Case Study
The bedside nurse initiated a rapid response event after the patient was found to be in acute respiratory distress. Upon the arrival of the rapid response team, the patient was found to be a 34-year-old male with a history of alcohol abuse admitted a few hours ago for suspicion of aspiration pneumonia. He was receiving his first dose of ampicillin-sulbactam when he developed dyspnea and significant facial swelling.
Vital Signs
Temperature: 97.6 °F, axillary
Blood Pressure: 90/60 mmHg
Heart Rate: 110 beats per min (bpm)
Respiratory Rate: 32 breaths per min
Oxygen Saturation: 80% on room air, 96% on 15 L/min non-rebreather mask.
Focused Physical Examination
The patient was a young male in severe respiratory distress, tachypneic using accessory muscles of respiration. Appropriate personal protective equipment was established, and the patient was examined. Visible pitting edema was noticed around the eyelids, lips, and throat. There was minimal air entry in bilateral lung fields with inspiratory and expiratory wheezing. The remaining examination was unremarkable.
Interventions
A cardiac monitor and defibrillator pads were attached to the patient. He was emergently given epinephrine 0.5 mg intramuscular with methylprednisolone 125 mg IV on suspicion of allergic angioedema and possible anaphylaxis. The patient was emergently intubated via the nasotracheal route and transferred to the intensive care unit (ICU) for further management.
Final Diagnosis
Allergic angioedema with anaphylaxis.
Angioedema
Definition and Diagnosis
Angioedema is an abrupt onset, transient, localized swelling of deep skin layers or mucous membranes that commonly affects the face, periorbital areas, lips, larynx, and gastrointestinal (GI) tract. Angioedema can have two different underlying mechanisms ( Table 33.1 ). Identification of the predominant mechanism is essential as the treatment of these two entities differs significantly. However, this identification can be challenging given the lack of specific diagnostic tests and overlap of symptoms.
| Features | Mast cell-mediated/Histaminergic angioedema (Allergic) | Bradykinin-mediated angioedema (Non-allergic) |
|---|---|---|
| Trigger | Allergic triggers such as medication, food, insects, environmental allergens | Hereditary or acquired; medication induced is a common subtype of acquired such as Angiotensin-converting enzyme inhibitors associated with angioedema |
| Onset | Fast – may evolve over minutes | Slower – evolves gradually over 24 to 36 h |
| Systemic involvement | Involves other organ systems in the setting of anaphylaxis – hypotension, wheezing, nausea/vomiting, and diarrhea | Usually does not involve other organ systems; sometimes can involve the gastrointestinal tract causing pain, diarrhea, and nausea/vomiting |
| Treatment | Responds to antihistamines and steroids; 90%-100% will improve | Unresponsive to antihistamines/steroids; 2%-10% may seem to improve |
The two main mechanisms of developing angioedema are mast cell mediated and bradykinin mediated. The complete detail of these mechanisms is not in the scope of this text, but a quick schematic is presented in Figs. 33.1 and 33.2 , and the main differences between these two are listed in Table 33.1 .
