Fluid And Electrolyte Imbalances - NCLEX Rn

1. A 31-year-old client with known diabetes insipidus is admitted for evaluation after stopping prescribed medication. Assessment: dry mucous membranes, tachycardia; urine output 4.5 L over 12 hours. Labs: sodium 157 mEq/L (135–145). Which laboratory value change requires IMMEDIATE intervention by the nurse?
   Answer: Sodium increases from 148 to 157 mEq/L This question tests clinical judgment in managing fluid and electrolyte imbalances. The key assessment finding is hypernatremia with high urine output and dehydration in untreated diabetes insipidus. The sodium increase from 148 to 157 mEq/L requires immediate intervention to prevent severe neurological effects. Minor increases in potassium, decreases in chloride, and increases in calcium are not urgent. The decision-making principle is to act on rising sodium in polyuric states with fluid and hormone therapy. Monitor for rapid changes. A transferable strategy is to resume medications promptly and hydrate in clients with known endocrine fluid disorders.
2. A 74-year-old client with chronic heart failure is seen in an acute care unit for worsening dyspnea and bilateral pitting edema after increasing fluid intake. Vital signs: blood pressure 168/92 mm Hg, heart rate 104/min, respiratory rate 26/min, oxygen saturation 90% on room air; crackles are heard in both lung bases. Labs: sodium 124 mEq/L (low), serum osmolality 265 mOsm/kg (low). What is the nurse's PRIORITY action for this client?
   Answer: Restrict fluids and elevate the head of the bed while applying oxygen as needed This question tests clinical judgment in managing fluid and electrolyte imbalances, specifically dilutional hyponatremia with fluid overload. The key assessment finding is hyponatremia (124 mEq/L) with signs of fluid volume excess including dyspnea, crackles, edema, and low serum osmolality. Restricting fluids and elevating the head of bed while applying oxygen (A) is the BEST choice because it addresses the immediate respiratory compromise from pulmonary edema while preventing further dilution of sodium. Starting hypotonic fluids (B) would worsen the hyponatremia and fluid overload; encouraging increased water intake (C) would dangerously worsen both problems; obtaining weight history (D) delays urgent intervention for respiratory distress. The decision-making principle is that dilutional hyponatremia with fluid overload requires fluid restriction and supportive respiratory care, not additional fluids. A transferable strategy is to recognize that hyponatremia in heart failure is usually dilutional, requiring fluid restriction rather than sodium replacement.
3. A 39-year-old client with suspected diabetes insipidus is admitted for evaluation after reporting polyuria and polydipsia. Vital signs: blood pressure 100/64 mm Hg, heart rate 112/min; skin is dry. Labs: sodium 154 mEq/L (high), serum osmolality 312 mOsm/kg (high), urine specific gravity 1.001 (low). What is the nurse's PRIORITY action for this client?
   Answer: Initiate seizure precautions and notify the provider of hypernatremia with dilute urine The priority is to prevent life-threatening neurological complications from hypernatremia. This client has high serum sodium with dilute urine, indicating diabetes insipidus and water loss. The nurse must initiate seizure precautions and notify the provider immediately. Restricting oral fluids would worsen hypernatremia because the client is already dehydrated from free water loss. Administering hypotonic IV fluids without an order is outside the nurse's scope, and rapid sodium correction risks cerebral edema. Encouraging increased sodium intake would further raise the already high sodium and osmolality. The key is recognizing the combination of hypernatremia with dilute urine as a medical emergency.
4. A 6-year-old child with gastroenteritis has diarrhea and abdominal cramping. Assessment: muscle weakness; vital signs: heart rate 124/min, blood pressure 92/56 mm Hg. Labs: potassium 3.1 mEq/L (3.5–5.0). What is the nurse's PRIORITY action?
