Haematology in Systemic Disease Quiz

See Anaemia of Chronic Disease. Option E is correct. Eosinophils are white cells with orange-staining granules, and their main job is defence against large parasites such as helminths (parasitic worms), which are too big to engulf. They coat the parasite and release toxic granule contents onto it, helped by antibodies, which is why the marrow makes more of them during these infections. The rise is greatest when the worm invades tissues, for example by larvae passing through the lungs, gut wall or muscle. A patient may be quite well, and some infections cause a chronic, symptom-free state with eosinophilia as the main clue. So a raised eosinophil count in a patient with a travel history or exposure to soil or untreated water should prompt a search for parasites. The other white cell patterns help you not to confuse it: neutrophilia points to bacteria, lymphocytosis to viruses, and thrombocytopenia to severe sepsis. Eosinophilia also occurs in allergy and drug reactions, so the history decides.

• Eosinophils: white cells that defend against large parasites such as helminths.
• Trigger: the rise is greatest when the worm invades tissues.
• Clue: eosinophilia with travel, soil or untreated water exposure should prompt a search for parasites.