Today in our Jacobs afternoon conference, Dr. Tiffany Tanaka gave a very practical, case-based talk on how to read peripheral blood smears as well as common findings for platelets and leukocytes. She gave a primer on hematopoietic lineages and differentiation, how to read a peripheral smear systematically, and some common, high-yield findings that are often tested on boards. Special thanks to her for helping to teach not one, but two conferences today!!
Today our fantastic hematologic malignancy expert, Dr. Asimakopoulos, walked us through an interesting case of amyloidosis! We discussed the fine details of what exactly SPEP, UPEP, and Immunofixation are, and how they are useful in the workup of patients with infiltrative protein disease. We also reviewed the most common types of amyloidosis: AL (light chain), AA (chronic inflammatory), and how to distinguish these patients both clinically and with laboratory data. Thank you Dr. Asimakopoulos!
This afternoon, Sophie Cannon presented an interesting case of a female in her 30s with a history of chronic urticaria who presented in respiratory distress, tachycardia and throat swelling following the ingestion of a meal prepared at a restaurant. A similar event had happened previously, months ago though the symptoms were not as severe, and self resolved. This prompted the discussion of upfront recognition and treatment of patients whose presentations are concerning for anaphylaxis, the diagnosis of which is purely clinical, and can be made in the following scenarios:
We also reviewed the pathophysiology of the various mechanisms by which anaphylaxis occurs. Most are likely familiar with the canonical IGE mediated pathways, Which upon re-exposure, allergen-specific IgE antibodies bind to allergens and form allergen-specific IgE immune complexes, which then activate mast cells and basophils, causing degranulation and release of preformed histamine, leukotriene, prostaglandins, and platelet activating factor. There are several additional pathways worth mentioning, including the non-IgE pathways involving IgG, cytokine release response pathways involving IL-6, IL-1B, and TNFa, mixed CRR/IgE pathways, as well as the direct complement C5a activating pathways.
The patient was ultimately treated with IM Epinephrine, which prompted resolution of the patient’s respiratory symptoms, glucocorticoids to help prevent biphasic anaphylaxis, as well as antihistamines to treat the patient’s pruritis and skin manifestations. Thank you to Sophie and Dr. Broide for a great case, and fantastic teaching!
Take Home Points:
- Anaphylaxis is a clinical diagnosis; early recognition and empiric treatment can prevent respiratory and cardiovascular collapse and death
- Multiple mechanisms lead to “anaphylaxis,” including those that are mediated by T-cells and macrophages, which may present with a sepsis-like presentation, due to release of pro-inflammatory cytokines IL-6, IL-1B, and TNF-a
- IM Epinephrine is the gold standard therapy upfront and is the only measure that has been shown to effectively treat respiratory compromise associated with anaphylaxis. Glucocorticoids, antihistamines, and leukotriene modulators are all adjunct strategies and should not be used in place of epinephrine. Caution should be used when considering IV Bolus epinephrine, as outcomes have not been demonstrated to be superior, but have instead been linked to cardiovascular complications such as MI/Stroke.
Figures were adapted from Wilfox et al, Journal of Asthma and Allergy, 2018
For our PM report at JMC this Wed, R2 Lizzy Hastie led us through an interactive worksheet, a review of the literature on the pros and cons of the LRINEC score for identifying Necrotizing Fasciitis, AND a photo quiz of soft tissue infections. Take home point, as with any tool, clinical judgment is paramount! Trust your instincts and involve surgery early if nec fasc is on your differential. Early in the course, the labs may not yield a high LRINEC score.