Set of clinical red flags identified as checklist for possible EGPA
Checklist can be used to evaluate, diagnose patients in clinical practice: Study
Researchers have identified a set of clinical red flags that could help detect eosinophilic granulomatosis with polyangiitis (EGPA), the rarest type of ANCA-associated vasculitis (AAV).
Among the red flags are specific high-level thresholds of eosinophils, a type of immune cell, combined with other signs including asthma, nasal polyps, lung nodules, heart-related abnormalities, symptoms of nerve damage, and/or purplish-red bumps on the skin.
The findings, based on a systematic review of literature and consensus of multidisciplinary medical experts, provide “clinicians with an evidence-based checklist tool that can be integrated into their routine practice,” researchers wrote.
The study, “Red flags for clinical suspicion of eosinophilic granulomatosis with polyangiitis (EGPA),” was published in the European Journal of Internal Medicine.
High blood levels of white blood cells known as eosinophils in EGPA
EGPA is a rare form of AAV, a group of autoimmune diseases marked by small blood vessel inflammation and damage. EGPA differentiates from other AAV types by the presence of eosinophilia, or high counts of eosinophils in the blood.
“The typical presentation includes upper and lower respiratory tract involvement, [nerve damage outside the brain and spinal cord], cardiac [heart] involvement, and skin lesions,” the researchers wrote.
However, the disease “can present with a variety of clinical manifestations, frequently non-specific, that often overlap with other [conditions]” marked by blood vessel inflammation and eosinophilia, the researchers wrote, adding that this frequently leads to “a significant delay in diagnosis.”
Given that “there are no commonly agreed diagnostic criteria for EGPA,” researchers in Spain systematically reviewed EGPA-related studies published up to September 2022 to identify clinical red flags for EGPA in those older than 6 years.
A total of 86 studies were included in the analysis. A multidisciplinary team of experts then assessed whether clinical signs identified in the studies were specific enough to EGPA and if they were easy to uncover in the clinical setting.
Based on the quality of the evidence and whether there was consensus between experts about the relevance of each possible sign for EGPA, 40 red flags were categorized into four strength levels of recommendation.
Goal to develop evidence-based checklist tool for clinical practice
The goal was to develop an evidence-based checklist tool for use in clinical practice.
The experts agreed an EGPA diagnosis should be considered for patients, 6 years and older, with blood eosinophil counts higher than 1 billion cells/L, or higher than 500 million cells/L if patients were given any medication that may alter eosinophil levels.
The presence of asthma and/or nasal polyps (noncancerous growths) associated with chronic sinusitis “should reinforce a suspicion of EGPA above other eosinophilic disorders,” the researchers wrote.
Besides asthma and nasal polyps, highly relevant signs of EGPA included other respiratory conditions, heart-related signs, blood vessel and skin abnormalities, neurological damage, kidney problems, more general signs, and certain biopsy-based findings.
The additional presence of at least one other red flag should further reinforce EGPA suspicion, the experts wrote.
Highly relevant respiratory symptoms included lung nodules, the presence of eosinophils in lung structures or fluid, and lung bleeding or coughing up blood.
Also considered highly relevant were heart problems, particularly those affecting the heart muscle and the fluid-filled sac that surrounds the heart, and those caused by reduced blood supply, in patients without risk factors for cardiovascular disease.
Other red flags included painful, pale or bluish fingers; purplish-red bumps on the skin; symptoms of damage to nerves outside the brain and spinal cord such as abnormal skin sensation; and inflammation in the kidneys’ filtering units.
Certain general symptoms could also be highly relevant EGPA signs
Certain general symptoms, including fever, feeling unwell, fatigue, depression, or weight loss not attributable to any other cause, were also considered highly relevant signs of EGPA, as well as certain biopsy findings related to eosinophils and blood vessel inflammation.
The presence of ANCAs, the self-reactive antibodies that most commonly drive AAV-related damage, and particularly those targeting the myeloperoxidase enzyme that are more frequent in EGPA, was also considered highly indicative of EGPA.
Signs of medium relevance included other respiratory, cardiovascular, skin, neurological, and kidney problems, as well as certain gastrointestinal, eye, and muscle-related symptoms.
“We were able to identify a coherent set of red flags and develop a clinical checklist tool for use in clinical practice that can be used to evaluate patients, raise suspicion for EGPA, and prompt further investigation,” the researchers wrote.
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