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Fluid & Electrolyte NCLEX Practice Questions

Medically reviewed by Douglas Carollo, MSN, APRN, FNP-BC Updated September 2026 10 practice questions

Ten free fluids, electrolytes, and IV therapy NCLEX practice questions with full rationales — IV fluid tonicity, fluid volume deficit vs excess, blood compatibility, and the potassium, sodium, calcium, and magnesium imbalances behind many priority questions, including IV potassium safety and safe hyponatremia correction. Answer each one, then reveal the correct answer and see why every option is right or wrong. No sign-up needed to practice here.

High-Yield Fluids, Electrolytes & IV Therapy Review

IV fluids are grouped by tonicity, and matching the fluid to the clinical picture is a core skill. Isotonic fluids expand circulating volume, making 0.9% normal saline and lactated Ringer the go-to fluids for fluid volume deficit, hypovolemia, and blood loss. Lactated Ringer is taught as isotonic, but its calculated osmolarity (273 mOsm/L) is slightly below plasma, so trauma guidelines advise avoiding it in severe head injury. D5W is a special case: it is isotonic in the bag but acts effectively hypotonic once the dextrose is metabolized, leaving free water behind, so it is used for free-water replacement or as a drug diluent, not to resuscitate hypovolemia or blood loss, and it is avoided when intracranial pressure is a concern. Hypotonic fluids (0.45% and 0.225% normal saline) shift water into cells to treat cellular dehydration and hypernatremia, but they can worsen cerebral edema and are used cautiously or avoided in head injury and increased intracranial pressure. Hypertonic saline (3% and higher) pulls water out of cells and is reserved for severe symptomatic hyponatremia and cerebral edema; it is given in small, controlled amounts on a pump with close monitoring for fluid overload. Other dextrose-containing fluids differ in purpose: D10W treats hypoglycemia, while D5NS and D5LR are maintenance or replacement fluids that behave closer to isotonic once the dextrose is metabolized, and none of these treat hyponatremia or cerebral edema. And only 0.9% normal saline is compatible with blood products.

Volume status drives assessment. Fluid volume deficit presents with tachycardia, hypotension and orthostasis, poor skin turgor, dry mucous membranes, oliguria with dark concentrated urine, weight loss, and rising hematocrit and BUN; treatment is isotonic IV fluid. Fluid volume excess shows a bounding pulse, hypertension, jugular vein distention, crackles and dyspnea, dependent edema, and rapid weight gain; treatment includes diuretics, sodium and fluid restriction, semi-Fowler positioning, and daily weights.

Know your IV complications. Infiltration is cool, swollen, and pale with sluggish or absent flow and no blood return; you stop the infusion, remove the catheter, and elevate the limb. Phlebitis is red, warm, and tender with a palpable cord along the vein; you discontinue the IV and apply a warm compress. For more on peripheral sites and central lines, work through the IV therapy and central line practice questions.

Sodium problems are water problems, and they show up in the brain. Normal serum sodium is roughly 135-145 mEq/L. In SIADH, retained water dilutes the sodium, so the usual treatment is fluid restriction. Severe symptomatic hyponatremia, with seizures or coma, is treated with small, controlled boluses of 3% saline (about 100 mL) to raise the sodium 4-6 mEq/L and relieve cerebral edema; after that, correction slows. Current guidance limits the rise to about 8 mEq/L in the first 24 hours, because overly rapid correction can cause osmotic demyelination syndrome, with dysarthria, dysphagia, and paralysis that may appear days later. Give 3% saline on an infusion pump, check the sodium often, watch for fluid overload, and report a rise faster than prescribed.

Potassium problems show up in the heart and muscles. Normal potassium is about 3.5-5.0 mEq/L. Hypokalemia causes weakness, cramps, and ileus, with flattened T waves, ST depression, and prominent U waves on the ECG. IV potassium chloride is always diluted and never given by IV push; it runs on a pump, usually no faster than 10 mEq/hr, after you confirm the client is making urine. Hyperkalemia starts with peaked T waves, then PR prolongation, loss of P waves, QRS widening, and a sine-wave pattern that can end in ventricular fibrillation or asystole. When the ECG changes, think stabilize, shift, remove: IV calcium gluconate protects the heart within minutes, insulin with dextrose shifts potassium into the cells, and binders, loop diuretics, or dialysis remove it.

