Plasma accounts for approximately 55% of blood composition and consists of water, electrolytes, solutes, and plasma proteins, while formed elements make up the remaining 45%.

18. Card 18

    How does 'facilitated diffusion' differ from 'active transport' in terms of energy requirement and direction of movement?

    Facilitated diffusion moves substances with the concentration gradient (from high to low concentration) and does not require cellular energy. Active transport, conversely, moves substances against the concentration gradient (from low to high concentration) and explicitly requires cellular energy to do so.

19. Card 19

    A patient's kidneys are failing to excrete sufficient electrolytes, leading to an accumulation in the body. How would this situation relate to the concept of electrolyte balance?

    This situation represents an electrolyte imbalance because electrolyte balance is achieved when the rate of absorption across the digestive tract matches the rate of excretion from the kidneys, sweat glands, etc. Kidney failure to excrete would disrupt this balance, leading to an excess of electrolytes in the body.

20. Card 20

    What is 'osmotic pressure' and what factors influence its magnitude?

    Osmotic pressure is the force required to prevent the movement of water across a selectively permeable membrane during osmosis. Its magnitude is dependent on the number and molecular weight of particles on each side of the membrane, as well as the membrane's permeability to those particles.

21. Card 21

    A marathon runner collapses due to severe dehydration and electrolyte loss through excessive sweating. Their medical team needs to quickly rehydrate and restore electrolyte balance. What type of fluid replacement strategy should they prioritize, considering both water and electrolyte needs?

    The medical team should prioritize administering an isotonic solution that also contains essential electrolytes. While water is crucial for rehydration, the loss of electrolytes through sweat means simply providing pure water could further dilute remaining electrolytes, worsening the imbalance. An isotonic electrolyte solution would help replenish both fluid volume and electrolyte concentrations without causing significant fluid shifts into or out of cells.

22. Card 22

    What are the two main components of blood composition, and what do they primarily consist of?

    The two main components of blood composition are formed elements and plasma. Formed elements (approx. 45%) consist of platelets, white blood cells, and red blood cells. Plasma (approx. 55%) consists of water, electrolytes, solutes, and plasma proteins.

23. Card 23

    Which fluid compartment includes blood plasma, and what percentage of the ECF does blood plasma compose?

    Blood plasma is part of the Extracellular Fluid (ECF) compartment. Blood plasma composes about 1/3 of the ECF.

24. Card 24

    Define 'homeostasis' in the context of fluid and electrolyte balance.

    In the context of fluid and electrolyte balance, homeostasis refers to the maintenance of a relatively constant internal environment. This means ensuring that the amount of water gained each day equals the amount lost, and that the rate of electrolyte absorption matches the rate of excretion.

25. Card 25

    A patient is experiencing a condition where their body is retaining too much water, leading to diluted electrolyte concentrations. Which type of solution, if administered, would exacerbate this condition by drawing more water into the cells?

    A hypotonic solution would exacerbate this condition. A hypotonic solution has a lower solute concentration than normal cells, meaning it would cause water to be drawn from the solution into the cells, further diluting intracellular electrolytes and potentially worsening cellular swelling.

26. Card 26

    Define osmosis and explain the factors that influence osmotic pressure.

    Osmosis is the diffusion of water through a selectively permeable membrane from a less concentrated solution to a more concentrated solution. Osmotic pressure, which is the force required to prevent this water movement, is dependent on the number and molecular weight of particles on each side of the membrane, as well as the membrane's permeability to those particles.

27. Card 27

    A patient is admitted with severe dehydration. The medical team is considering administering an IV fluid. Which type of solution, hypotonic, isotonic, or hypertonic, would be most appropriate to rehydrate the patient's cells without causing further fluid shifts, and why?

    An isotonic solution would be most appropriate. When an isotonic solution is infused into a normally hydrated patient, there is no net movement of water molecules, meaning water is neither drawn out of the cells nor moved into them. In a dehydrated patient, this helps to restore overall fluid volume without causing cellular swelling or shrinkage, which could exacerbate the patient's condition.

28. Card 28

    Distinguish between active transport and facilitated diffusion, highlighting their key differences.

    Both active transport and facilitated diffusion are carrier-mediated transport mechanisms that move substances across cell membranes at a faster rate than simple diffusion. The key difference is that active transport moves substances against a concentration gradient (low to high) and requires cellular energy, while facilitated diffusion moves substances with the concentration gradient (high to low) and does not require cellular energy.

