Anaphylaxis presenting as cardiac ischemia

​EMS is called to a single family residence for a 84 year old female who was reportedly experiencing difficulty breathing.

On EMS arrival the patient is found sitting in a chair. She appears acutely ill and lethargic. Skin is pale and very diaphoretic. There is no sign of respiratory distress. Breath sounds are clear bilaterally.

The daughter states that she complained of nausea after eating dinner. She went to the bathroom to throw up and returned in this condition.

She states that the patient has a history of heart disease including stents “many years ago.” She further states that the patient recently had a stress test and the cardiologist said that the stents were “getting old.”

The patient starts dry heaving.

Vital signs are assessed.

  • HR: 110
  • RR: 18
  • NIBP: 142/120
  • Temp: 97.2 F
  • SpO2: 88% on RA

Oxygen is given via NRB mask at 15 LPM. The SpO2 increases to 93%.

The patient denies chest pain. However, she is noted to be rubbing her epigastric area. When questioned about it she states “it feels like something is there.”

The cardiac monitor is attached.

subendocardial ischemia 01 wm

A 12-lead ECG is obtained (with some difficulty due to the patient’s diaphoresis and dry heaving).

subendocardial ischemia 02 wm

It is noted to show ST-segment elevation in lead aVR with widespread ST-segment depression consistent with subendocardial ischemia.

(Update: Based on comments on various Facebook pages where this case is posted some folks are not familiar with the ECG signs of subendocardial ischemia. See Five Primary Patterns of Ischemic ST-Depression Without ST-Elevation. Some Are STEMI Equivalents at Dr. Smith’s ECG Blog.)

Based on this paramedics give 324 mg aspirin and 0.4 mg nitroglycerin.

The patient is placed on a stair chair and removed from the residence. In the back of the ambulance vital signs are re-assessed. The blood pressure is manually auscultated as the initial reading was believed to be potentially inaccurate.

  • HR: 108
  • RR: 18
  • BP: 130/90
  • SpO2: 93% with oxygen

An 18 G IV is started in the left antecubital space. A second dose of 0.4 mg nitroglycerin is given.

After the second nitroglycerin the NIBP reads 123/84.

Online Medical Control is contacted via cell phone and a report is given.

On arrival the patient really looks bad. She is placed in a hospital bed and vital signs are assessed. The patients blood pressure is now 63/30. The staff is concerned that paramedics gave the patient nitroglycerin since “she doesn’t have any chest pain.”

The paramedics are worried about the low blood pressure, too, and start to second guess the appropriateness of their interventions. The firefighter who auscultated the blood pressure (an EMT who just finished paramedic school) is adamant that he heard Korotkoff sounds.

The attending physician comes in and assesses the patient. During the physical exam he notes angioedema and a swollen tongue. He orders 0.3 mg epinephrine SQ, 50 mg diphenhydramine IV, methylprednisolone, and famotidine.

The patient is also given a fluid bolus. The pressure comes back and eventually the following 12-lead ECG is recorded.

anaphylaxis after treatment wm

The ST-segment depression is almost entirely resolved.

The patient receives rapid sequence induction and is intubated due to concerns about the swollen tongue.

The attending physician, perhaps sensing that the paramedics were feeling badly about the case, assures them that it was one of the more challenging cases he’s seen in his career and that nothing about the patient’s presentation was straight forward.

When you hear hoofbeats, you should think of horses, not zebras. But every once in a while it turns out to be a zebra. Medicine is a humbling profession!


About author

Tom Bouthillet
Tom Bouthillet - 25 posts

Tom Bouthillet (@tbouthillet) is Editor-in-Chief of (@ECGTraining) and Fire Captain/Paramedic in South Carolina where he is the Emergency Cardiac Care Program Manager and the STEMI and CARES Site Coordinator of his fire department.

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