Week 1: Discussion RESPONSEs

UO

Uchenna Osuji

May 28 10:57pm

| Last reply May 29 3:23pm

Reply from Uchenna Osuji

Discussion Post #1: Anaphylaxis and Angioedema in a Patient with Asthma

BC is a 38-year-old man with a history of asthma. These are his vitals: 100/62, HR 126, O2 90%, RR 28, and he presents with angioedema, hives, wheezing, and tachycardia. He denies any new food or environmental exposures but had a similar episode in the past with no known cause. His current condition is consistent with idiopathic anaphylaxis, a severe allergic reaction without an identified trigger (Golden et al., 2023).

Pathophysiology

Anaphylaxis is a fast and serious allergic reaction triggered by the immune system, specifically classified as a type I hypersensitivity reaction. This process typically involves an immunoglobulin E (IgE)-mediated response in which IgE antibodies bind to allergens and activate mast cells and basophils, leading to the release of inflammatory mediators. When the body overreacts to a perceived threat, immune cells called mast cells and basophils release histamine along with other chemical mediators, such as leukotrienes, prostaglandins, and various cytokines. These substances work together to produce widespread effects: blood vessels widen (causing hypotension), become leaky (leading to angioedema and hives), and the smooth muscles in the airways contract (causing wheezing and shortness of breath from airway narrowing, or bronchospasm) (Justiz-Vaillant & Zito, 2019; Golden et al., 2023). These chemical signals also stimulate nerve endings, contributing to itching and discomfort. The drop in blood pressure causes the heart to beat faster, resulting in tachycardia. In individuals with asthma, the already sensitive airways amplify the respiratory effects of anaphylaxis (AAAAI, 2020).

Genetic and Risk Factors

Asthma and other allergic conditions often run in families. Genes that control IgE and other immune signals may increase sensitivity to allergens. Asthma also increases the risk of severe or even fatal anaphylaxis due to the already narrowed and inflamed airways (Golden et al., 2023).

Diagnostic Tests

To assess and manage this condition, appropriate diagnostic tools include:

Serum tryptase: Confirms mast cell activation (Golden et al., 2023).

Pulmonary function tests or peak expiratory flow rate: Measure airway narrowing (bronchospasm) (Peters et al., 2006).

Chest X-ray: Rules out pneumonia, pneumothorax, or other lung issues.

Allergy testing: Helps find possible triggers once the patient is stable (Justiz-Vaillant & Zito, 2019).

CBC with eosinophil count: Detects signs of allergic inflammation.

Treatment Plan

The American Academy of Allergy, Asthma & Immunology (2020) recommends intramuscular epinephrine administered into the mid-anterolateral thigh as the first and most important treatment for anaphylaxis. This reverses airway constriction, boosts blood pressure, and reduces swelling. Additional treatments include:

Oxygen therapy to treat hypoxia and support breathing.

IV fluids to improve blood pressure and treat hypotension.

H1 and H2 antihistamines, such as diphenhydramine and famotidine, to reduce swelling, itching, and hives.

Corticosteroids to prevent a delayed or second wave of symptoms.

Albuterol nebulizer to open up the airways and relieve bronchospasm.

Patients should be observed for at least 4–6 hours due to the risk of biphasic reactions. Upon discharge, the patient should be prescribed an epinephrine auto-injector, educated on avoiding triggers, and referred to an allergist for follow-up.

References

American Academy of Allergy, Asthma & Immunology (AAAAI). (2020). Anaphylaxis emergency action plan and treatment guidelines. https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/anaphylaxisLinks to an external site.

Golden, D. B. K., Wang, J., Waserman, S., et al. (2023). Anaphylaxis: A 2023 practice parameter update. Annals of Allergy, Asthma & Immunology, 132(2), 124–176. https://doi.org/10.1016/j.anai.2023.09.015Links to an external site.

Justiz-Vaillant, A. A., & Zito, P. M. (2019). Immediate hypersensitivity reactions. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK513315/Links to an external site.

Peters, S. P., Ferguson, G., Deniz, Y., & Reisner, C. (2006). Uncontrolled asthma: A review of the prevalence, disease burden and options for treatment. Respiratory Medicine, 100(7), 1139–1151. https://doi.org/10.1016/j.rmed.2006.01.006Links to an external site.