29. Card 29

    Which of the following hormones is secreted by the posterior pituitary gland and reduces urine production by making distal and collecting tubules permeable to water? A) Aldosterone B) Atrial Natriuretic Factor (ANF) C) Antidiuretic Hormone (ADH) D) Renin

    C) Antidiuretic Hormone (ADH). ADH is secreted by the posterior pituitary gland and works to reduce the amount of urine produced by increasing the permeability of the distal and collecting tubules to water, thereby raising blood pressure by retaining H2O in the body.

30. Card 30

    Explain the role of aldosterone in maintaining fluid and electrolyte balance.

    Aldosterone, secreted by the adrenal gland, plays a crucial role in fluid and electrolyte balance by stimulating the distal tubules in the kidneys to reabsorb sodium and water, while simultaneously secreting potassium. This action helps to retain H2O in the body, which in turn raises blood pressure, and is triggered by a decrease in sodium levels or an increase in potassium levels.

31. Card 31

    A patient presents with symptoms including muscle weakness, twitching, fatigue, and cerebral oedema. Lab results show a serum sodium level of 125 mEq/L (normal range 135-145 mEq/L). What electrolyte imbalance is the patient likely experiencing, and what is the primary concern for treatment?

    The patient is likely experiencing hyponatraemia, which is an abnormally low sodium level in the blood. The primary concern for treatment is to address the low sodium and the resulting fluid shifts, particularly cerebral oedema. Treatment often involves IV fluid replacement, such as normal saline, and in severe cases like seizures, hypertonic saline may be used.

32. Card 32

    How does the Renin-Angiotensin-Aldosterone System (RAAS) contribute to blood pressure regulation?

    The RAAS regulates blood pressure by initiating a cascade of events. Renin, secreted by the kidneys in response to reduced blood volume, converts angiotensinogen to angiotensin I. Angiotensin I is then converted to angiotensin II by ACE in the lungs. Angiotensin II is a potent vasoconstrictor, directly raising blood pressure, and also stimulates aldosterone secretion, which further increases blood pressure by promoting sodium and water reabsorption.

33. Card 33

    What is the main extracellular fluid (ECF) cation, and how does it influence osmotic forces?

    Sodium (Na+) is the main ECF cation. It significantly regulates osmotic forces because 'water follows salt'. This means that changes in ECF Na+ concentration directly impact water movement between fluid compartments, thus affecting overall fluid balance and osmotic pressure.

34. Card 34

    A patient is diagnosed with hypernatraemia. What are the two main physiological mechanisms that can lead to this condition, and which is generally more common?

    Hypernatraemia can result from either too much sodium gain or too much water loss. While sodium excess can occur from hypertonic fluid administration or excess aldosterone, water deficit is generally more common. This is often due to impaired thirst reflexes, inability to access water (e.g., in infants, elderly), or conditions like diabetes mellitus or insipidus.

35. Card 35

    Explain why mediated transport mechanisms are necessary for certain molecules to cross cell membranes.

    Mediated transport mechanisms are necessary because large, water-soluble molecules (like glucose) or electrically charged molecules cannot easily diffuse directly through the lipid bilayer of the cell membrane. These mechanisms, often involving carrier proteins, provide specific pathways for such substances to move into or out of cells, either with or against their concentration gradients.

36. Card 36

    Which of the following describes the effect of a hypotonic solution on normal cells? A) Water is drawn from the cells into the solution. B) There is no net movement of water molecules. C) Water is drawn from the solution into the cells. D) The cells crenate due to water loss.

    C) Water is drawn from the solution into the cells. A hypotonic solution has a lower solute concentration than normal cells, causing water to move by osmosis from the solution into the cells to equalize the solute concentration.

37. Card 37

    A patient with heart failure is experiencing fluid overload. The body's response includes the secretion of Atrial Natriuretic Factor (ANF). How does ANF help to counteract this fluid overload?

    Atrial Natriuretic Factor (ANF) helps to counteract fluid overload by being secreted in response to increased pressure in the right atrium. ANF inhibits ADH secretion and reduces the kidneys' ability to concentrate urine, leading to the production of large volumes of dilute urine. This process excretes H2O from the body, thereby lowering blood pressure and reducing fluid volume.