   Answer: Administer potassium replacement as prescribed after verifying adequate urine output and continue hydration therapy This child has hypokalemia (potassium 3.1 mEq/L) with muscle weakness and tachycardia from ongoing GI losses. The priority is to replace potassium safely: confirm adequate urine output to ensure the kidneys can clear the potassium, then give replacement while continuing hydration. Intravenous calcium gluconate is used to protect the heart in hyperkalemia (or to treat acute hypocalcemia), not to correct a potassium deficit, so it does not address this child's problem. A low-potassium diet and withholding potassium-containing foods would worsen hypokalemia. Obtaining a stool culture and waiting for sensitivity results delays the needed potassium replacement and hydration; cultures may be indicated later, but they are not the priority in symptomatic hypokalemia. Choose the option that replaces potassium in a child with confirmed urine output.
5. A 69-year-old client with heart failure reports worsening orthopnea and has gained 2.7 kg (6 lb) in 5 days. Assessment: crackles throughout, 3+ edema; vital signs: blood pressure 172/94 mm Hg, heart rate 110/min, respiratory rate 28/min, oxygen saturation 88% on room air. Labs: sodium 124 mEq/L (135–145). What is the nurse's PRIORITY action?
   Answer: Apply supplemental oxygen and position the client upright to improve ventilation The priority is to support oxygenation and ventilation. This client has acute heart failure exacerbation with pulmonary edema: crackles, orthopnea, 3+ edema, and O2 saturation 88%. Upright positioning decreases venous return and improves lung mechanics, and supplemental oxygen raises arterial oxygenation while awaiting definitive diuretic therapy. Starting seizure precautions and giving hypotonic intravenous fluids is unsafe: hypotonic fluids would further lower serum sodium and increase fluid overload, and seizure precautions do not address the immediate respiratory threat. Encouraging increased free-water intake is also harmful because free water dilutes sodium further and worsens heart failure. Collecting a urine specimen to measure sodium before intervening delays the urgent oxygen supply and does not treat the current respiratory distress. Although hyponatremia needs evaluation and eventual management, oxygenation is the priority in this fluid-overloaded patient.
6. A 33-year-old client with suspected diabetes insipidus reports urinating 'every 30 minutes' and drinking large amounts of water. Vital signs: blood pressure 98/60 mm Hg, heart rate 116/min; urine output 350 mL/hr for 3 hours. Labs: sodium 154 mEq/L (135–145), urine specific gravity 1.003 (1.005–1.030). What is the nurse's PRIORITY action for this client?
   Answer: Begin strict intake and output measurement and notify the provider of suspected diabetes insipidus findings This question tests clinical judgment in managing fluid and electrolyte imbalances. The priority concern is hypernatremia with high urine output and low specific gravity, suggestive of diabetes insipidus. Beginning strict intake and output measurement and notifying the provider is the best choice to confirm diagnosis and initiate treatment like desmopressin. Restricting fluids would worsen dehydration; oral sodium tablets are contraindicated; potassium administration is not indicated without labs. The decision-making principle is to monitor fluid balance precisely in suspected diabetes insipidus to guide hormone replacement. Avoid rapid sodium correction to prevent complications. A transferable strategy is to use I&O trends to identify endocrine-related fluid imbalances early in polyuric clients.
7. An 82-year-old client with a history of dementia and chronic kidney disease stage 3 is brought to the emergency department from a nursing facility for acute confusion and lethargy after 2 days of poor oral intake. Assessment shows dry mucous membranes, poor skin turgor, and urine output 15 mL/hr; vital signs: blood pressure 92/54 mm Hg, heart rate 112/min, respiratory rate 18/min, temperature 37.1°C (98.8°F). Labs: sodium 156 mEq/L (135–145), blood urea nitrogen 38 mg/dL (7–20), creatinine 1.8 mg/dL (0.6–1.3). What is the nurse's PRIORITY action for this client?
   Answer: Start an intravenous infusion of 0.9% normal saline and monitor intake and output closely This client has hypovolemic hypernatremia: low blood pressure, tachycardia, oliguria, dry mucous membranes, and elevated BUN and creatinine after poor intake. The priority is to restore intravascular volume with an isotonic fluid. Starting 0.9% normal saline and monitoring intake and output addresses the volume deficit without causing a rapid drop in serum sodium, a key safety concern in this older adult with chronic kidney disease. Seizure precautions with hypertonic saline would add more sodium and worsen the hypernatremic state, so they are not the first action. Encouraging oral free water is unsafe and insufficient here: the client is confused, already volume-depleted, and unable to take fluids rapidly enough to restore perfusion. Giving furosemide intravenously promotes sodium and water loss, further depleting the already low intravascular volume and worsening hypotension and oliguria. Therefore, isotonic IV saline is the priority intervention.
