# A nurse is caring for a patient receiving digoxin therapy. Which assessment finding would be the most important indicator that the patient may be experiencing digoxin toxicity?

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## 문제

A nurse is caring for a patient receiving digoxin therapy. Which assessment finding would be the most important indicator that the patient may be experiencing digoxin toxicity?

## 보기

1. Heart rate of 58 beats per minute with regular rhythm
2. Patient reports seeing yellow halos around lights and nausea **✔ 정답**
3. Serum potassium level of 5.2 mEq/L
4. Blood pressure of 110/70 mmHg

**정답: 2**

## 해설

Visual disturbances like yellow halos with nausea are classic early signs of digoxin toxicity requiring immediate intervention. Other options represent expected findings or normal values manageable with standard monitoring.

## 심화 해설

Understanding Digoxin Toxicity

Digoxin is a cardiac glycoside with a narrow therapeutic index, meaning the difference between a therapeutic dose and a toxic dose is very small [1][4]. Its primary uses are for rate control in atrial fibrillation and managing heart failure [1]. The drug is predominantly excreted by the kidneys, which makes patients with impaired renal function, such as those with chronic kidney disease (CKD) or acute kidney injury, highly susceptible to toxicity due to reduced clearance and tissue accumulation [3][4]. Toxicity can occur even when serum digoxin concentrations are within the traditionally accepted therapeutic range, as highlighted by recent case reports [1].

Analysis of Assessment Findings

When monitoring a patient on digoxin, the nurse must systematically evaluate all findings, but some are more specific and critical indicators of toxicity than others.

- **Option 1 (Heart rate of 58 bpm):** While bradycardia is a classic cardiac sign of digoxin toxicity and a heart rate below 60 beats per minute is the standard parameter for holding the dose, a rate of 58 bpm with a regular rhythm is a borderline finding. It is a sensitive but less specific early warning sign when considered in isolation. The nurse should hold the medication and assess further, but this finding alone is not the most definitive indicator of toxicity [2].

- **Option 2 (Yellow halos around lights and nausea):** This combination represents the most specific and classic non-cardiac indicators of digoxin toxicity. Xanthopsia (seeing yellow halos or a yellow-green tint) and other visual disturbances like photopsia (seeing sparkles of light) are well-documented neuro-ophthalmic effects [2][4]. Nausea is a hallmark gastrointestinal symptom of toxicity, often preceding more severe effects [4]. The simultaneous presence of both visual and GI symptoms is a high-priority red flag that strongly suggests toxicity, making this the most important assessment finding.

- **Option 3 (Serum potassium of 5.2 mEq/L):** A potassium level of 5.2 mEq/L is a mild hyperkalemia. While digoxin toxicity can cause hyperkalemia due to inhibition of the Na+/K+-ATPase pump, this finding is a potential consequence, not a primary diagnostic indicator. Furthermore, hypokalemia is a more common risk factor that potentiates digoxin's effects and predisposes a patient to toxicity [2]. This lab value is nonspecific and could have many other causes.

- **Option 4 (Blood pressure of 110/70 mmHg):** A blood pressure of 110/70 mmHg is a normotensive reading. While digoxin toxicity can lead to cardiogenic shock and hypotension in severe cases, this finding is not an indicator of toxicity [4].

The patient's report of yellow halos and nausea directly corresponds to the sensory disturbances and gastrointestinal symptoms documented in digoxin toxicity cases, including rare presentations like phantosmia and photopsia [2]. This subjective data is a critical and specific cue that must be recognized and acted upon immediately to prevent progression to life-threatening arrhythmias [1][4].

References (research sources)

- [1]Digoxin toxicity with therapeutic serum digoxin concentrations.Research articleGraafsma J, Cimic N, Dijkman M, Gresnigt FMJ, Mitrovic D, Smit C. (2025) · DOI: 10.1016/j.toxrep.2025.102079

- [2]Floral phantosmia and bradycardia: A unique case of digoxin toxicity in an elderly patient.Research articleKasa M, Elezi B, Sinamati E, Spahia N, Rroji M. (2025) · DOI: 10.4103/tjem.tjem_275_24

- [3]Digoxin Toxicity in Renal Failure: Resolution With Plasma Exchange After Fab Therapy Failure.Research articleWilliams JM, Reddy P. (2025) · DOI: 10.7759/cureus.96841

- [4]Dietary lifestyle changes unexpectedly causing digoxin intoxication with cardiogenic shock: a grand round case report.Case reportGerritsma AM, Hagdorn QAJ, Geurkink TH, Groothuis JG, van Ofwegen-Hanekamp CEE, Lagas JS. (2025) · DOI: 10.1093/ehjcr/ytaf352

## 임상 시나리오

Recognizing Digoxin ToxicityKey Assessment Findings for Early Intervention
The most specific non-cardiac indicators of digoxin toxicity are visual disturbances (e.g., yellow halos, blurred vision) and gastrointestinal symptoms (e.g., nausea, vomiting, anorexia). These often precede cardiac arrhythmias.

Cardiac signs like bradycardia (heart rate < 60 bpm) are common but less specific. A rate of 58 bpm is a borderline finding that requires holding the dose and further assessment, but it is not the definitive sign of toxicity.

CautionToxicity can occur even with a "therapeutic" serum digoxin level, especially in patients with renal impairment or hypokalemia. Always correlate lab values with clinical assessment findings.

## 핵심 개념

- **Digoxin Toxicity** — Digoxin toxicity. A syndrome that occurs when the blood concentration of digoxin, a cardiac glycoside with a narrow therapeutic range, rises excessively. Early symptoms include visual disturbances (xanthopsia) and gastrointestinal symptoms (nausea, vomiting), while later stages can lead to life-threatening arrhythmias.
- **Xanthopsia** — Xanthopsia. A visual disturbance where objects appear yellow. It is a typical early symptom of digoxin toxicity, described as a "yellow halo around lights."
- **Cardiac Glycoside** — Cardiac glycosides. The drug class to which digoxin belongs. It increases myocardial contractility (positive inotropic effect) and reduces heart rate by inhibiting atrioventricular node conduction.
- **Therapeutic Window** — Therapeutic window. The range of blood concentration at which a drug exerts its therapeutic effect. Digoxin has a very narrow therapeutic window (0.5-2.0 ng/mL), so the therapeutic concentration and toxic concentration are close.
- **Hypokalemia** — Hypokalemia. A condition where serum potassium levels fall below normal (

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