38. Card 38

    A nurse is administering a hypertonic saline solution to a patient experiencing severe hyponatraemia with neurological symptoms. Explain the physiological rationale behind using a hypertonic solution in this specific scenario.

    In severe hyponatraemia, especially with neurological symptoms like cerebral oedema, the extracellular fluid has a lower solute concentration than the intracellular fluid, causing water to shift into brain cells and swell. Administering a hypertonic saline solution, which has a higher solute concentration, creates an osmotic gradient that draws excess water out of the swollen brain cells and back into the extracellular space, helping to reduce cerebral oedema and alleviate neurological symptoms.

39. Card 39

    What is the primary function of potassium (K+) in the body, and why is its concentration kept within a very narrow range?

    Potassium (K+) is the main positively charged ion in the intracellular fluid and is crucial for maintaining the normal function of nerves, cardiac, and skeletal muscle. It plays a significant role in action potentials, enzyme action, glycogen storage, and acid/base balance. Its concentration is kept within a very narrow range (3.5-5.5 mEq/L) because even slight deviations can severely impair these vital functions, particularly cardiac rhythm and neurological activity.

40. Card 40

    Describe the process by which carrier molecules facilitate transport across cell membranes.

    Carrier molecules are proteins that facilitate transport by combining with solute molecules on one side of the cell membrane. Upon binding, they undergo a conformational change, allowing them to pass through the membrane and release the solute on the other side. This mechanism is essential for moving substances that cannot freely diffuse across the membrane.

41. Card 41

    What are the six main electrolytes involved in fluid balance?

    The six main electrolytes involved in fluid balance are Sodium (Na+), Potassium (K+), Calcium (Ca2+), Phosphate (PO43-), Magnesium (Mg2+), and Chloride (Cl-).

42. Card 42

    A patient with chronic kidney disease is unable to excrete potassium effectively. What electrolyte imbalance is this patient at risk for, and what are some potential consequences?

    This patient is at risk for hyperkalaemia, which is an abnormally high potassium level in the blood. Potential consequences include significant impacts on cardiac function, potentially leading to arrhythmias and cardiac arrest, as well as muscle weakness and neurological symptoms, due to potassium's critical role in nerve and muscle excitability.

43. Card 43

    Which of the following is NOT a cause of hyponatraemia? A) Severe haemorrhage B) Hyper-secretion of ADH C) Excessive use of diuretics D) Impaired thirst reflexes

    D) Impaired thirst reflexes. Impaired thirst reflexes are a cause of hypernatraemia (due to water deficit), not hyponatraemia. Severe haemorrhage, hyper-secretion of ADH, and excessive use of diuretics can all lead to hyponatraemia.

44. Card 44

    How does the body typically respond to an increase in circulating blood volume in terms of hormonal regulation?

    In response to an increased circulating blood volume, the cells of the right atrium secrete Atrial Natriuretic Factor (ANF). ANF counteracts the increased volume by inhibiting ADH secretion and reducing the kidneys' ability to concentrate urine, leading to increased excretion of water and a subsequent lowering of blood pressure.

45. Card 45

    A patient is experiencing prolonged gastrointestinal upsets, including severe vomiting and diarrhea. What electrolyte imbalance is a significant risk for this patient, and why?

    This patient is at significant risk for hypokalaemia (abnormally low potassium) and hyponatraemia (abnormally low sodium). Severe GI upsets lead to excessive loss of both potassium and sodium from the body, which are critical for maintaining fluid balance and cellular function.

46. Card 46

    Define an isotonic solution and describe its effect when infused into a normally hydrated patient.

    An isotonic solution is a solution in which there is no net movement of water molecules. When an isotonic solution is infused into a normally hydrated patient, water is neither drawn out of the cells nor moved into them, as the solute concentration of the solution is similar to that of the body's cells.

47. Card 47

    Imagine a scenario where a patient has a tumour causing excessive secretion of ADH. What fluid imbalance would you expect, and what are the likely clinical manifestations?

    Excessive ADH secretion would lead to dilutional hyponatraemia, as ADH causes the body to retain too much water, diluting the sodium concentration. Clinical manifestations would include symptoms of hyponatraemia such as muscle weakness, twitching, fatigue, and critically, cerebral oedema due to fluid shifting into brain cells.