8. A 79-year-old client with a history of hypertension is admitted for dehydration after 3 days of nausea and poor intake. Assessment: dry mucous membranes, tachycardia; vital signs: blood pressure 88/52 mm Hg, heart rate 120/min. Labs: sodium 155 mEq/L (135–145). What is the nurse's PRIORITY action?
   Answer: Initiate intravenous isotonic fluids per protocol and reassess blood pressure and urine output This question tests clinical judgment in managing fluid and electrolyte imbalances. The priority concern is hypovolemic hypernatremia with hypotension and tachycardia from poor intake. Initiating intravenous isotonic fluids is the best choice to restore volume and gradually correct sodium. Hypertonic saline would exacerbate hypernatremia; immediate large oral intake risks aspiration; delaying for weight overlooks urgency. The decision-making principle is to use isotonic solutions first in hypovolemic hypernatremia to stabilize hemodynamics. Follow with hypotonic fluids if needed, monitoring sodium closely. A transferable strategy is to assess volume status before choosing fluid type in elderly clients with nausea and electrolyte issues.
9. An 80-year-old client in a long-term care facility has had reduced fluid intake during a heat wave and now has confusion and weakness. Assessment: dry tongue, orthostatic hypotension; vital signs: lying blood pressure 110/70 mm Hg, standing blood pressure 92/60 mm Hg, heart rate 106/min. Labs: sodium 158 mEq/L (135–145), hematocrit 52% (36–46). Which laboratory value change requires IMMEDIATE intervention by the nurse?
   Answer: Sodium increases from 146 to 158 mEq/L This question tests clinical judgment in managing fluid and electrolyte imbalances. The key assessment finding is severe hypernatremia with orthostatic hypotension and elevated hematocrit, indicating dehydration. The sodium increase from 146 to 158 mEq/L requires immediate intervention to prevent neurological complications like seizures. The hematocrit increase reflects hemoconcentration but is secondary; minor potassium and chloride changes are not critical in this context. The decision-making principle is to address significant hypernatremia promptly with fluid replacement to avoid brain shrinkage. Monitoring should include serial labs and vital signs. A transferable strategy is to prioritize correction of extreme electrolyte shifts in elderly clients during heat-related dehydration scenarios.
10. A 76-year-old client with heart failure (ejection fraction 30%) presents to an urgent care clinic with 3 days of worsening dyspnea and ankle swelling. Assessment: crackles at lung bases, 2+ pitting edema, weight gain of 3.2 kg (7 lb) in 1 week; vital signs: blood pressure 168/92 mm Hg, heart rate 104/min, respiratory rate 26/min, oxygen saturation 90% on room air. Labs: sodium 128 mEq/L (135–145), serum osmolality 268 mOsm/kg (275–295). What is the nurse's PRIORITY action for this client?
    Answer: Place the client in high-Fowler position and apply supplemental oxygen per protocol The client's oxygen saturation of 90%, crackles, and tachypnea indicate acute respiratory compromise from fluid overload. The priority is to place the client in high-Fowler position and support oxygenation. Encouraging increased oral water intake would add more free water to a client who is already fluid overloaded and hyponatremic, making both problems worse. Administering desmopressin promotes water retention and reduced urine water loss, the opposite of the diuresis this client needs, and it does not correct the sodium imbalance. Obtaining a 24-hour urine collection is a diagnostic step, but using it as the first action delays the urgent respiratory support. The correct priority action is therefore the high-Fowler position with supplemental oxygen.
11. A 6-year-old child with acute gastroenteritis has had vomiting and watery diarrhea for 2 days and is lethargic with decreased tears. Vital signs: heart rate 132/min, respiratory rate 24/min, blood pressure 88/50 mm Hg; capillary refill 4 seconds. Labs: potassium 2.9 mEq/L (low), bicarbonate 18 mEq/L (low). What is the nurse's PRIORITY action for this child?
