Less than 1 min later, the patient converted to a narrow complex rhythm at an improved rate (QRS 80 ms, QTc 507 at 106 BPM, Figure 2), and her blood pressure improved to 135/92 mm Hg. She received a 120 mL bolus of 20% IV lipid emulsion (Intralipid®) based upon a dosing weight of 80 kg.
A repeat EKG was unchanged from the immediately previous one. Thirty-five minutes later, the patient became hypotensive with a systolic blood pressure of 90/54 mmHg, measured by peripheral cuff. Serum ethanol, salicylate, and acetaminophen concentrations were undetectable. An arterial blood gas drawn after intubation and sodium bicarbonate administration demonstrated pH 7.44, pCO2 47 mm Hg, pO2 244 mm Hg, HCO3 31 mEq/L. Her laboratory studies were remarkable for bicarbonate 14 mEq/L, potassium 3.7 mEq/L, Mg 2.1 mEq/L (anion gap 25 mEq/L, delta gap 1.1). Poison control recommended continued supportive care. An EKG after these interventions demonstrated a heart rate of 129 bpm, QRS duration 134 ms and QTc of 475 ms. She received an additional 100 mEq of 8.4% sodium bicarbonate and underwent gastric lavage with a 16 Fr orogastric tube and 3 L normal saline total with the removal of copious pink pill sediment. Her initial EKG ( Figure 1) demonstrated a wide complex tachycardia (QRS 150 ms, QTc 608 at 139 bpm). She underwent endotracheal intubation and received a IV bolus of 150 mEq (3 × 50 mL of 8.4% sodium bicarbonate) and was then started on an infusion of sodium bicarbonate (150 mEq sodium bicarbonate diluted in 850 mL water with 5% dextrose) at 100 mL/hr, after which her heart rate decreased to the 130 s. Her physical exam was notable for minimally reactive, dilated pupils (6–7 mm) with horizontal nystagmus, flushed dry skin, shallow respirations, and no response to painful stimuli. Her initial axillary temperature was 36.2 C, heart rate 155 beats per minute, respiratory rate 30 breaths per minutes, blood pressure 151/66 mm Hg, and fingerstick glucose 173 mg/dL. The patient arrived to the ED obtunded after less than 10 min in transit. En route she had 2 witnessed generalized seizures for which she received by IV 2 mg lorazepam, 150 mg amiodarone, and 500 mL 0.9% saline bolus.Īctions in the Emergency Department (ED). Emergency medical services (EMS) found the patient obtunded, hypotensive (no blood pressure recorded), and with a wide complex tachycardia (rate 190 beats per minute). The patient’s home medications include fluphenazine, lithium, ziprasidone, temazepam, and lansoprazole, all of which were accounted for.Īctions in the field. The estimated ingestion was 300 × 25 mg capsules (7.5 grams total, 83 mg/kg). The patient was in her usual state of health until her family found her one hour prior to arrival with generalized shaking next to a newly purchased and completely empty bottle of Benadryl™. Here, we report a case of a patient refractory to standard treatment after a massive diphenhydramine ingestion in whom ILE averted cardiovascular collapse.Ī 30-year-old 90 kg female with schizophrenia presented to our Emergency Department after an intentional ingestion of DPH. In 2011, the American College of Medical Toxicologists made no recommendation for or against the use of ILE. Systematic research on the efficacy for ILE outside local anesthetic toxicity is lacking, although there is a recent systematic review of preclinical data. However, cardiac arrest occurred within one minute after administering ILE in 2 cases of cardiogenic shock after massive diltiazem ingestion. Case reports suggest it may rescue cardiovascular collapse from other lipid-soluble or cardioactive drugs, including DPH, beta-blockers, calcium channel blockers, quetiapine and sertraline, as well as parasiticides and herbicides. Intravenous lipid emulsion (ILE) was first described as a rescue agent for cardiovascular collapse from lidocaine and bupivacaine. Large DPH ingestions are associated with wide-complex tachycardia, seizures, and death, reflecting its sodium channel blocking (type IA antidysrhythmic), antimuscarinic, and serotonergic properties. DPH is the most commonly reported antihistamine taken in overdose however, fatal ingestions are rare. It is commonly referred to as an antihistamine, a usage we follow in this report. Diphenhydramine (DPH) is a lipophilic histamine inverse agonist that readily crosses the blood-brain barrier.