48. Card 48

    What is the primary regulatory system for water balance in the body, and what other factors work in conjunction with it?

    Water balance is primarily regulated by the renal system. It works in conjunction with a number of hormones, including Aldosterone, Antidiuretic Hormone (ADH), and Atrial Natriuretic Factor (ANF), as well as the thirst mechanism, to maintain overall fluid homeostasis.

49. Card 49

    Which of the following statements about the Renin-Angiotensin-Aldosterone System (RAAS) is correct? A) Renin is secreted by the liver in response to high blood pressure. B) Angiotensin II is converted to Angiotensin I by ACE in the lungs. C) Angiotensin II is a potent vasoconstrictor and stimulates aldosterone secretion. D) Aldosterone inhibits the reabsorption of sodium and water.

    C) Angiotensin II is a potent vasoconstrictor and stimulates aldosterone secretion. Renin is secreted by the kidneys, Angiotensin I is converted to Angiotensin II by ACE, and aldosterone stimulates the reabsorption of sodium and water, not inhibits it.

50. Card 50

    Explain the concept of 'water follows salt' in the context of sodium's role in fluid balance.

    The concept 'water follows salt' means that water moves passively across semi-permeable membranes from an area of lower solute (salt) concentration to an area of higher solute (salt) concentration to achieve equilibrium. Since sodium is the main ECF cation, its concentration significantly dictates the osmotic forces, meaning changes in sodium levels directly influence where water moves within the body's fluid compartments, thereby regulating overall fluid volume.

51. Card 51

    Explain how hypernatremia leads to neurological symptoms.

    Hypernatremia causes an increase in the extracellular sodium concentration. This draws fluid out of the cells, including brain cells, leading to intracellular dehydration. The crenation (shrinking) of brain cells can manifest as various neurological symptoms.

52. Card 52

    DEFINITION: Distinguish between the causes of hypokalemia and hyperkalemia.

    Hypokalemia is typically caused by reduced dietary intake, poor absorption, increased GI losses (vomiting, diarrhea), renal disease, or certain medications like diuretics. Hyperkalemia, on the other hand, is often caused by acute or chronic renal failure, crush injuries, severe infections, excessive use of potassium salts, or a shift of potassium from cells into the ECF.

53. Card 53

    A) Peaked T wave on ECG B) Muscle weakness and cramps C) Abdominal distention D) Irritability

    B) Muscle weakness and cramps. Hypokalemia often presents with muscle weakness, cramps, paralysis, and arrhythmias, along with a flattened T wave and prominent U wave on ECG. Peaked T waves, abdominal distention, and irritability are more indicative of hyperkalemia.

54. Card 54

    A patient presents with severe muscle weakness, respiratory distress, and an ECG showing a flattened T wave and prominent U wave. What electrolyte imbalance is most likely, and what immediate treatment might be initiated?

    The patient's symptoms and ECG findings are classic for hypokalemia. Immediate in-hospital treatment would likely involve intravenous or oral administration of potassium to replenish the deficient levels.

55. Card 55

    Why is hyperkalemia considered more dangerous than hypokalemia?

    Hyperkalemia is considered more dangerous primarily due to its profound effects on cardiac conduction. High potassium levels can lead to severe cardiac arrhythmias, including ventricular fibrillation and asystole, which can be life-threatening if not rapidly addressed.

56. Card 56

    DEFINITION: What is the primary role of potassium (K+) in the body?

    Potassium is the main positively charged ion in the intracellular fluid (ICF). It is essential for maintaining the normal function of nerves, cardiac, and skeletal muscle, playing a significant role in action potentials, enzyme action, glycogen storage, and acid-base balance.

57. Card 57

    A) Hypertonic fluid administration B) Excess aldosterone secretion C) Diabetes insipidus D) Excessive dietary sodium intake

    C) Diabetes insipidus. Diabetes insipidus leads to excessive water loss, which can cause hypernatremia due to a water deficit. Hypertonic fluid administration and excess aldosterone secretion are causes of hypernatremia due to sodium excess, while excessive dietary sodium intake is rare as a primary cause due to the thirst reflex.

58. Card 58

    A patient with chronic renal failure is admitted with an ECG showing peaked T waves and reports muscle weakness and nausea. What electrolyte imbalance is suspected, and what emergency treatment might be considered?