Low calcium and low magnesium both make nerves and muscles overexcitable, with brisk reflexes, tetany, and seizures. Low calcium also causes tingling around the mouth and fingertips, muscle cramps, the Chvostek and Trousseau signs, laryngospasm, and a prolonged QT interval; watch for it after thyroid surgery. High calcium does the opposite: constipation, weakness, confusion, polyuria, kidney stones, and a shortened QT interval. Hypomagnesemia (below about 1.8 mg/dL) is common with alcohol use disorder, diuretics, and chronic diarrhea, and it keeps potassium and calcium from correcting until magnesium is replaced. Hypermagnesemia, usually seen with kidney failure, causes loss of deep tendon reflexes, hypotension, and respiratory depression; IV calcium gluconate reverses these effects temporarily.

Fluids, Electrolytes & IV Therapy NCLEX Practice Questions

Question 1 · IV fluid tonicity – isotonic

A client arrives in the emergency department after a motor vehicle collision with an estimated 1,500 mL blood loss, blood pressure 84/52 mm Hg, and heart rate 122/min. Which IV solution should the nurse anticipate administering to expand this client's vascular volume?

  • A 0.9% sodium chloride (normal saline)
  • B 3% sodium chloride
  • C Dextrose 10% in water
  • D 0.45% sodium chloride (half-normal saline)
Show answer & rationale
Correct answer: A
This client is in hypovolemic shock from acute blood loss and needs an isotonic fluid that stays in the vascular space to restore circulating volume and perfusion. Normal saline (0.9% sodium chloride) is isotonic, expands the intravascular compartment, and is the standard resuscitation crystalloid; it is also the only fluid compatible with blood products, which this client will likely need. Half-normal saline (0.45% sodium chloride) is hypotonic and shifts water into the cells rather than expanding the vascular volume, so it would worsen hypotension and is used for cellular dehydration, not shock. The 3% sodium chloride is hypertonic and is reserved for severe symptomatic hyponatremia or cerebral edema; giving it here would draw water into the vessels too aggressively without addressing the underlying volume loss and risks fluid overload. Dextrose 10% in water is hypertonic in the bag, provides free water once the dextrose is metabolized, and is used for glucose or fluid needs, not for resuscitating a hemorrhaging client. Clinical pearl: for hypovolemia and blood loss, think isotonic first, specifically normal saline or lactated Ringer, because isotonic fluids fill the tank without shifting water into or out of the cells. A quick memory aid is that iso means equal, so the fluid stays where you put it: in the vessels where a bleeding, hypotensive client needs it most.
Question 2 · IV fluid tonicity – hypotonic caution

A client with a traumatic brain injury has signs of increasing intracranial pressure. Which prescribed IV solution should the nurse question because it poses the greatest risk of worsening cerebral edema?

  • A Lactated Ringer solution
  • B 3% sodium chloride prescribed for symptomatic hyponatremia
  • C 0.45% sodium chloride
  • D 0.9% sodium chloride
Show answer & rationale
Correct answer: C
Hypotonic fluids drive water out of the vascular space and into the cells, including brain cells, which can worsen cerebral edema and further raise intracranial pressure. For a client with a head injury and rising ICP, 0.45% sodium chloride (half-normal saline) is hypotonic and should be questioned because it can increase brain swelling. Normal saline (0.9% sodium chloride) is isotonic and is commonly used in neurologic clients because it does not shift free water into brain cells. Lactated Ringer is taught as isotonic, but its calculated osmolarity (273 mOsm/L) is slightly below plasma, and the 2023 European trauma guideline recommends avoiding it in severe head injury; it is still much closer to plasma than half-normal saline, so it is not the greatest risk here. Hypertonic 3% saline actually pulls water out of swollen brain cells and is sometimes used deliberately to reduce cerebral edema, so it is not the order to question in this scenario. Clinical pearl: in any client at risk for increased ICP, avoid hypotonic fluids and remember that even D5W becomes effectively hypotonic once the dextrose is metabolized, leaving free water behind. A useful memory aid: hypotonic swells the cell, and the last thing a swollen brain needs is more water moving in. When ICP is the concern, isotonic maintains and hypertonic can pull water out, but hypotonic should raise a red flag.
Question 3 · Sodium – hyponatremia treated with 3% saline

A client with syndrome of inappropriate antidiuretic hormone (SIADH) had a seizure with a serum sodium of 114 mEq/L and is receiving 3% sodium chloride. Six hours later, the client is alert and the serum sodium is 126 mEq/L. Which action should the nurse take?

