Eosinophilia in the Tropics

Eosinophilia in the Tropics

• Eosinophilia is characterized by an elevated number of eosinophils, a type of white blood cell.
• Eosinophils are granulocytic leukocytes, similar to neutrophils in their life cycle, morphology, enzymes, metabolism, and phagocytosis.
• Acute inflammation stimulates neutrophil production and inhibits eosinophils, resulting in eosinopenia.
• Repeated or prolonged exposure to antigens, particularly those deposited in tissues, triggers eosinophilic stimulation.
• T-lymphocytes are involved in the response; they release proteins which stimulate bone marrow precursor cells to create more eosinophils.

ILO's Recommendations for Eosinophilia Diagnosis

• Understand eosinophilia terminology.
• Recognize common causes, understanding that they aren't always infectious.
• Develop a diagnostic approach to assess and accurately diagnose eosinophilia.

Eosinophilia Characteristics

• Often temporary and not harmful.
• Marked prolonged eosinophilia (without a clear cause) can result in eosinophilic syndromes, impacting organ systems.
• Examples of these include eosinophilic leukemia, Loeffler's endomyocardial disease, and prolonged pulmonary eosinophilia.
• Eosinophilia is a common haematological finding in tropical regions. It's seen in people with anemia, and travelers or immigrants arriving from developing countries.

Causes of Eosinophilia (Common and Occasional)

• Common:*

• Allergies (e.g., hay fever, urticaria, asthma)

• Parasite infections

• Medications (e.g., iodides, erythromycin, sulfonamides)

• Collagen vascular diseases (e.g., allergic angiitis, fasciitis, polyarteritis nodosa)

• Gastrointestinal issues (eosinophilic gastroenteritis)

• Eosinophilic syndromes

• Occasional:*

• Fungal infections (e.g., aspergillosis, coccidioidomycosis)

• Tuberculosis (TB)

• Cancers (e.g., lymphoma, lung/stomach tumors)

• Post-radiation therapy

• Miscellaneous disorders (e.g., chronic peritoneal dialysis, chronic active hepatitis, acute pancreatitis, insect bites, eosinophilic meningitis)

Worm Infections Associated with Eosinophilia

• Tissue Nematodes: Located in blood/lymphatics, skin/tissues, or gut; examples include Wuchereria Bancrofti, Brugia Malayi, and Strongyloides Stercoralis.
• Migrating Larvae: Ascaris Lumbricoides, Necator Americanus, and Ancylostoma Duodenale.
• Tissue Trematodes: Located in liver, lung, or urinary tract; examples include Schistosoma Mansoni, Schistosoma Japonicum, Fasciola hepatica, and Paragonimus Westermani.
• Tissue Cestodes: Located in liver, lung, and brain. An example of a parasitic species is Echinococcus Granulosus.

Diagnostic Approach

• Assess severity of eosinophilia (low, moderate, high).
• Determine if eosinophilia is related to presenting symptoms (e.g., in travelers).
• Consider if parasite infections are a possible cause.
• Evaluate potential causes like allergies, drugs, genetics, or exposure to infections.
• Consider blood tests, stool analysis, serology tests, skin biopsies, and radiological imaging to aid in diagnosis.

This quiz explores eosinophilia, focusing on its characteristics, causes, and diagnostic recommendations. Understand the role of eosinophils and T-lymphocytes in the response to prolonged antigen exposure. Enhance your knowledge about this condition, particularly in tropical regions.