    Answer: Initiate isotonic intravenous fluids and anticipate potassium replacement as ordered This question tests clinical judgment in managing fluid and electrolyte imbalances, specifically hypovolemic shock with hypokalemia in a pediatric patient. The key assessment finding is severe dehydration with hypotension, tachycardia, delayed capillary refill, and critical hypokalemia (2.9 mEq/L). Initiating isotonic IV fluids and anticipating potassium replacement (B) is the BEST choice because it addresses the immediate circulatory collapse while preparing for electrolyte correction once urine output is established. Antidiarrheal medication (A) doesn't address the life-threatening hypovolemia; clear liquids only (C) is insufficient for severe dehydration with shock; fluid restriction (D) would be fatal in hypovolemic shock. The decision-making principle is that pediatric hypovolemic shock requires rapid isotonic fluid resuscitation, with potassium replacement after establishing adequate perfusion and urine output. A transferable strategy is to prioritize circulatory stabilization in pediatric dehydration before correcting electrolyte imbalances, as potassium replacement requires functioning kidneys.
12. A 3-year-old child is seen in the emergency department for 2 days of vomiting and watery diarrhea. Assessment: lethargy, sunken eyes, dry mucous membranes, capillary refill 4 seconds; vital signs: heart rate 148/min, respiratory rate 28/min, blood pressure 86/50 mm Hg, temperature 37.4°C (99.3°F). Labs: potassium 3.0 mEq/L (3.5–5.0), bicarbonate 18 mEq/L (22–28). What is the nurse's PRIORITY action for this child?
    Answer: Administer a rapid isotonic intravenous fluid bolus per pediatric protocol and reassess perfusion. The child's tachycardia, low blood pressure, prolonged capillary refill, sunken eyes, and lethargy indicate hypovolemic shock from dehydration. The priority is to restore perfusion with a rapid isotonic intravenous fluid bolus and reassess. Oral potassium replacement before fluid resuscitation focuses on the low potassium while the child is still volume depleted; fluid replacement must come first. Restricting oral and intravenous fluids will worsen the dehydration and delay recovery of the child's perfusion. Insulin with dextrose drives potassium into cells and is used for hyperkalemia, not for the hypokalemia present here; giving it would make the potassium level even lower. The correct sequence is to treat the life-threatening hypovolemia first, then address any electrolyte imbalances if still needed.
13. A 29-year-old client with a history of traumatic brain injury is admitted to an acute care unit with polyuria and intense thirst. Intake and output for the last 6 hours: intake 600 mL, urine output 2200 mL; vital signs: blood pressure 102/64 mm Hg, heart rate 110/min, respiratory rate 18/min. Labs: sodium 152 mEq/L (135–145), urine specific gravity 1.002 (1.005–1.030). Which symptom indicates a need for FURTHER assessment?
    Answer: New onset confusion and restlessness This question tests clinical judgment in managing fluid and electrolyte imbalances. The key assessment finding is hypernatremia with polyuria and low urine specific gravity, suggesting diabetes insipidus. New onset confusion and restlessness indicates a need for further assessment as it may signal worsening hypernatremia or neurological complications. Dry mucous membranes and frequent drinking are expected in dehydration; urine output exceeding intake and low specific gravity are consistent with the condition and do not require additional scrutiny beyond standard monitoring. The decision-making principle is to monitor for neurological changes in hypernatremia as they can progress to seizures or coma. Fluid replacement should be guided by sodium levels and volume status. A transferable strategy is to frequently reassess mental status in clients with polyuria and electrolyte shifts to detect early deterioration.
14. A 70-year-old client with heart failure is admitted for fluid volume excess and is receiving a loop diuretic. The client has bilateral crackles and 3+ pitting edema. Vital signs: blood pressure 156/88 mm Hg, heart rate 98/min, respiratory rate 24/min, oxygen saturation 92% on 2 L/min nasal cannula. Labs: sodium 126 mEq/L (low), potassium 4.1 mEq/L. Which symptom indicates a need for FURTHER assessment?
