Digitalis Toxicity Clinical Presentation

Updated: Jan 04, 2017
  • Author: Vinod Patel, MD; Chief Editor: Jeffrey N Rottman, MD  more...
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Presentation

History

Most cases of pediatric digitalis poisoning are unintentional ingestions; thus, a good social history with emphasis on available medications and the extent of home childproofing is necessary.

In patients who have been taking digoxin, the recent addition of a new drug to their regimen should be noted. Drugs that can elevate the digoxin level include the following:

  • Verapamil

  • Diltiazem

  • Erythromycin

  • Tetracycline

  • Paroxetine

In contrast, rifampin increases digitalis metabolism by enzymatic stimulation and thereby decreases the digoxin level.

Extracardiac symptoms

Central nervous system (CNS) symptoms of digitalis toxicity include the following:

  • Drowsiness

  • Lethargy

  • Fatigue

  • Neuralgia

  • Headache

  • Dizziness

  • Confusion or giddiness

  • Hallucinations

  • Seizures (rare)

  • Paresthesias and neuropathic pain

Visual aberration often is an early indication of digitalis toxicity. Yellow-green distortion is most common, but red, brown, blue, and white distortions also occur. Drug intoxication also may cause the following:

  • Snowy vision

  • Photophobia

  • Photopsia

  • Decreased visual acuity

  • Yellow halos around lights (xanthopsia)

  • Transient amblyopia or scotomata

Gastrointestinal (GI) symptoms in acute or chronic toxicity include the following:

  • Anorexia

  • Weight loss

  • Failure to thrive (in pediatric patients)

  • Nausea

  • Vomiting

  • Abdominal pain

  • Diarrhea

  • Mesenteric ischemia (a rare complication of rapid IV infusion)

Cardiac symptoms

Cardiac symptoms include the following:

  • Palpitations

  • Shortness of breath

  • Syncope

  • Swelling of lower extremities

  • Bradycardia

  • Hypotension

  • Dyspnea

Next:

Physical Examination

Patients can have an asymptomatic period of from several minutes to several hours after the oral ingestion of a single toxic dose. Clinical signs may be subtle or obvious, depending on the severity of toxicity. Acute toxicity is rarely subtle, whereas chronic toxicity may be difficult to diagnose. Nausea, vomiting, and drowsiness are among the most common extracardiac manifestations. Visual changes usually affect patients with chronic toxicity. Emphasis should be placed on the vital signs and the neurologic and cardiovascular findings.

The patient's mentation may change according to the severity of digoxin toxicity, as well as associated comorbid conditions. Although the patient may note visual changes, the pupils are spared and objective findings are few. Drug-induced fever does not occur.

The pulse may be irregular if the patient has atrial fibrillation or arrhythmia arising from the digoxin toxicity itself. Hypotension may be observed if the patient has chronic heart failure or dehydration secondary to decreased oral intake. Neck findings include increased jugular venous pressure.

Hemodynamic instability is related directly to the presence of a dysrhythmia or to acute exacerbation of chronic heart failure (CHF). Associated cardiomegaly may be identified. Cardiovascular findings on physical examination relate to the severity of CHF, dysrhythmias, or hemodynamic instability.

The respiratory rate is sometimes increased. Basal crepitations are associated with CHF. Although GI symptoms are common, the abdominal examination is usually nonspecific. An enlarged liver secondary to CHF (ie, hepatic congestion) may be palpated. Hepatojugular reflux is present. Pedal edema is noted if the patient has renal failure or decompensated CHF.

Neurologic findings are related to changes in sensorium or mental status. Lateralizing findings usually indicate another disease process.

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