Eosinophils matter:

Inspired by yesterday’s @CPSolvers case + last week’s NEJM case, reprising this thread with 5 more real case examples of this take-home point:

In acute presentations, eosinophilia is often a pivot point: it dramatically shifts/narrows the ddx.

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Background: Glucocorticoids kill eosinophils. In acutely ill/stressed patients, the high endogenous cortisol should melt away your normal eos.

If you're acutely ill and have eosinophilia, the eos are probably related to why you're sick.

https://twitter.com/sargsyanz/status/1113043222283120641?s=20

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Background: it's absolute counts that matter. Eosinophilia is defined as AEC > 450.

Total WBC 2K with 15% eos? AEC is 300 (normal)
Total WBC 20K with 3% eos? AEC is 600 (elevated)

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Main eosinophilia causes: NAACP+1

Neoplasm: heme > solid
Allergy: drugs or atopy
Adrenal insuff: (loss of tonic suppression of eos)
Collagen-vascular dz: vasculitis, lupus
Parasites (helminths) & some fungi (cocci, aspergillus)

+ primary hypereo syndromes (eosin. X-itis)

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All this summarized in excellent @CPSolvers schema.

Now on to brief summaries of 5 recent cases where eosinophilia changed everything.

5/ https://clinicalproblemsolving.com/dx-schema-eosinophilia/

Case A: a middle-aged woman with new heart failure.. pulmonary edema, runs of VT, borderline pressures.

Would have pursued only usual considerations and workup... but 700 eos in the blood.

Dx: eosinophilic myocarditis (needs steroids!)

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Case B: Young man with severe pneumococcal pneumonia/empyema, initially in ICU, now improving on floor. Develops renal failure, fevers. No diff checked in a few days. 2200 blood eos.

Dx: drug hypersensitivity

Pearl: NEW onset eos while in hospital? Probably drugs

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Case C: Man sees PCP for dyspnea, diagnosed with COPD, given steroids.

Breathing initially better, but admitted to hospital with severe sepsis, blood growing GNRs. 500 eos.

Dx. disseminated strongyloidiasis

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Case D: Older guy admitted for rectal pain seemingly from bad hemorroids, and "lumbar strain, needing pain control/PT." He wasn't that sick, but 900 unexplained eos still expanded the differential and led to more aggressive eval.

Dx: rectal cancer with mets to spine

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Case E: Older Honduran woman with fevers, night sweats, and faint pulmonary opacities on CT. Infections were most highly considered, but blood 1100 eos..

Dx: eosinophilic granulomatosis with polyangiitis

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Conclusion: Sometimes eosinophilia will be from a known, trivial, or unrelated cause like atopic disease.

But especially in acutely ill patients, it's often the key. Consider its differential, and how it may fit with the patient's presentation.

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