Brain on Sodium
A client's serum sodium is 128 mEq/L. What electrolyte imbalance does this indicate?
Hyponatremia
Rationale: Normal serum sodium is approximately 135–145 mEq/L. A sodium of 128 is below normal. Hyponatremia can cause neurologic manifestations because decreased serum osmolality causes water to move into cells, including brain cells.
A client's potassium level is 3.0 mEq/L. What imbalance does this indicate?
Hypokalemia
Rationale: Normal potassium is approximately 3.5–5.0 mEq/L. A potassium of 3.0 is low and can affect neuromuscular function and, most importantly, cardiac conduction.
A client's total serum calcium is 7.2 mg/dL. What imbalance is present?
Hypocalcemia
Rationale: Normal total calcium is approximately 8.5–10.5 mg/dL. Low calcium increases neuromuscular excitability and can also affect cardiac conduction.
A client's magnesium level is 1.1 mg/dL. What imbalance is present?
Hypomagnesemia
Rationale: Normal magnesium is approximately 1.7–2.2 mg/dL. A low magnesium level can cause neuromuscular hyperexcitability and cardiac electrical instability.
Which client should the nurse assess first?
C. Potassium 6.7 mEq/L with ECG changes
Rationale: Severe hyperkalemia with ECG changes represents an immediate threat to cardiac conduction and can progress rapidly to fatal dysrhythmias or cardiac arrest. The other findings require attention but are not as immediately life-threatening.
A client with severe hyponatremia develops headache, confusion, and increasing lethargy. What complication is the nurse most concerned about?
Cerebral edema and progression to seizures
Rationale: Severe hyponatremia decreases serum osmolality, causing water to shift into brain cells. Cerebral swelling can produce headache, confusion, decreased level of consciousness, seizures, and potentially life-threatening neurologic deterioration.
A client with significant hypokalemia is at greatest risk for which potentially life-threatening complication?
Cardiac dysrhythmias
Rationale: Potassium is essential for normal myocardial electrical activity. Hypokalemia can alter cardiac repolarization and increase the risk for dysrhythmias, particularly when the potassium level is significantly decreased or the client has other cardiac risk factors.
A client with hypocalcemia reports tingling around the mouth and muscle spasms. What is causing these manifestations?
Increased neuromuscular excitability
Rationale: Calcium helps stabilize neuronal and muscle-cell membranes. Low calcium increases neuromuscular excitability, producing paresthesias, muscle cramps, spasms, tetany, and potentially seizures
Which assessment finding would the nurse expect with hypomagnesemia?
Tremors and hyperactive deep-tendon reflexes
Rationale: Low magnesium increases neuromuscular excitability. Manifestations can include tremors, muscle cramps, hyperreflexia, weakness, tetany, seizures, and dysrhythmias.
A client receives potassium replacement. The potassium level returns to the expected range. Which finding provides the best evidence that treatment has been effective?
Improved muscle strength and a stable cardiac rhythm
Rationale: Treatment effectiveness should be evaluated using both laboratory data and clinical response. Correction of potassium should improve manifestations such as weakness and reduce cardiac electrical instability. The nurse should continue monitoring because potassium can shift again.
A client has a sodium level of 122 mEq/L and is confused and unsteady when walking. What is the nurse's priority nursing action?
Implement safety and seizure precautions and closely monitor neurologic status.
Rationale: Severe hyponatremia places the client at risk for neurologic deterioration and seizures. Safety precautions help prevent injury while the underlying sodium imbalance is treated. Frequent neurologic assessment is essential for detecting worsening cerebral effects.
The provider prescribes IV potassium chloride for a client with hypokalemia. Which action is essential for safe administration?
Dilute the potassium and administer it using an infusion pump; never administer potassium IV push.
Rationale: IV potassium is a high-alert medication. Concentrated potassium can cause fatal cardiac dysrhythmias if administered too rapidly. It must be appropriately diluted and infused at a controlled rate according to institutional policy.
The nurse inflates a blood pressure cuff on a client with suspected hypocalcemia. The client's hand develops a painful carpal spasm. What is this finding called?
Trousseau sign
Rationale: Trousseau sign is carpal spasm produced by occluding the arm with a blood pressure cuff. It indicates increased neuromuscular excitability and is associated with hypocalcemia.
Why is severe hypomagnesemia particularly concerning in a client who develops a cardiac dysrhythmia?
Magnesium is important for normal neuromuscular and cardiac electrical activity, and severe deficiency can increase dysrhythmia risk.