    The symptoms and ECG findings suggest hyperkalemia, which is common in chronic renal failure. In life-threatening emergencies, intravenous calcium can be given to stabilize cardiac membranes, and administration of glucose and insulin or sodium bicarbonate can help shift potassium back into cells.

59. Card 59

    How does the administration of glucose and insulin help treat hyperkalemia?

    The administration of glucose and insulin helps treat hyperkalemia by effectively forcing potassium to enter the cells along with glucose. Insulin stimulates the cellular uptake of glucose, and potassium follows glucose into the cells, thereby lowering serum potassium levels.

60. Card 60

    DEFINITION: Define hypocalcemia and list two common causes.

    Hypocalcemia is an abnormally low level of calcium in the blood. Common causes include endocrine dysfunction, particularly an underactive parathyroid gland, and renal insufficiency, which can impair vitamin D activation necessary for calcium absorption.

61. Card 61

    A) Hypotonicity of muscles B) Renal stones C) Tetany and muscle twitching D) Deep bone pain

    C) Tetany and muscle twitching. Hypocalcemia increases neural excitability, leading to symptoms like paraesthesia, tetany, and muscle twitching. Hypotonicity of muscles, renal stones, and deep bone pain are associated with hypercalcemia.

62. Card 62

    A patient undergoing chemotherapy develops numbness and tingling around the mouth, muscle cramps, and twitching. Blood tests confirm low calcium levels. What is the likely diagnosis, and what is the typical in-hospital treatment?

    The patient's symptoms are indicative of hypocalcemia. In-hospital treatment typically involves the intravenous administration of calcium ions to rapidly correct the deficiency, often followed by oral calcium salts and Vitamin D supplementation.

63. Card 63

    Explain the inverse relationship between calcium and phosphate.

    Calcium and phosphate have an inverse relationship, meaning that when one increases, the other tends to decrease, and vice versa. This balance is crucial for bone health and is primarily regulated by parathyroid hormone (PTH) and calcitonin, which influence their absorption, excretion, and movement between bone and blood.

64. Card 64

    DEFINITION: What are the main body functions that calcium is essential for?

    Calcium is essential for several critical body functions, including neuromuscular transmission, cell membrane permeability, hormone secretion, growth and ossification of bones, and the contraction of smooth, cardiac, and skeletal muscles.

65. Card 65

    A) Paraesthesia B) Abdominal cramps C) Renal stones D) Convulsions

    C) Renal stones. Hypercalcemia can lead to the deposition of calcium in various tissues, including the renal system, causing renal stones. Paraesthesia, abdominal cramps, and convulsions are more characteristic of hypocalcemia.

66. Card 66

    A patient with a history of hyperparathyroidism presents with altered mental status, deep bone pain, and reports frequent urination. What electrolyte imbalance is suspected, and what is a primary goal of treatment?

    The patient's symptoms, especially with hyperparathyroidism, suggest hypercalcemia. A primary goal of treatment is to control the underlying disease, along with hydration and potentially drug therapy like forced diuresis or calcium-lowering medications.

67. Card 67

    How does severe hypophosphatemia affect the body's energy levels and oxygen utilization?

    Severe hypophosphatemia leads to decreases in the body's energy levels and oxygen utilization because phosphate is a crucial component in ATP (adenosine triphosphate) production, which is the primary energy currency of cells. Without adequate phosphate, cellular energy processes and oxygen transport are impaired, leading to symptoms like fatigue and muscle weakness.

68. Card 68

    DEFINITION: What is hyperphosphatemia, and what is its most common cause?

    Hyperphosphatemia is an abnormally high level of phosphate in the blood. Its most common cause is impaired renal excretion, as the kidneys are primarily responsible for excreting excess phosphate from the body.

69. Card 69

    A) Impaired renal excretion B) Hyperparathyroidism C) Crush injuries D) Excessive dietary phosphate intake

    B) Hyperparathyroidism. Hyperparathyroidism increases serum calcium, which inversely decreases phosphate levels by promoting renal phosphate excretion. Impaired renal excretion and excessive dietary phosphate intake cause hyperphosphatemia, while crush injuries can cause hyperkalemia.