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Rebecca Bryan

May 27 11:06pm

| Last reply May 28 9:10am

Reply from Rebecca Bryan

Pathophysiological Mechanisms of Action

In the case study about the 16-year-old girl identified as “MJ” the presenting symptoms of urticaria (hives), wheezing, voice changes, and one episode of vomiting shortly after eating a shrimp burrito would indicate a Type 1 hypersensitivity reaction called systemic anaphylaxis. This reaction led to symptoms of hypotension, gastrointestinal issues, and tachycardia. MJ’s immune system, having already been sensitized from prior exposure to the allergen, reacts aggressively to the introduced substance. A common allergen, shellfish-in, in this case shrimp, is likely the catalyst for this reaction. The shrimp proteins trigger the production of Immunoglobulin E (IgE) antibodies on mast cells and basophils, which bind to the allergen. This triggers degranulation and the release of histamine, prostaglandin, and leukotrienes (Justiz-Vaillant, 2019). This reaction causes increased vascular permeability, vasodilation, bronchoconstriction, and smooth muscle contraction, which lead to symptoms such as hypotension, tachycardia, gastrointestinal issues, urticaria (hives), and airway edema.

Risk Factors and Genetic Mutations

Specific genetic mutations directly linked to the cause of anaphylactic reactions have yet to be identified. However, there is a well-documented hereditary component to the genetic tendency to develop allergic disease known as atopy. According to the National Human Genome Research Institute, these predisposed individuals often have a familial history of conditions like asthma, eczema, and allergic rhinitis, and often have elevated levels of IgE, making them more prone to hypersensitivity reactions than their counterparts.

Presentation of Symptoms

Our subject, MJ, presented with the following symptoms: hypotension, tachycardia, urticaria (hives), vomiting, wheezes, and alterations in her voice. These symptoms are congruent with the systemic effects of massive histamine and cytokine release. Her airway symptoms are in direct correlation to contractions of her smooth muscles and mucosal inflammation. Her low blood pressure is due to the increase of vascular permeability. While the Gastrointestinal distress is consistent with mast cell degranulation in the lining of her gut (Justiz-Valiant, 2019).

Blood Work and Diagnostic Criteria

While the case study supplied did not list any specific labs for MJ’s case, there are standards for suspected anaphylaxis. These diagnostic tests include serum tryptase levels collected within 1-3 hours of the onset of symptoms. Elevated levels will support the diagnosis of an anaphylaxis reaction by confirming the mast cell activation. Long-term diagnostics strategies will include outpatient referral to an allergist for the dreaded skin prick tests or Rast testing which tests for specific IgE antibodies directed at the specific antigen. While unlikely to pursue genetic testing, it is important that patients have an awareness of family history and allergies (National Human Genome Research Institute).

Treatment and Follow Up

Acute management for MJ should include epinephrine administered intramuscularly to counteract the vasodilation and bronchoconstriction. Antihistamines and corticosteroids should be provided to help relieve immediate symptoms and reduce the risk of a secondary reaction known as a biphasic reaction. Bronchodilators such as albuterol are administered to assist with any wheezing. If symptoms persist or become more severe, epinephrine drip and airway support may be indicated. Post initial treatment, MJ should be monitored for several hours to assess for the potential of any biphasic reaction (or a delayed recurrence of the reaction). At discharge, the patient should be prescribed an epinephrine auto-injector, commonly called an Epi-Pen. The patient, the patient’s family, and friends will need education on proper use of the Epi-Pen before discharge and the importance of seeking medical attention after its use. MJ and her family will also require education regarding allergen avoidance, outpatient follow-up at an allergist’s office, the importance of symptom recognition, and protocols for any future emergency responses.

References

Justiz-Vaillant, A. A., & Zito, P. M. (2019). Immediate hypersensitivity reactions. In StatPearls. Treasure Island, FL: StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK513315/

National Human Genome Research Institute. (n.d.). Genomics FAQ for advanced-practice nurses: Nurse practitioners. NIH. https://www.genome.gov/For-Health-Professionals/Provider-Genomics-Education-Resources/np-genomics-faq#npfaq1