    Answer: New onset confusion and headache This question tests clinical judgment in managing fluid and electrolyte imbalances, specifically recognizing cerebral symptoms of severe hyponatremia. The key assessment finding is new onset confusion and headache in a patient with hyponatremia (126 mEq/L) and fluid overload. New onset confusion and headache (A) is the BEST choice for further assessment because these are signs of cerebral edema from severe hyponatremia requiring immediate intervention. Bilateral ankle edema (B), mild exertional dyspnea (C), and nocturia (D) are expected findings in heart failure with fluid overload and don't indicate acute deterioration. The decision-making principle is that neurological symptoms in hyponatremia indicate cerebral edema requiring urgent treatment to prevent seizures or coma. A transferable strategy is to prioritize neurological assessment in hyponatremic patients, as mental status changes herald life-threatening complications.
15. A 74-year-old client with heart failure is receiving intravenous furosemide and now reports dizziness and headache. Assessment: crackles improved, but client appears drowsy; vital signs: blood pressure 136/78 mm Hg, heart rate 88/min. Labs: sodium 122 mEq/L (135–145). Which laboratory value change requires IMMEDIATE intervention by the nurse?
    Answer: Sodium decreases from 130 to 122 mEq/L This question tests clinical judgment in managing fluid and electrolyte imbalances. The key assessment finding is hyponatremia with drowsiness and headache in a heart failure client receiving diuretics. The sodium decrease from 130 to 122 mEq/L requires immediate intervention to prevent seizures or coma. Decreases in BUN, chloride, and creatinine are not critical and may reflect dilution or improved renal function. The decision-making principle is to monitor for rapid sodium drops during diuresis and adjust therapy to avoid severe hyponatremia. Fluid restriction and hypertonic saline may be needed cautiously. A transferable strategy is to track serial electrolytes during diuretic therapy in heart failure to intervene on worsening imbalances promptly.
16. A 62-year-old client is 1 day post-operative after bowel resection and has a nasogastric tube to low suction. The client reports weakness and muscle cramps. Vital signs: blood pressure 124/76 mm Hg, heart rate 102/min. Labs: potassium 3.0 mEq/L (low), chloride 94 mEq/L (low). What is the nurse's PRIORITY action for this client?
    Answer: Administer potassium replacement and assess for dysrhythmias This question tests clinical judgment in managing fluid and electrolyte imbalances, specifically hypokalemia from gastric losses. The key assessment finding is hypokalemia (3.0 mEq/L) with hypochloremia from nasogastric suction, presenting with weakness and muscle cramps. Administering potassium replacement and assessing for dysrhythmias (B) is the BEST choice because hypokalemia increases risk of cardiac dysrhythmias and must be corrected promptly. Holding opioids (A) doesn't address the electrolyte emergency; sodium bicarbonate (C) is inappropriate as there's no acidosis indicated; encouraging water intake (D) won't correct potassium or chloride deficits. The decision-making principle is that gastric losses cause hypokalemic, hypochloremic metabolic alkalosis requiring potassium and chloride replacement with cardiac monitoring. A transferable strategy is to anticipate electrolyte losses with nasogastric suction and monitor for signs of hypokalemia including weakness, cramps, and dysrhythmias.
17. A 78-year-old client with dehydration is admitted after being found confused at home. Assessment: dry mucous membranes, tachycardia; vital signs: blood pressure 90/56 mm Hg, heart rate 118/min. Labs: sodium 154 mEq/L (135–145). What is the nurse's PRIORITY action?
    Answer: Administer intravenous 0.9% normal saline and monitor for improvement in perfusion and mental status The findings—sodium 154 mEq/L, hypotension, tachycardia, dry mucous membranes, and confusion—indicate hypovolemic hypernatremia from water loss exceeding sodium loss. The immediate threat is inadequate perfusion, so the nurse should restore intravascular volume with an isotonic fluid. Intravenous 0.9% normal saline expands the vascular space without rapidly lowering serum sodium, and monitoring perfusion and mental status evaluates whether resuscitation is working. Delaying fluids for a head CT puts a hypotensive client at risk of further underperfusion; imaging can follow stabilization. Furosemide is a loop diuretic that promotes additional fluid and electrolyte loss, which worsens hypovolemia and does not correct hypernatremia. Hypertonic saline would raise serum sodium further, and there is no sodium deficit to correct; it is not indicated for this hypernatremic dehydration. Reassess vital signs, urine output, and neurologic status, and avoid overcorrection.
