Scoring system can help emergency doctors diagnose HAE: Study
Symptoms, family history, treatment response ranked
A new scoring system may help emergency physicians diagnose hereditary angioedema (HAE), potentially allowing patients to receive treatment faster, a study found.
Nine HAE experts worked together to design the system, which assigns patients numerical scores based on their symptoms, family history, and responsiveness to certain treatments.
“This tool can help physicians predict HAE in undiagnosed patients, enabling prompt treatment, reducing hospitalizations, healthcare costs, and improving patients’ quality of life,” the researchers wrote.
The study, “Prediction of hereditary angioedema during attacks in patients with recurrent angioedema: Awareness at a glance with the hereditary angioedema prediction score,” was published in Clinical and Translational Allergy.
HAE is a genetic form of angioedema, a set of disorders characterized by swelling attacks. In HAE, swelling is driven by the buildup of bradykinin, a signaling molecule that causes blood vessels to become more permeable, allowing fluids to leak into nearby tissues. For this reason, HAE medications often aim to reduce bradykinin levels.
Different forms, different treatments
Different forms of angioedema have different underlying causes and are typically treated in other ways. Mast cell-mediated angioedema (MMAE) involves mast cells, immune cells that release inflammatory signaling molecules, including histamine, during an allergic reaction. Medications that target mast cells, block histamine effects, or reduce inflammation — such as antihistamines, corticosteroids, and epinephrine — are commonly used to ease MMAE symptoms.
Diagnosing angioedema in the correct form is important for physicians to choose the most appropriate treatment. Specialists are likely best positioned to make these diagnoses, particularly for HAE, which is rare.
However, the severe nature of swelling attacks means many HAE patients end up in emergency departments, which are less well equipped to differentiate among the different types of angioedema, according to the researchers. They said they developed the scoring system for HAE “to assist clinicians who are unfamiliar with angioedema in predicting HAE during acute attacks.”
Nine HAE experts from four medical institutions in Turkey generated a list of clinical features that they look for when making a diagnosis. They agreed on five factors that, if present, were most useful in identifying HAE. These included the absence of hives and the presence of abdominal pain. Swelling attacks in MMAE are often accompanied by hives and other allergic symptoms. HAE, on the other hand, may cause abdominal pain, but does not typically cause hives.
Attacks beginning before age 18, a family history of HAE, and a lack of response to medications targeting mast cells were the other three factors associated with HAE.
Researchers then interviewed 155 people with MMAE and 106 people with HAE to determine if the five criteria applied. All participants had confirmed diagnoses and similar demographics, although those with HAE were significantly younger than those with MMAE (median age 35 vs. 43).
For each of the five criteria, a significantly larger proportion of patients in the HAE group fit the description. With this information, the team ran statistical analyses to determine the relative importance of each factor in predicting the type of angioedema participants had.
Based on this analysis, they excluded young age at the time of symptom onset from the final version of the system and gave a numerical score to each of the other factors. Not responding to mast cell-targeting medications was the most important variable; if a participant had experienced this, the person was assigned 53 points. Not having hives warranted an additional 23 points, having experienced episodes of abdominal pain netted 11 points, and having a family history of HAE netted 9 points.
By comparing the scores of patients with HAE and MMAE based on this scale, the researchers determined that if a patient had a score of 38 points or more, their clinicians should consider the possibility of HAE. With this cutoff value, the scoring system correctly identified 96.4% of people with HAE and 96.1% of people with MMAE.
More testing is needed to assess how well the system works on other groups of patients, according to the researchers. They said they are interested to see if it can identify people with acquired angioedema, which has some similar characteristics to HAE.
The team also hopes to further simplify the system so that emergency physicians won’t need to rely on mental calculations.
“We believe that this scoring method could be effectively adapted into an artificial intelligence application or a web-based calculator for easier use,” the researchers wrote.
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