A nurse is caring for a patient with hypertension who has been receiving oral hydrochlorothiazide for the past week. Which assessment finding should be the nurse's highest priority?

Severe hypokalemia (K+ 2.8 mEq/L) is life-threatening due to high risk of cardiac arrhythmias from furosemide-induced potassium loss, making it the highest priority. Other findings like hypotension or decreased urine output are less immediately dangerous.

Core Nursing Explanation Key Concept Analysis: This question tests the nurse's ability to prioritize patient assessment findings based on the Maslow's hierarchy of needs and the ABC (Airway, Breathing, Circulation) framework, specifically in the context of a patient taking a diuretic. The core theme is recognizing a life-threatening electrolyte imbalance that directly threatens cardiac and neuromuscular function. While hydrochlorothiazide (HCTZ) is a thiazide diuretic known for causing hypokalemia (low potassium), the scenario presents a critical finding of hyperkalemia (high potassium). This is a less common but serious adverse effect that requires immediate intervention. Answer Rationale: The correct answer is option ③. A serum potassium level of 5.8 mEq/L is hyperkalemic (normal range: 3.5-5.0 mEq/L). Hyperkalemia can cause life-threatening cardiac arrhythmias, including ventricular fibrillation and asystole. The accompanying symptom of new onset muscle weakness is a classic sign of hyperkalemia affecting neuromuscular function, indicating the condition is progressing. This combination of a dangerously high lab value and a new, significant symptom makes this the highest priority finding, as it poses an immediate threat to life (circulation and neuromuscular stability). Distractor Analysis: Watch out for confusion! Option ①: A blood pressure of 90/60 mmHg with tachycardia (110 bpm) indicates hypotension, likely from volume depletion due to the diuretic. While important and requiring monitoring/intervention (e.g., holding the medication, fluid administration), it is not typically as immediately life-threatening as severe hyperkalemia-induced cardiac instability. The tachycardia is a compensatory mechanism.
Watch out for confusion! Option ②: A significant decrease in urine output is a concern for acute kidney injury (AKI) or severe dehydration. This requires investigation and intervention but, in isolation, does not indicate the same level of imminent physiological collapse as a critical electrolyte imbalance affecting the heart.
Watch out for confusion! Option ④: Weight loss of 3 kg in 24 hours is a significant indicator of fluid loss, which is an expected effect of diuretic therapy. While it confirms the drug's effectiveness and requires monitoring for over-diuresis, it is not an acute, life-threatening finding on its own. Related Concepts: This question highlights the importance of not making assumptions. While HCTZ commonly causes hypokalemia, nurses must assess the actual data presented. Hyperkalemia in this context could be due to other factors like renal impairment (the kidney's inability to excrete potassium), concurrent use of potassium-sparing medications, or excessive potassium intake. The priority is always the finding that poses the greatest immediate threat to physiological stability. Concept Summary

Concept	Key Points
Hydrochlorothiazide (HCTZ)	Thiazide diuretic. Common side effects: Hypokalemia, hyponatremia, hyperglycemia, hyperuricemia, orthostatic hypotension.
Hyperkalemia (K+ >5.0 mEq/L)	Life-threatening due to cardiac arrhythmias. Symptoms: Muscle weakness, paresthesia, nausea, ECG changes (peaked T waves, widened QRS).
Nursing Priority Setting	Use ABCs (Airway, Breathing, Circulation) and Maslow's hierarchy. Life-threatening conditions (e.g., arrhythmias, severe electrolyte imbalances) take precedence.
Diuretic Monitoring	Monitor for electrolyte imbalances (K+, Na+), fluid status (I&O, daily weights), renal function (BUN, creatinine), and blood pressure.

Side-by-Side Comparison!

Assessment Finding	Potential Cause with HCTZ	Immediate Threat Level	Priority Nursing Action
K+ 5.8 mEq/L with weakness	Hyperkalemia (Renal impairment, K+ supplements)	HIGH (Cardiac arrest risk)	Notify provider STAT, obtain ECG, prepare for emergency treatment (e.g., calcium gluconate, insulin/glucose, kayexalate).
BP 90/60, HR 110	Hypotension/Volume depletion (Over-diuresis)	MODERATE-HIGH	Assess for dizziness/falls, hold diuretic, consider IV fluids per order, monitor closely.
Decreased Urine Output	Acute Kidney Injury (AKI) or Severe Dehydration	MODERATE	Assess hydration, review medications, notify provider, monitor BUN/Cr.