  • A Continue the infusion because the sodium is still below normal
  • B Notify the provider about the rapid rise in the serum sodium
  • C Increase the infusion rate so the sodium normalizes sooner
  • D Document the value as an expected response to therapy
Show answer & rationale
Correct answer: B
The sodium has risen 12 mEq/L in 6 hours. Current guidance limits the rise to about 8 mEq/L in the first 24 hours, so this client has already passed the full-day limit and is at risk for osmotic demyelination syndrome. The nurse reports the result now so the provider can stop the hypertonic saline and, if needed, give hypotonic fluid such as D5W with desmopressin to bring the sodium back down. Continuing the infusion because the value is still below normal is wrong: in severe symptomatic hyponatremia, 3% saline is meant to produce a small early rise of about 4-6 mEq/L that relieves cerebral edema and stops seizures, not to return the sodium to normal. Increasing the rate would speed the overcorrection and add to the risk of demyelination. Documenting the value as an expected response misses the danger, because a 12 mEq/L jump in 6 hours is overcorrection, not a routine result. Clinical pearl: signs of osmotic demyelination, such as dysarthria, dysphagia, and weakness progressing to paralysis, can appear days after the sodium was corrected, so a client who looks well now can still be harmed. Once the client is stable, SIADH is managed with fluid restriction, not extra free water.
Question 4 · Potassium – IV replacement for hypokalemia

A client with a serum potassium of 2.9 mEq/L is prescribed IV potassium chloride through a peripheral IV line. Which actions should the nurse take? Select all that apply.

  • A Give the dose by IV push over 5 minutes
  • B Use an infusion pump and do not exceed 10 mEq/hr
  • C Confirm adequate urine output before starting
  • D Hold the dose because the client reports leg cramps
  • E Assess the IV site for burning, pain, and phlebitis
  • F Monitor the ECG for flattened T waves and U waves
Show answer & rationale
Correct answer: B, C, E, F
IV potassium chloride is a high-alert medication because too much, too fast can stop the heart. Using an infusion pump and keeping the rate at or below 10 mEq/hr is correct; product labeling calls for a calibrated infusion device and a usual maximum of 10 mEq/hr when the potassium is above 2.5 mEq/L, with faster rates reserved for urgent cases on continuous cardiac monitoring. Confirming adequate urine output is correct because the kidneys excrete most potassium, and IV potassium can cause life-threatening hyperkalemia in a client with renal failure. Assessing the site for burning, pain, and phlebitis is correct because potassium irritates veins, especially peripheral ones, and the client may need a slower rate or a different line. Monitoring the ECG for flattened T waves and U waves is correct because a potassium of 2.9 mEq/L can produce these changes and dysrhythmias, and the rhythm shows how the client responds to replacement. Giving the dose by IV push is wrong and potentially fatal: direct injection of potassium chloride can cause cardiac arrest, so it is always diluted and infused. Holding the dose for leg cramps is wrong because cramps and muscle weakness are symptoms of hypokalemia, which makes replacement more urgent, not less. Clinical pearl: if the potassium stays low despite replacement, check the magnesium level, because low magnesium keeps the kidneys wasting potassium.
Question 5 · Potassium – hyperkalemia priority

A client with acute kidney injury has a serum potassium of 7.1 mEq/L, and the cardiac monitor shows peaked T waves and a widening QRS complex. The provider prescribes the following medications. Which should the nurse administer first?

  • A Sodium zirconium cyclosilicate orally
  • B Regular insulin IV with dextrose
  • C Calcium gluconate IV
  • D Furosemide IV
Show answer & rationale
Correct answer: C
Peaked T waves with a widening QRS mean the high potassium is already affecting cardiac conduction, and the next steps can be loss of P waves, a sine-wave pattern, ventricular fibrillation, or asystole. IV calcium gluconate comes first because it stabilizes the cardiac cell membrane and protects against dysrhythmias within minutes. It does not lower the potassium, and its effect lasts only about 20 to 30 minutes, so treatment to lower the potassium must follow. Regular insulin with dextrose is the next priority: insulin shifts potassium into the cells, the dextrose prevents hypoglycemia, and the effect peaks in about an hour, which is too slow to be the first protection for a heart that is already showing changes. Sodium zirconium cyclosilicate binds potassium in the gut but lowers the level over several hours, so binders are not emergency treatment. Furosemide increases renal potassium excretion only when the kidneys respond and the client is not volume depleted, which is unreliable in acute kidney injury. Clinical pearl: think stabilize, shift, remove. Calcium protects the heart, insulin with dextrose shifts potassium into the cells, and binders, diuretics, or hemodialysis remove it from the body. Hemodialysis is started promptly when medical treatment fails, especially in kidney injury.
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Question 6 · Blood and IV compatibility

The nurse is preparing to administer a unit of packed red blood cells. Which IV solution should the nurse use to prime the tubing and run with the blood product?

