Munchausen stridor-a strong false alarm of anaphylaxis

Beyond the appearances: exploring complexities in anaphylaxis differential diagnosis

PURPOSE OF REVIEW

Anaphylaxis is a severe, and potentially life-threatening hypersensitivity reaction whose diagnosis is based on clinical signs and symptoms and their prompt recognition. The presence of mimics and unusual presentations necessitate a careful evaluation and expertise in the field, due to potential diagnostic errors and hence a delay in the treatment.The aim of this review is to analyze and make an overview of the potential differential diagnosis of anaphylaxis, focusing on the clinical challenges of recognizing these conditions effectively among similar others.

RECENT FINDINGS

The presence of mimics and unusual presentations of anaphylaxis necessitate a careful evaluation, emphasizing the importance of a comprehensive diagnostic approach.Tryptase is well known marker of mast cells activation, and a useful tool assisting the diagnosis of anaphylaxis, helping to differentiate it from atypical mimickers.

SUMMARY

The differential diagnosis of anaphylaxis comprises a very wide setting, and a systematic approach assessing different categories of cardiovascular, skin, respiratory airway, neuropsychiatric, and hematologic systems, can facilitate recognition of the correct diagnosis of this complex and life-threatening condition.

Hymenoptera Venom Immunotherapy Meets Factitious Disorder

Factitious disorder on self is a psychiatric disorder in which individuals fabricate or induce signs or symptoms of a disease. Factitious anaphylaxis, with symptoms suggestive of a life-threatening allergic reaction, is extremely rare. Several cases of factitious disorder reactions during allergen immunotherapy for airborne allergens have been reported. We report the case of a young female patient who presented factitious anaphylaxis during venom immunotherapy to vespid venom extract. Symptoms of stridor, dyspnea, coughing and loss of consciousness were observed during the built-up phase of venom immunotherapy, mimicking allergic reactions to the venom extracts. Diagnosis of factitious disorder prompted the discontinuation of venom immunotherapy.

Approach to Idiopathic Anaphylaxis in Adolescents

Anaphylaxis is a potentially-life threatening condition. Adolescents are particularly vulnerable due to increased risk-taking behaviors, poor disease management, and minimized perception of risk. Although most anaphylaxis can be attributed to food, drug, or venom allergy via a detailed history and confirmatory studies, in nearly 1 in 5 cases, the cause may not be obvious. Clinical differentials including rare allergens, cofactors, mast-cell disorders, and mimic disorders can increase the likelihood of discovering of the cause of anaphylaxis.

Drug provocation tests in children: All that glitters is not gold

A proper allergy work-up, based on the gold standard drug provocation test (DPT), usually rules out suspected drug hypersensitivity in children. These tests are generally open, given their high efficiency compared with double-blind placebo-controlled DPTs. Although their negative predictive value is excellent, no studies have calculated their positive predictive value, highly dependent on the prevalence of the disease. Most studies have found a rate of <5%-10% of true beta-lactam hypersensitivity in children. Given this low prevalence (pre-test probability), a few false-positive results can significantly reduce the estimated positive predictive value. False positives may arise from the nocebo effect during the test, including nocebo by proxy, or from observer bias, which depends on professional expertise and organizational circumstances. Some studies have found a high rate of tolerance on a second DPT in children who failed the first, but these results may be affected by the interval between the two tests, of a year or more in most cases, reflecting a loss of hypersensitivity over time. Taking into account the low rate of positive DPTs, with commonly mild reactions, we suggest confirming nonsevere positive DPTs with a second provocation performed soon after the first, especially in the case of beta-lactam antibiotics, in order to improve the diagnostic accuracy, de-label more patients, and achieve a better estimation of true drug hypersensitivity prevalence. In case of mild immediate reactions, the potential benefits of a second DPT should be carefully weighed against the risk of anaphylaxis.

Conducting an Oral Food Challenge: An Update to the 2009 Adverse Reactions to Foods Committee Work Group Report

Oral food challenges are an integral part of an allergist's practice and are used to evaluate the presence or absence of allergic reactivity to foods. A work group within the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology was formed to update a previously published oral food challenge report. The intention of this document was to supplement the previous publication with additional focus on safety, treatment of IgE-mediated allergic reactions, guidance for challenges in infants and adults, psychosocial considerations for children and families participating in an oral food challenge, specific guidance for baked milk or baked egg challenges, masking agents and validated blinding recipes for common food allergens, and recommendations for conducting and interpreting challenges in patients with suspected food protein-induced enterocolitis syndrome. Tables and figures within the report and an extensive online appendix detail age-specific portion sizes, appropriate timing for antihistamine discontinuation, serum and skin test result interpretation, written consents, and instructional handouts that may be used in clinical practice.

