Beta blocker overdose
Patient presentation:
An 82 year old male patient presents to the ER via EMS with generalized weakness and fatigue. Pt denies chest pain, fevers, cough, frequent urination, or flu/cold like symptoms in the past week. Abdomen is soft and non-tender, pupils equal and reactive to light bilaterally, and pulses are weak but present. Patient is oriented but slightly lethargic, hands and feet cool to touch but circulation is intact, and lung sounds are clear bilaterally. Vitals are as follows: blood pressure 85/50, pulse 50, respirations 14, pulse oxygen 98% on 4 Liters via nasal cannula, and temperature 97.6 degrees Fahrenheit. The patient has a history of hypertension and hyperlipidemia for which he takes labetalol 200mg in the evening and Lipitor® 40mg in the morning. The patient states he was not feeling well since yesterday and took his evening dose of labetalol early, at noon, to see if it made him feel better. The patient had 2 large bore IVs started and normal saline bolus of two liter given wide open. Patient was placed on the monitor, and oxygen was given via nasal cannula. Labs were drawn and sent to the lab.
Possible diagnosis:
sepsis, hypoglycemia, beta blocker overdose, hypovolemia
Tests:
ECG shows sinus bradycardia with widening of QRS complex
Chest X-ray shows no acute changes, no lung infiltrates
CBC and CMP were within normal limits
Lactate was 2.5mmol/L (slightly elevated) and Bicarb was 17mmol/L (slightly decreased)
Cardiac enzymes were within normal limits
Blood glucose was 87
Treatment:
The patient was placed on pacer pads on standby in case he loses consciousness. The patient received two liter normal saline and blood pressure remained at 88/56. The patient received glucagon 10mg IV bolus. His blood pressure rose to 98/65 and pulse to 70. Pt states that he feels slightly better. While awaiting admission to the floor, the patient’s blood pressure starts to go down again to 79/54 despite extra IV fluid. The patient received another glucagon bolus and placed on a glucagon drip of 2mg/min. The patient is then transferred to a cardiac telemetry floor for further monitoring.
Diagnosis:
Since the patient reacted well to the glucagon, it was assumed that he had overdosed on his beta blocker. The plasma half-life of labetalol is 6 - 8 hours; the pt was maintained on a glucagon drip until the effects of labetalol dissipated.
Case created by Zina Potorac, 2010.