Don't Be Blue

A 21-year-old woman presented with a sore throat, low-grade fever, body aches, swollen glands, and generalized malaise for three days. The patient said her symptoms had worsened over the past day. She denied any difficulty breathing but endorsed pain and difficulty swallowing.   Her initial vital signs were blood pressure 132/84 mm Hg, heart rate 113 bpm, respiratory rate 22 bpm, temperature 100.4°F, and pulse oximetry 100% on room air. She was diagnosed with a peritonsillar abscess, and the EP applied a topical anesthetic to the area prior to draining it. During the procedure, the patient’s pulse oximetry dropped to 85%, heart rate increased to 124, and respiratory rate increased to 28. The patient appeared cyanotic, and was diagnosed with methemoglobinemia from benzocaine spray.   Credit Nursing Health Assessment, Lippincott Williams & Wilkins, 2014.   What are five toxicologic causes of methemoglobinemia? n Topical anesthetics (benzocaine, prilocaine, lidocaine) n Dapsone (systemic and topical use have been reported to cause methemoglobinemia) n Organic and inorganic nitrates and nitrites (well water that has been contaminated by nitrites due to runoff from fertilized fields, as well as nitrofuran antibiotics, poppers/amyl nitrate) n Antimalarials (chloroquine, primaquine) n Industrial or household products (Aniline dyes, naphthalene (moth balls)   The patient’s methemoglobin (MetHb) level was 32%, and she was given methylene blue 1 mg/kg IV with resolution o...
Source: The Tox Cave - Category: Emergency Medicine Tags: Blog Posts Source Type: blogs