18. A 46-year-old client is 2 days post-op after bowel resection with nasogastric suction and reports tingling and new muscle cramps. Vital signs: blood pressure 124/76 mm Hg, heart rate 72/min, respiratory rate 18/min. Labs: potassium 3.1 mEq/L (3.5–5.0), sodium 140 mEq/L (135–145). What is the nurse's PRIORITY action for this client?
    Answer: Administer intravenous potassium replacement as prescribed and place the client on cardiac monitoring This question tests clinical judgment in managing fluid and electrolyte imbalances. The key assessment finding is hypokalemia likely from nasogastric suction losses, presenting with tingling and cramps. Administering intravenous potassium replacement with cardiac monitoring is the best choice to correct the imbalance and prevent arrhythmias. Hypotonic fluids are unnecessary with normal sodium; ambulation does not address hypokalemia; discontinuing suction may be needed but is not priority over replacement. The decision-making principle is to replace potassium safely in post-operative clients with GI losses while monitoring cardiac effects. Ensure adequate renal function before administration. A transferable strategy is to anticipate electrolyte shifts from suctioning and intervene early with replacement therapy in surgical clients.
19. A 62-year-old client is 24 hours post-op after prostate surgery and has been receiving intravenous fluids and has had intermittent vomiting. Assessment: muscle weakness and ileus; vital signs: blood pressure 132/78 mm Hg, heart rate 64/min. Labs: potassium 3.0 mEq/L (3.5–5.0). Which symptom indicates a need for FURTHER assessment?
    Answer: New onset irregular heart rhythm on telemetry With a potassium of 3.0 mEq/L, the priority is to recognize hypokalemia-related cardiac irritability. New onset irregular heart rhythm on telemetry is the finding that signals a possible arrhythmia and requires further assessment, including an ECG and evaluation of the rhythm. Intermittent mild muscle cramps in the calves are an expected manifestation of hypokalemia, so they do not indicate a new complication. Decreased bowel sounds consistent with the known ileus only restates the ileus already documented in the assessment, not a change requiring further workup. Generalized fatigue that improves with rest and repositioning is nonspecific and improving, rather than an acute change suggesting an arrhythmia. In hypokalemia, prioritize new rhythm changes over expected neuromuscular and gastrointestinal findings.
20. A 58-year-old client is 12 hours post-abdominal surgery and reports generalized weakness and new palpitations. Vital signs: blood pressure 118/70 mm Hg, heart rate 116/min, respiratory rate 20/min, oxygen saturation 96% on room air; bowel sounds are hypoactive. Labs: potassium 2.8 mEq/L (low), magnesium 1.6 mg/dL (low-normal). Telemetry shows frequent premature ventricular contractions. What is the nurse's PRIORITY action for this client?
    Answer: Administer potassium replacement per protocol and maintain continuous cardiac monitoring This question tests clinical judgment in managing fluid and electrolyte imbalances, specifically critical hypokalemia with cardiac manifestations. The key assessment finding is hypokalemia (2.8 mEq/L) with cardiac dysrhythmias (PVCs) and associated hypomagnesemia. Administering potassium replacement per protocol with continuous cardiac monitoring (A) is the BEST choice because it addresses the life-threatening dysrhythmias while ensuring safe replacement. Encouraging ambulation (B) is unsafe with active dysrhythmias and severe hypokalemia; discontinuing telemetry (C) removes critical monitoring during a cardiac emergency; calcium gluconate (D) is used for hyperkalemia, not hypokalemia. The decision-making principle is that hypokalemia with cardiac manifestations requires immediate potassium replacement with continuous monitoring due to risk of ventricular fibrillation. A transferable strategy is to prioritize cardiac safety in severe hypokalemia, remembering that magnesium must also be replaced for effective potassium correction.

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