Case Report
Nosocomial Methemoglobinemia Resulting from Self-Administration of Benzocaine Spray
Table 1
Expected signs and symptoms for a given percentage methemoglobin level assuming normal starting hemoglobin [
6,
7].
| Percentage methemoglobin | Expected symptoms |
| 10% | None | 10–20% | Peripheral and central cyanosis | 20–30% | Anxiety, tachycardia, lightheadedness, and headache | 30–50% | Confusion, dizziness, fatigue, tachypnea, and worsening tachycardia | 50–70% | Acidosis, arrhythmia, seizures, and coma | 70% | Death |
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