Eosinophilia

Churg-Strauss Syndrome

Necrotizing granulomatous inflammation with eosinophils involving multiple organs, especially lungs and heart usually in px with hx of asthma, airway hypersensitivity

nervous manifestions of eosinophilia

cerebellar dysfunction / ataxia seizures, stroke meningitis, encephalopathy mononeuritis multiplex paraparesis all mediated by neurotoxin

What causes hypereosinophilia? (3)

eosinophilic leukemia idiopathic HES (hypereosinophilic syndrome) Loeffler syndrome

pulmonary manifestions of eosinophilia

infiltrates, fibrosis, effusion, nodule

4 M/C solid tumors associated with eosinophilia?

lung, cervical, GI, carcinomatosis

Worldwide, M/C cause of eosinophilia is

parasitic infection

Mechanisms (2) by which eosinophils kill?

phagocytosis degranulation onto surface of large organisms

tx of eosinophilia?

prednisone hydroxyurea if prednisone cannot be titrated down

FIP1L1-PDGFRa fusion gene

recurrent molecular abnormality in patients with eosinophilia-associated myeloproliferative neoplasms aka CHIC2 deletion

eye manifestions of eosinophilia

retinal vasculitis, microthrombi

hypereosinophilia most affects what organ?

the heart

heart with eosinophilia often appears

thick with densely fibrotic ventricles

Eosinophil cationic protein

toxic to parasites, neurotoxin

high tryptase suggests

very active mast cells

What is in eosinophil granules?

- Major basic protein - cationic proteins - peroxidases - lipid mediators (PAF, Leukotriene C4) - neurotoxin - cytokines

common parasites leading to eosinophilia

- Strongyloides - Protozoa - Metazoa (nematodes, cestodes, trematodes, scabies)

cardiac manifestions of eosinophilia

- constrictive pericarditis - myocarditis - valve regurg (MR, TR)

Absolute eosinophil count should be less than

0.5 x 10^9

DRESS syndrome

Drugs, Rash, Eosinophilia, Swelling, Serum ALT

Which cytokines stimulate eosinophils?

IL-5 most specific IL-1, IL-3, GM-CSF

tx of eosinophilia with FIP1L1-PDGFRa fusion gene

Imatinib steroids

What do eosinophils use to kill parasites?

Major Basic Protein

Loeffler syndrome

A restrictive cardiomyopathy caused by an endomyocardial fibrosis with an eosinophilic infiltrate and eosinophilia

main role of IL-4 in allergic response is

driving IgE production

GI manifestions of eosinophilia

ascites, diarrhea, gastritis, colitis, pancreatitis, hepatitis, hepatic nodules

M/C cause of eosinophilia in industrialized countries?

atopy

Normal eosinophil count

0.5-4%

widespread organ dysfunction is seen in hypereosinophilia when eosinophil count is >

20k-100k / uL

clinically significant eosinophilia is defined as

> 1000-1500 / uL and sustained

eosinophilic esophagitis is defined by

> 20 eosinophils per HPF

hypereosinophilia is defined as

> 2000-5000 / uL this is usually associated with tissue damage d/t MBP release

skin manifestions of eosinophilia

angioedema, urticaria, paulonodular lesions, mucosal ulcerations

Eosinophilia mnemonic

PACCC MAN P - parasites A - asthma C - Churg Strauss C - chronic adrenal insufficiency C - collagen vascular disease M - myeloproliferative disorders A - allergies N - neoplasia (HL, other lymphomas) + dermatitis, drug reactions

Major basic protein (MBP)

Protein that is toxic to helminths - protein secreted by eosinophils.

Main cell that activates eosinophils?

Th2 (via IL-5) minor contribution from mast cells, basophils (in allergies)

After IDing FIP1L1-PDGFRa fusion gene, the next step is

bone marrow biopsy

AML with eosinophilia

broad and bright eosinophils in bone marrow inversion 16

primary function of eosinophils

destruction of parasitic infection

MSK manifestions of eosinophilia

destructive arthritis, effusions, arthralgias, myalgias