  • A 0.45% sodium chloride
  • B Lactated Ringer solution
  • C Dextrose 5% in water
  • D 0.9% sodium chloride
Show answer & rationale
Correct answer: D
Only 0.9% sodium chloride (normal saline) is compatible with blood products and should be used to prime the tubing and run alongside the transfusion. Normal saline is isotonic and contains no calcium or glucose, so it will not interact with the citrate anticoagulant in the blood or damage the red cells. Lactated Ringer contains calcium, which can overcome the citrate anticoagulant and promote clotting within the tubing, so it is not used with blood. Dextrose 5% in water is hypotonic once the dextrose is metabolized and causes red blood cells to swell and hemolyze, making it unsafe with a transfusion. Half-normal saline (0.45% sodium chloride) is hypotonic and likewise causes red cell hemolysis, so it is not compatible with blood products. Clinical pearl: for transfusions, saline is the only safe line. Memory aid: normal saline and blood are the perfect pair because saline neither clots nor bursts the cells. Always use a Y-type blood administration set primed with 0.9% normal saline, verify the product and client identity with a second qualified staff member, take baseline vital signs, and stay with the client for the first 15 minutes when a reaction is most likely. Any dextrose or calcium-containing solution can ruin the unit, so keep those away from the transfusion tubing.
Question 7 · Calcium – hypocalcemia after thyroidectomy

The nurse is caring for a client on the first day after a total thyroidectomy. Which findings should the nurse recognize as signs of hypocalcemia? Select all that apply.

  • A Tingling around the mouth and in the fingertips
  • B Diminished deep tendon reflexes in both legs
  • C A shortened QT interval noted on the cardiac monitor
  • D Carpal spasm during blood pressure cuff inflation
  • E Facial twitching when the facial nerve is tapped
  • F Constipation with increasing lethargy
Show answer & rationale
Correct answer: A, D, E
Total thyroidectomy can injure or remove the parathyroid glands, and the resulting drop in parathyroid hormone lowers the serum calcium; temporary hypoparathyroidism is common after thyroid surgery. Low calcium makes nerves and muscles overexcitable. Tingling around the mouth and in the fingertips is correct because paresthesias of the lips and fingers are a sensory sign of hypocalcemia. Carpal spasm during blood pressure cuff inflation is correct: this is a positive Trousseau sign, elicited by inflating the cuff above systolic pressure for about 3 minutes. Facial twitching when the facial nerve is tapped just in front of the ear is correct: this is a positive Chvostek sign. Diminished deep tendon reflexes are wrong because hypocalcemia causes brisk, hyperactive reflexes; diminished or absent reflexes fit the opposite pattern, as in magnesium excess. A shortened QT interval is wrong because hypocalcemia prolongs the QT interval, while a short QT points to hypercalcemia. Constipation with increasing lethargy is also a hypercalcemia pattern, not a sign of low calcium. Clinical pearl: report these findings promptly and keep IV calcium gluconate available, because hypocalcemia can progress to laryngospasm and seizures. Low magnesium can also cause low calcium, so a calcium level that will not correct may need magnesium replacement as well.
Question 8 · Fluid volume deficit assessment

The nurse is assessing a client with suspected fluid volume deficit (hypovolemia). Which findings support this diagnosis? Select all that apply.