Rationale: Magnesium influences cardiac conduction and interacts with other electrolytes, particularly potassium and calcium. Severe hypomagnesemia can contribute to dangerous dysrhythmias and may make other electrolyte abnormalities more difficult to correct.
A client with severe hypocalcemia develops muscle spasms and difficulty speaking. What assessment becomes the priority?
Airway and respiratory status
Rationale: Severe hypocalcemia can cause laryngospasm and respiratory muscle involvement. Although the electrolyte imbalance must be treated, the immediate nursing priority is identifying and managing an airway or breathing threat.
A client has a sodium level of 154 mEq/L, intense thirst, dry mucous membranes, and concentrated urine. What condition is most consistent with these findings?
Hypernatremia associated with fluid volume deficit/dehydration
Rationale: Hypernatremia commonly occurs when water loss exceeds sodium loss. Thirst, dry mucous membranes, and concentrated urine indicate inadequate body water. The nurse should assess fluid status, neurologic status, intake/output, and the underlying cause.
A client with hypokalemia reports muscle weakness and palpitations. Which ECG finding would the nurse anticipate?
Prominent U waves
Rationale: Hypokalemia commonly causes flattened T waves, ST-segment depression, and prominent U waves. Severe hypokalemia can produce serious ventricular dysrhythmias.
A client with hypercalcemia develops weakness, constipation, and flank pain. Which complication should the nurse suspect?
Renal calculi (kidney stones)
Rationale: Hypercalcemia can decrease renal concentrating ability and contribute to calcium-containing kidney stones. Other manifestations include weakness, constipation, lethargy, polyuria, dehydration, and dysrhythmias.
A client receiving IV magnesium develops hypotension, decreased deep-tendon reflexes, and respiratory depression. What should the nurse suspect?
Hypermagnesemia/magnesium toxicity
Rationale: Excess magnesium depresses neuromuscular and cardiac function. Toxicity can cause diminished or absent reflexes, hypotension, bradycardia, muscle weakness, respiratory depression, and potentially cardiac arrest.
Which client requires immediate intervention?
B. Potassium 6.9 mEq/L with widened QRS complexes
Rationale: A widened QRS indicates worsening cardiac conduction impairment from severe hyperkalemia. This is an immediate life-threatening emergency requiring continuous cardiac monitoring and rapid treatment to stabilize the myocardium and lower the serum potassium.
A client is being treated for significant hypernatremia. Which finding best indicates that treatment is working?
Neurologic status and hydration improve while the serum sodium gradually moves toward the desired range.
Rationale: Effective treatment should improve the manifestations of hypernatremia while correcting the sodium imbalance safely. Chronic or significant hypernatremia generally requires gradual correction because overly rapid correction can cause cerebral edema and neurologic complications.
A client's potassium is 6.8 mEq/L and the ECG shows tall, peaked T waves. What should the nurse do?
Recognize this as a life-threatening hyperkalemia emergency, maintain continuous cardiac monitoring, and prepare for immediate treatment.
Rationale: Severe hyperkalemia can rapidly progress from peaked T waves to PR prolongation, QRS widening, ventricular dysrhythmias, and cardiac arrest. ECG changes indicate that the elevated potassium is already affecting cardiac conduction and requires urgent intervention.
A client with severe hypercalcemia is lethargic and dehydrated. Which intervention would the nurse anticipate as an important component of treatment?
IV fluid replacement as prescribed
Rationale: Hydration increases renal perfusion and promotes urinary calcium excretion. Depending on the cause and severity, additional treatment may include medications such as calcitonin or bisphosphonates. The nurse must monitor fluid status, renal function, calcium levels, and cardiac status.
A client develops severe magnesium toxicity with respiratory depression. Which medication may be prescribed to counteract the effects of magnesium?
IV calcium gluconate
Rationale: IV calcium can antagonize magnesium's effects on the heart and neuromuscular system and is used in significant magnesium toxicity. The nurse must also support airway and breathing, monitor cardiac status, and address the underlying magnesium excess.
A client with chronic kidney disease has a potassium level of 6.5 mEq/L and peaked T waves. The provider prescribes IV calcium gluconate, insulin with dextrose, and a potassium-lowering therapy. Explain the purpose of each treatment.
Rationale: These treatments address different parts of the emergency. Calcium protects the heart but does not lower serum potassium. Insulin shifts potassium intracellularly but does not remove it from the body. A potassium-removing intervention provides more definitive correction. Continuous cardiac monitoring and frequent reassessment are essential.