Factitious Disorder Masquerading as a Life-Threatening Anaphylaxis

Factitious disorder is a psychiatric disorder in which sufferers intentionally fabricate physical or psychological symptoms in order to assume the role of the patient, without any obvious gain. We present a case of a 23-year-old female with chronic urticaria who presented with dyspnea, dysphasia, mild generalized erythema, abdominal cramps, and headache. She was tachypneic and hypotensive. This was her third admission with similar symptoms within the last 7 months. Tryptase, complement, anti-SM/RNP, Sjogren, Scl-70, C3, and C4 were negative. Computed tomography–guided bone marrow biopsy showed no mast cells. Flow cytometry did not show any immunophenotypic reaction. Other possible differentials including pregnancy, autoimmune disorders, and infections including hepatitis, thyroid disorder, and age-related malignancies were ruled out. After a thorough review, malingering disorder was ruled out, but we noticed the patient’s intent of assuming a sick role. Later, the patient was diagnosed with major depressive disorder. Factitious anaphylaxis can present with multiple presentations including a life-threatening condition that mimics true anaphylaxis. A better approach would be thorough clinical evaluation and early multidisciplinary involvement. This case highlights the importance of further evidence-based studies in factitious disorder to decrease the disease burden and reduce the health care cost.

Critical Care Management of the Patient With Anaphylaxis: A Concise Definitive Review

OBJECTIVES

Anaphylaxis is a rapidly progressive life-threatening syndrome manifesting as pruritus, urticaria, angioedema, bronchospasm and shock. The goal of this synthetic review is to provide a practical, updated approach to the evaluation and management of this disorder and associated complications.

DATA SOURCES

A MEDLINE search was conducted with the MeSH of anaphylaxis, anaphylactic reaction, anaphylactic shock, refractory anaphylaxis and subheadings of diagnosis, classification, epidemiology, complications and pharmacology. The level of evidence supporting an intervention was evaluated based on the availability of randomized studies, expert opinion, case studies, reviews, practice parameters and other databases (including Cochrane).

STUDY SELECTION

Selected publications describing anaphylaxis, clinical trials, diagnosis, mechanisms, risk factors and management were retrieved (reviews, guidelines, clinical trials, case series) and their bibliographies were also reviewed to identify relevant publications.

DATA EXTRACTION

Data from the relevant publications were reviewed, summarized and the information synthesized.

DATA SYNTHESIS

This is a synthetic review and the data obtained from a literature review was utilized to describe current trends in the diagnosis and management of the patient with anaphylaxis with a special emphasis on newer evolving concepts of anaphylaxis endotypes and phenotypes, management of refractory anaphylaxis in the ICU setting and review of therapeutic options for the elderly patient, or the complicated patient with severe cardiorespiratory complications. Most of the recommendations come from practice parameters, case studies or expert opinions, with a dearth of randomized trials to support specific interventions.

CONCLUSION

Anaphylaxis is a rapidly progressive life-threatening disorder. The critical care physician needs to be familiar with the diagnosis, differential diagnosis, evaluation, and management of anaphylaxis. Skilled intervention in ICUs may be required for the patient with complicated, severe, or refractory anaphylaxis.

Criteria positive and criteria negative anaphylaxis, with a focus on undifferentiated somatoform idiopathic anaphylaxis: A review and case series

Background: Undifferentiated somatoform (US) idiopathic anaphylaxis (IA) is considered a psychogenic disorder characterized by a lack of observable physical findings and poor response to treatment. Although failure to diagnose true anaphylaxis can have disastrous consequences, identification of US-IA is crucial to limit unnecessary expenses and use of health care resources. Objective: To better define the presentation and understand the potential relationship between US-IA and underlying psychiatric comorbidities. Methods: We retrospectively reviewed 110 visits by 107 patients to our institution for evaluation and management of anaphylaxis over a 1-year period. The patients were classified as having either criteria positive (CP) or criteria negative (CN) anaphylaxis based on whether they met Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network Symposium criteria for the clinical diagnosis of anaphylaxis. Patient characteristics, including objective and subjective signs and symptoms, and the presence of psychiatric diagnoses were collected and analyzed. Statistical significance was assessed by using the Fisher exact test. A literature review of US-IA and other psychogenic forms of anaphylaxis was performed. Results: Patients with CP anaphylaxis were more likely to present with hypotension, wheezing, urticaria, and vomiting than were patients with CN anaphylaxis. The patients with CN anaphylaxis were more likely to present with subjective symptoms of sensory throat tightness or swelling compared with patients with CP anaphylaxis. No significant difference was detected in the prevalence of psychiatric conditions between the two groups. Conclusion: Patients who met previously established diagnostic criteria for anaphylaxis were more likely to present with objective physical findings than those who did not meet criteria for true anaphylaxis. CN patients who presented for treatment of anaphylaxis were more likely to present with subjective symptoms. Formal diagnostic criteria should be used by clinicians when evaluating patients with suspected anaphylaxis.