  • A Bounding, full peripheral pulses
  • B Poor skin turgor with tenting
  • C Dark, concentrated urine with low output
  • D Dry, sticky mucous membranes
  • E Heart rate 118/min (tachycardia)
  • F Jugular vein distention
Show answer & rationale
Correct answer: B, C, D, E
Fluid volume deficit means the vascular space is underfilled, so the body compensates and shows signs of dehydration. Tachycardia occurs as the heart speeds up to maintain cardiac output with less circulating volume. Poor skin turgor with tenting reflects the loss of interstitial fluid and reduced skin elasticity. Dry, sticky mucous membranes indicate inadequate fluid to keep tissues moist. Dark, concentrated urine with low output shows the kidneys conserving water, and urine specific gravity rises as the body holds on to every drop. Bounding, full peripheral pulses are incorrect because they signal fluid volume excess, not deficit; a hypovolemic client typically has weak, thready pulses. Jugular vein distention is also a sign of fluid overload and elevated venous pressure, so it does not fit a deficit; a hypovolemic client usually has flat neck veins. Clinical pearl: in deficit, everything trends dry and fast, so expect tachycardia, hypotension and orthostasis, dry membranes, poor turgor, oliguria with concentrated urine, weight loss, and rising hematocrit and BUN. Memory aid: less water in the tank means a faster, weaker pump and thirstier, drier tissues. Treatment centers on replacing volume with isotonic IV fluids such as normal saline or lactated Ringer while monitoring vital signs, daily weights, and urine output for response.
Question 9 · Fluid volume excess assessment

The nurse is monitoring a client with heart failure for fluid volume excess. Which assessment findings are consistent with hypervolemia? Select all that apply.

  • A Rapid weight gain over 2 days
  • B Crackles auscultated in the lung bases
  • C Dependent edema in the ankles and feet
  • D Flat neck veins when supine
  • E Hypotension with orthostatic changes
  • F Bounding peripheral pulses
Show answer & rationale
Correct answer: A, B, C, F
Fluid volume excess means too much fluid is circulating and backing up into the tissues and lungs. Crackles in the lung bases occur as excess fluid moves into the alveoli, producing pulmonary congestion. Dependent edema in the ankles and feet reflects fluid shifting into the interstitial space in gravity-dependent areas. Rapid weight gain over a short period is one of the most sensitive indicators of fluid retention, since roughly 1 liter of retained fluid equals about 1 kilogram, or 2.2 pounds. Bounding peripheral pulses result from the increased circulating volume and higher vascular pressure. Flat neck veins are incorrect because overload causes jugular vein distention, not flat veins; flat veins suggest deficit. Hypotension with orthostatic changes is also incorrect because it points to volume deficit; a hypervolemic client usually shows hypertension. Clinical pearl: in excess, everything trends full and wet, so expect a bounding pulse, hypertension, jugular vein distention, crackles and dyspnea, dependent edema, and rapid weight gain. Memory aid: too much water in the tank means a strong, bounding pump and fluid spilling into lungs and tissues. Nursing management includes diuretics, sodium and fluid restriction, semi-Fowler positioning to ease breathing, daily weights at the same time on the same scale, and strict intake and output monitoring to track the client's response to therapy.
Question 10 · Electrolytes – hypokalemia that will not correct

A client with alcohol use disorder has received IV potassium chloride for 2 days, but the serum potassium remains 3.1 mEq/L. The serum magnesium is 1.1 mg/dL, and the client has hyperactive deep tendon reflexes. Which prescription should the nurse anticipate?

  • A Magnesium sulfate IV
  • B Calcium gluconate IV
  • C Furosemide IV
  • D Spironolactone orally
Show answer & rationale
Correct answer: A
A magnesium of 1.1 mg/dL is well below normal (hypomagnesemia is a level under about 1.8 mg/dL), and alcohol use disorder is a common cause because of poor intake and increased renal loss. Magnesium sulfate IV is correct because low magnesium makes hypokalemia refractory: when intracellular magnesium falls, the kidney's potassium secretion channels lose their normal brake, so potassium keeps leaking into the urine no matter how much is replaced. The potassium will not stay up until the magnesium is repleted. Hyperactive reflexes fit hypomagnesemia, which increases neuromuscular excitability. Calcium gluconate is wrong because it treats symptomatic hypocalcemia or protects the heart in hyperkalemia; it does not replace magnesium or stop the potassium loss. Furosemide is wrong because loop diuretics increase urinary loss of both potassium and magnesium and would deepen both deficits. Spironolactone is wrong because, although it spares potassium, it does not replace the missing magnesium that is driving the potassium wasting. Clinical pearl: magnesium is cleared by the kidneys, so during IV replacement the nurse checks deep tendon reflexes, respiratory rate, and urine output and follows serum magnesium levels. Loss of reflexes and respiratory depression signal magnesium excess, and IV calcium gluconate reverses these effects temporarily.