70. Card 70

    A patient with a history of alcohol abuse is admitted with profound fatigue and muscle weakness. Blood tests reveal significantly low phosphate levels. What is the likely diagnosis, and what are potential risks associated with this imbalance?

    The patient likely has hypophosphatemia, which is a known complication of alcohol abuse. Potential risks associated with this imbalance include respiratory failure due to muscle weakness, ischemia, hypotension, abnormal clotting, and an increased risk of infection, all stemming from decreased energy levels and impaired oxygen utilization.

71. Card 71

    Why is a rapid, thready pulse, diaphoresis, and cyanosis listed as signs of a fluid shift back into cells?

    These symptoms are associated with hyponatremia, where fluid shifts back into cells causing swelling and tissue oedema. The rapid, thready pulse, diaphoresis, and cyanosis indicate a compensatory response to decreased circulating blood volume and impaired tissue perfusion as fluid moves from the vascular space into the cells.

72. Card 72

    DEFINITION: What is oliguria, and which electrolyte imbalance is it a sign of?

    Oliguria is the production of abnormally small amounts of urine. It is a sign of hypernatremia, specifically when caused by water deficit, as the body attempts to conserve fluid in response to intracellular dehydration and decreased circulating volume.

73. Card 73

    A) Oral potassium supplements B) Normal saline IV C) Intravenous calcium D) Furosemide

    C) Intravenous calcium. In life-threatening emergencies with severe hyperkalemia, intravenous calcium is administered to stabilize cardiac cell membranes and prevent arrhythmias. Oral potassium supplements would worsen hyperkalemia, normal saline is for volume replacement, and furosemide is a diuretic.

74. Card 74

    A nurse is caring for an elderly patient who is confused and has dry, sticky mucous membranes and flushed, doughy skin. The patient has limited access to water. What electrolyte imbalance should the nurse suspect, and what initial intervention would be appropriate?

    The nurse should suspect hypernatremia, likely due to water deficit in an elderly patient with limited water access. An appropriate initial intervention would be oral rehydration if possible, or IV volume replacement with isotonic fluids if the patient cannot take fluids orally.

75. Card 75

    How does the Renin-Angiotensin-Aldosterone System (RAAS) influence fluid and electrolyte balance, particularly in the context of sodium?

    The RAAS plays a crucial role in regulating blood pressure and fluid balance. When blood pressure or sodium levels are low, renin is released, leading to the production of angiotensin II. Angiotensin II stimulates aldosterone secretion from the adrenal cortex, which in turn promotes sodium and water reabsorption in the kidneys, helping to increase blood volume and sodium levels. Excess aldosterone can lead to hypernatremia.

76. Card 76

    How does parathyroid hormone (PTH) regulate calcium and phosphate levels in the body when serum calcium levels decrease?

    When serum calcium levels decrease, the parathyroid gland releases PTH. PTH acts to increase extracellular fluid (ECF) calcium by pulling calcium from bones and increasing its absorption. Concurrently, PTH increases phosphate excretion, demonstrating the inverse relationship between calcium and phosphate regulation.

77. Card 77

    DEFINITION: Distinguish between hypophosphataemia and hyperphosphataemia, including their primary causes.

    Hypophosphataemia is an abnormally low level of phosphate in the blood, often caused by increased renal excretion, hyperparathyroidism, or alcohol abuse. Hyperphosphataemia, conversely, is an abnormally high level of phosphate, typically resulting from impaired renal excretion, high phosphate intake (e.g., in infants fed cow's milk), or hypoparathyroidism.

78. Card 78

    A patient presents with muscle weakness, fatigue, and an increased risk of infection. Blood tests reveal abnormally low phosphate levels. What is a potential underlying cause for these symptoms, and how might it be managed?

    These symptoms are indicative of hypophosphataemia. Potential causes include increased renal excretion, hyperparathyroidism, or alcohol abuse. Management would focus on addressing the underlying cause, such as treating hyperparathyroidism or providing phosphate supplementation through diet or medication, while monitoring energy levels and oxygen utilization.

79. Card 79

    Which of the following is NOT a common cause of hypomagnesaemia? A) Alcoholism B) Diabetes C) Chronic renal insufficiency D) Malabsorption

    C) Chronic renal insufficiency. Chronic renal insufficiency is primarily associated with hypermagnesaemia due to impaired renal excretion, whereas alcoholism, diabetes, and malabsorption are common causes of hypomagnesaemia.