Anaphylaxis

Anaphylaxis is a systemic, life-threatening disorder triggered by mediators released by mast cells and basophils activated via allergic (IgE-mediated) or nonallergic (non-IgE-mediated) mechanisms. It is a rapidly evolving, multisystem process involving the integumentary, pulmonary, gastrointestinal, and cardiovascular systems. Anaphylaxis and angioedema are serious disorders that can lead to fatal airway obstruction and culminate in cardiorespiratory arrest, resulting in hypoxemia and/or shock. Often, these disorders can be appropriately managed in an outpatient setting; however, these conditions can be severe enough to warrant evaluation of the patient in the ED and in some cases, hospitalization, and management in an ICU. Reports suggest that underdiagnosis and undertreatment of anaphylaxis are common. Several new syndromes have been described recently including bird-egg, pork-cat, delayed allergy to mammalian meat and a diverse group of mast cell activation disorders. Conditions such as postural orthostatic tachycardia syndrome, carcinoid syndrome, Munchausen stridor, and factitious anaphylaxis can present similarly and need to be included in the differential diagnosis. Anaphylaxis is a clinical diagnosis, but plasma tryptase and urinary histamine levels are often elevated, allowing diagnostic confirmation; however, diagnostic testing should not delay treatment as results may not be immediately available. The sine qua non of treatment is avoidance of any known triggers and epinephrine, which should never be delayed if this disorder is suspected. Secondary treatments include fluids, bronchodilators, antihistamines, and glucocorticoids. Patients with cardiopulmonary arrest or airway or vascular compromise require mechanical ventilation, vasopressors, and other advanced life support in the ICU.

Factitious disorder: a systematic review of 455 cases in the professional literature

OBJECTIVE

Patients with factitious disorder (FD) fabricate illness, injury or impairment for psychological reasons and, as a result, misapply medical resources. The demographic and clinical profile of these patients has yet to be described in a sufficiently large sample, which has prevented clinicians from adopting an evidence-based approach to FD. The present study aimed to address this issue through a systematic review of cases reported in the professional literature.

METHOD

A systematic search for case studies in the MEDLINE, Web of Science and EMBASE databases was conducted. A total of 4092 records were screened and 684 remaining papers were reviewed. A supplementary search was conducted via GoogleScholar, reference lists of eligible articles and key review papers. In total, 372 eligible studies yielded a sample of 455 cases. Information extracted included age, gender, reported occupation, comorbid psychopathology, presenting signs and symptoms, severity and factors leading to the diagnosis of FD.

RESULTS

A total of 66.2% of patients in our sample were female. Mean age at presentation was 34.2 years. A healthcare or laboratory profession was reported most frequently (N=122). A current or past diagnosis of depression was described more frequently than personality disorder in cases reporting psychiatric comorbidity (41.8% versus 16.5%) and more patients elected to self-induce illness or injury (58.7%) than simulate or falsely report it. Patients were most likely to present with endocrinological, cardiological and dermatological problems. Differences among specialties were observed on demographic factors, severity and factors leading to diagnosis of FD.

CONCLUSIONS

Based on the largest sample of patients with FD analyzed to date, our findings offer an important first step toward an evidence-based approach to the disorder. Future guidelines must be sensitive to differing methods used by specialists when diagnosing FD.

Fish-allergic patients may be able to eat fish

Reported fish allergy prevalence varies widely, with an estimated prevalence of 0.2% in the general population. Sensitization to fish can occur by ingestion, skin contact or inhalation. The manifestations can be IgE or non-IgE mediated. Several fish allergens have been identified, with parvalbumins being the major allergen in various species. Allergenicity varies among fish species and is affected by processing or preparation methods. Adverse reactions after eating fish are often claimed to be 'allergy' but could be a reaction to hidden food allergen, fish parasite, fish toxins or histamine in spoiled fish. Identifying such causes would allow free consumption of fish. Correct diagnosis of fish allergy, including the specific species, might provide the patient with safe alternatives. Patients have been generally advised for strict universal avoidance of fish. However, testing with various fish species or preparations might identify one or more forms that can be tolerated.