Perflutren lipid microspheres for echocardiogram contrast: a clinical case of anaphylaxis not caused by PEG
Bibliographic record
Abstract
BACKGROUND: ) gas encapsulated by an outer lipid shell of phospholipids and a polyethylene glycol (PEG)ylated phospholipid. Anaphylaxis to perflutren lipid microsphere is very rare, with only one case report clearly attributing the reaction to the PEG excipient. We report a novel case of anaphylaxis likely caused by a non-PEGylated component of Definity®. CASE PRESENTATION: Our patient is a healthy 54-year-old female, who underwent an exercise stress transthoracic echocardiogram using Definity® as an enhancing agent. She experienced anaphylaxis within 15 min of injection. Symptoms resolved after she was treated with diphenhydramine and epinephrine, followed by a systemic corticosteroid and ondansetron in the Emergency Department. The patient underwent allergy testing at our clinic for Definity® and various PEG-containing substances. While all PEG products tested negative, she had positive intradermal tests to Definity®. She also had negative skin prick testing to PEG 8000 and passed an oral challenge to PEG 3350, thus ruling out PEG as the causative agent of anaphylaxis. CONCLUSIONS: Our case report highlights a previously undocumented instance of anaphylaxis to Definity® not caused by PEG. We suspect the reaction to be an IgE-mediated response to a non-PEGylated component of Definity®. An alternative explanation for the reaction could be a complement activation-related pseudoallergy. This report provides critical information to physicians on the potential risks of using Definity® and contributes to growing research surrounding the profile of Definity®.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.005 | 0.003 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".