80. Card 80

    Explain the inverse relationship between calcium and phosphate and how calcitonin influences this balance.

    Calcium and phosphate have an inverse relationship, meaning that as one increases, the other tends to decrease. Calcitonin responds to increased serum calcium levels by keeping calcium in the bone and decreasing its absorption. This action also leads to a decrease in phosphorus excretion, further demonstrating the joint regulation of these two ions.

81. Card 81

    DEFINITION: Define hypermagnesaemia and list two major causes.

    Hypermagnesaemia is an abnormally high level of magnesium in the blood. It mainly occurs in patients with chronic renal insufficiency due to impaired excretion. Another major cause is the ingestion of large amounts of magnesium-containing compounds such as cathartics, magnesium citrate, or antacids.

82. Card 82

    A patient with chronic renal insufficiency is experiencing profound muscular weakness, areflexia, and sedation. What electrolyte imbalance is most likely present, and what immediate treatment might be considered?

    These symptoms strongly suggest hypermagnesaemia, which is common in patients with chronic renal insufficiency. Immediate treatments could include haemodialysis to remove excess magnesium from the blood or parenterally administered calcium salts to act as an antagonist to magnesium's effects.

83. Card 83

    Which electrolyte imbalance is most commonly associated with hyponatraemia and bicarbonate excess in metabolic alkalosis? A) Hyperchloraemia B) Hypochloraemia C) Hyperkalaemia D) Hypophosphataemia

    B) Hypochloraemia. Hypochloraemia is frequently associated with hyponatraemia and bicarbonate excess, particularly in the context of metabolic alkalosis, as chloride levels often decrease when bicarbonate levels rise to maintain charge neutrality.

84. Card 84

    Describe the physiological effects of magnesium on the nervous system and how these effects manifest in cases of hypomagnesaemia.

    Magnesium's physiological effects on the nervous system resemble those of calcium. In hypomagnesaemia, the lack of magnesium can lead to increased neuronal excitability. This manifests as symptoms like tremors, hyperactive deep reflexes, confusion, hallucinations, seizures, myoclonus, and muscle spasms.

85. Card 85

    DEFINITION: What is hypochloraemia, and what other electrolyte imbalances is it typically associated with?

    Hypochloraemia is an abnormally low level of chloride in the blood. It is typically associated with hyponatraemia, as chloride passively follows sodium, and with bicarbonate excess in metabolic alkalosis, where chloride levels may decrease as bicarbonate levels increase.

86. Card 86

    A patient is admitted with severe vomiting and diarrhea, leading to significant fluid loss. They also have a history of alcohol abuse. What electrolyte imbalance should the nurse be particularly vigilant for, and what are its characteristic signs?

    The nurse should be vigilant for hypomagnesaemia. Alcoholism, diarrhea, and fluid loss are all common causes. Characteristic signs include tremors, nausea, vomiting, hyperactive deep reflexes, confusion, seizures, and cardiac dysrhythmias.

87. Card 87

    Which of the following is a primary treatment for severe hypermagnesaemia? A) Oral magnesium supplements B) Furosemide administration C) Haemodialysis D) Increased dietary magnesium intake

    C) Haemodialysis. For severe hypermagnesaemia, especially in patients with renal insufficiency, haemodialysis is an effective treatment to return blood magnesium levels to normal by filtering out the excess.

88. Card 88

    How does the body's regulation of chloride contribute to extracellular fluid osmolarity and acid-base balance?

    Chloride is a major extracellular anion that significantly contributes to ECF osmolarity, influencing water movement between compartments. In terms of acid-base balance, chloride can be exchanged across cell membranes for bicarbonate, playing a role in maintaining the body's pH. For instance, in metabolic acidosis, chloride may increase as bicarbonate decreases.

89. Card 89

    DEFINITION: What is the role of phosphate in the body, beyond its inverse relationship with calcium?

    Beyond its inverse relationship with calcium, phosphate is an ion found in bones and plays crucial roles in energy production within tissues, primarily as a component of ATP. It is also essential for oxygen utilization and contributes significantly to the body's acid-base balance.

90. Card 90

    A patient with a history of heart failure and renal insufficiency develops severe hypercalcaemia. What inter-hospital treatment options might be considered to manage this condition?