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Fluids, Electrolytes & IV Therapy NCLEX FAQ

What is the difference between isotonic, hypotonic, and hypertonic IV fluids?

Tonicity describes how a fluid moves water relative to the cells. Isotonic fluids such as 0.9% normal saline and lactated Ringer have about the same concentration as blood, so they expand circulating volume, making them ideal for fluid volume deficit, hypovolemia, and blood loss. D5W is isotonic in the bag but acts hypotonic once the dextrose is metabolized, leaving free water behind, so it is used for free-water replacement or as a diluent rather than to treat hypovolemia. Hypotonic fluids (0.45% or 0.225% normal saline) are more dilute and shift water into cells to treat cellular dehydration and hypernatremia, but they can worsen cerebral edema and are used cautiously in increased ICP. Hypertonic saline (3% and higher) is more concentrated and pulls water out of cells; it is reserved for severe symptomatic hyponatremia and cerebral edema and is given slowly with close monitoring for fluid overload. Other dextrose fluids serve different roles: D10W treats hypoglycemia, and D5NS or D5LR are maintenance and replacement fluids.

How do I tell infiltration and phlebitis apart on the NCLEX?

Focus on temperature and color. Infiltration happens when the catheter dislodges and fluid leaks into the tissue, producing a cool, pale, swollen, taut site with sluggish or absent flow and no blood return. The nursing action is to stop the infusion, remove the catheter, and elevate the extremity. Phlebitis is inflammation of the vein, producing redness, warmth, tenderness, and a palpable cord along the vein. The action is to discontinue the IV and apply a warm compress. A quick memory aid: cool and colorless means infiltration (elevate), while warm and red with a cord means phlebitis (warm compress). Both require removing the current IV and restarting in a new site.

Which IV fluid can be given with blood, and why does it matter?

Only 0.9% sodium chloride (normal saline) is compatible with blood products. Normal saline is isotonic and free of calcium and glucose, so it will not clot the line or damage red cells. Lactated Ringer contains calcium, which can overcome the citrate anticoagulant in stored blood and cause clotting. Dextrose solutions such as D5W act hypotonically once the dextrose is metabolized and cause red cells to swell and hemolyze. Always prime the blood administration set with normal saline, verify the product and client with a second qualified staff member, obtain baseline vital signs, and stay with the client during the first 15 minutes when reactions are most likely.

Why is D5W avoided in clients with increased intracranial pressure?

D5W is isotonic while it sits in the bag, but the body quickly metabolizes the dextrose, leaving only free water behind, so the solution behaves as effectively hypotonic. That free water shifts into cells, including swollen brain cells, and can raise intracranial pressure and worsen cerebral edema. For a client with a head injury or increased ICP, isotonic normal saline is generally preferred for maintenance because it does not add free water to the brain, and hypertonic saline may even be used deliberately to pull water out of edematous tissue. Think of D5W as a hidden hypotonic hazard when the brain is at risk, and question it if it is ordered for a client with increased ICP.

What are the safety rules for giving IV potassium chloride?

Potassium chloride is never given by IV push or undiluted, because direct injection can cause fatal cardiac arrest. It is diluted, run on an infusion pump, and usually given no faster than 10 mEq/hr; faster rates are reserved for urgent cases with continuous cardiac monitoring. Confirm the client is making urine before you start, because the kidneys excrete potassium and IV potassium can cause life-threatening hyperkalemia in renal failure. Check the IV site often, since potassium irritates veins and can cause pain and phlebitis. If the potassium will not rise despite replacement, check the magnesium level: low magnesium keeps the kidneys wasting potassium until it is corrected.

How do I remember the signs of calcium and magnesium imbalances?

Low levels make nerves and muscles overexcitable, and high levels slow them down. Low calcium and low magnesium both cause brisk reflexes, tetany, and seizures, and low magnesium often adds a tremor. Low calcium also causes tingling around the mouth and fingertips, a positive Chvostek sign (facial twitching when the facial nerve is tapped), a positive Trousseau sign (carpal spasm when a blood pressure cuff is inflated), laryngospasm, and a prolonged QT interval. High calcium causes constipation, weakness, confusion, polyuria, kidney stones, and a shortened QT interval. High magnesium causes loss of deep tendon reflexes, hypotension, and respiratory depression. IV calcium gluconate treats symptomatic hypocalcemia and temporarily reverses magnesium toxicity.

Sources

Sources checked September 2026.

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