Anatomy, Physiology & Pharmacology Points

• Potassium Physiology: Essential for normal nerve impulse conduction and muscle contraction, especially cardiac muscle. The heart is exquisitely sensitive to potassium levels.
• HCTZ Mechanism: Inhibits sodium reabsorption in the distal convoluted tubule of the nephron. Increased sodium delivery to the collecting duct promotes potassium excretion (via the Na+/K+ exchange), typically leading to hypokalemia.
• Hyperkalemia Patho: Elevated extracellular potassium decreases the resting membrane potential of cardiac cells, making them more excitable initially, then leading to slowed conduction and eventual arrest.

Memory Tips

• H for HCTZ, H for Hypo-K (usually): Remember HCTZ usually causes Hypokalemia. But always check the lab value!
• Hyper-K Hurts the Heart: Hyperkalemia's biggest danger is cardiac arrhythmias.
• Weakness with High K: New muscle weakness + high potassium level = red flag for immediate action.

High-Frequency NCLEX Topics This integrates several high-yield NCLEX areas: medication side effects, electrolyte imbalances, priority setting, and laboratory value interpretation. The NCLEX loves to test your ability to recognize abnormal findings that indicate a life-threatening complication versus expected or less urgent side effects of a drug. Watch Out for Question Variations!

• Instead of asking for the "highest priority finding," it could ask: "The nurse should notify the provider immediately for which finding?" or "Which finding indicates a potentially life-threatening complication of hydrochlorothiazide therapy?"
• The drug could change (e.g., furosemide causing hypokalemia, spironolactone causing hyperkalemia), testing your knowledge of specific drug effects.
• It could present an ECG strip showing peaked T waves and ask for the corresponding lab value and priority intervention.

Nursing Clinical Practice Guide Clinical Scenario: You are the nurse on a medical-surgical unit. Mr. Johnson, a 68-year-old with a history of hypertension and chronic kidney disease (CKD) Stage 3, was started on hydrochlorothiazide 25 mg daily one week ago. During your afternoon assessment, he complains of new-onset fatigue and his legs feel "heavy and weak" when he tries to walk. You review his morning labs. Nursing Intervention Strategy: 1. Immediate Assessment: Upon seeing the potassium of 5.8 mEq/L and hearing the complaint of weakness, your first action is to assess the patient's cardiac status. Check an ECG (Electrocardiogram) immediately at the bedside if available. Look for signs of hyperkalemia: peaked T waves, widened QRS complex, or loss of P waves. 2. Communication & Collaboration: Notify the primary care provider or rapid response team STAT with the following information: "Mr. Johnson, on HCTZ, has a potassium of 5.8 with new muscle weakness. His ECG shows [report findings]. Requesting immediate orders." 3. Safety & Monitoring: Place the patient on continuous cardiac monitoring. Ensure IV access is patent. Hold the next dose of hydrochlorothiazide. Monitor vital signs and neurological status closely. 4. Patient Education: Once the acute situation is managed, educate the patient on signs of electrolyte imbalance (muscle cramps, weakness, palpitations) and the importance of follow-up labs. Review his diet, as he may have been consuming high-potassium foods (e.g., bananas, oranges, potatoes) assuming he needed them, which could have contributed to the problem. Patient Safety and Precautions: - Key Point! In patients with renal impairment, thiazide diuretics can become ineffective and increase the risk of electrolyte disturbances, including hyperkalemia, due to reduced renal excretion. - Always assess renal function (BUN, creatinine) before and during diuretic therapy. - Do not assume the side effect profile. Assess the individual patient's response and lab data. Nursing Procedure & Medication Flow Managing Hyperkalemia: Expected Provider Orders & Nursing Role 1. Cardioprotection: Administer IV calcium gluconate or chloride as ordered. This stabilizes the cardiac cell membrane but does not lower potassium. Monitor ECG for normalization. 2. Shift Potassium into Cells: Administer IV regular insulin with dextrose (e.g., 10 units regular insulin in 50 mL of D50W). This drives potassium into cells, lowering serum levels within 30-60 minutes. Monitor blood glucose closely to prevent hypoglycemia. 3. Enhance Potassium Excretion: Administer a loop diuretic like furosemide (if patient is volume overloaded) or a potassium-binding resin like sodium polystyrene sulfonate (Kayexalate) orally or as a retention enema. 4. Dialysis: For severe, refractory hyperkalemia or in patients with end-stage renal disease (ESRD), hemodialysis may be required. A Word from Your Senior Nurse "Great catch! This question is a perfect example of why we never practice on autopilot. Yes, HCTZ 'usually' causes low potassium, but your patient is giving you different data. In the real world, a patient's comorbidities (like CKD), diet, and other meds change the picture entirely. Your most powerful tool is critical thinking—connecting the dots between the drug, the patient's history, the lab values, and their symptoms. When you see a lab value that's critically out of range paired with a new symptom, your internal alarm bells should ring. That's the clinical judgment the NCLEX is testing, and more importantly, that's what keeps your patients safe."