    For severe hypercalcaemia in a patient with heart failure and renal insufficiency, inter-hospital treatment options include forced diuresis using normal saline and furosemide, and calcium-lowering drugs like thyrocalcitonin or steroids. Haemodialysis would also be a critical intervention given the co-existing heart failure and renal insufficiency to rapidly reduce calcium levels.

91. Card 91

    Which of the following is a symptom of hypercalcaemia? A) Hypotonia of muscles B) Hypoactive deep reflexes C) Increased energy levels D) Decreased risk of renal stones

    A) Hypotonia of muscles. Hypercalcaemia can lead to hypotonicity of muscles, altered mental status, renal stones, and cardiac dysrhythmias, among other symptoms. It does not typically cause hypoactive reflexes or increased energy.

92. Card 92

    Explain how vitamin D excess can contribute to hypercalcaemia and its potential impact on various body systems.

    Excessive vitamin D intake can lead to hypercalcaemia by increasing calcium absorption from the gastrointestinal tract and potentially enhancing calcium reabsorption in the kidneys. This elevated calcium can then be deposited in various body tissues and organ systems, including the gastrointestinal, central nervous, renal, neuromuscular, and cardiovascular systems, leading to a range of signs and symptoms.

93. Card 93

    DEFINITION: What is hyperchloraemia, and what other electrolyte imbalance is it closely associated with?

    Hyperchloraemia is an abnormally high level of chloride in the blood. It is closely associated with hypernatraemia, as chloride passively follows sodium to maintain electrical neutrality. It can also be linked to bicarbonate deficit in metabolic acidosis, as chloride is exchanged across the cell membrane for hydrogen.

94. Card 94

    A patient is diagnosed with hypoparathyroidism. Based on the inverse relationship between calcium and phosphate, what electrolyte imbalance would you anticipate regarding phosphate levels, and why?

    With hypoparathyroidism, one would anticipate hyperphosphataemia. This is because parathyroid hormone (PTH) normally increases phosphate excretion. Without sufficient PTH, phosphate excretion is impaired, leading to an accumulation of phosphate in the blood.

95. Card 95

    Which of the following conditions is a cause of hypophosphataemia? A) Hypoparathyroidism B) Impaired renal excretion C) Hyperglycaemia D) Tissue destruction

    C) Hyperglycaemia. Hyperglycaemia is listed as a cause of hypophosphataemia. Hypoparathyroidism and impaired renal excretion are causes of hyperphosphataemia, while tissue destruction can also lead to hyperphosphataemia.

96. Card 96

    DEFINITION: What is the primary role of aldosterone within the renin-angiotensin-aldosterone system concerning fluid and electrolyte balance?

    Aldosterone's primary role within the RAAS is to regulate sodium and potassium balance. It acts on the renal tubules to increase the reabsorption of sodium and water, while simultaneously increasing the excretion of potassium. This action helps to increase blood volume and blood pressure.

97. Card 97

    A patient is experiencing significant dehydration due to prolonged vomiting and diarrhea. Describe how the renin-angiotensin-aldosterone system would likely respond to this fluid loss to restore fluid balance.

    In response to dehydration and decreased blood volume, the kidneys would release renin. This initiates the RAAS cascade, leading to the production of angiotensin II, which causes vasoconstriction and stimulates the adrenal glands to release aldosterone. Aldosterone would then promote sodium and water reabsorption in the kidneys, helping to conserve fluid and restore blood volume and pressure.

98. Card 98

    Which hormone is released in response to increased serum calcium levels and acts to decrease calcium absorption and keep calcium in the bone? A) Parathyroid hormone B) Calcitonin C) Aldosterone D) Renin

    B) Calcitonin. Calcitonin is released from the thyroid gland in response to high serum calcium levels. It acts to lower calcium by inhibiting bone resorption and decreasing calcium absorption, effectively 'keeping' calcium in the bone.

99. Card 99

    Why are infants fed cow's milk at a higher risk for hyperphosphataemia compared to those fed breast milk or appropriate formula?

    Infants fed cow's milk are at a higher risk for hyperphosphataemia because cow's milk typically has a much higher phosphate content than breast milk or infant formula. An infant's immature kidneys may struggle to excrete this excess phosphate efficiently, leading to its accumulation in the blood.

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