Parasitic lung infections: nematodes

Published on July 11, 2013   16 min

A selection of talks on Clinical Practice

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This is the second lecture on parasitic lung infections. I am Dr. V. K. Vijayan, advisor at Bhopal Memorial Hospital and Research Centre Bhopal, India, and was the former Director of Vallabhbhai Patel Chest Institute, University of Delhi. The second lecture is on parasitic lung infections caused by nematode parasites.
Lung infections caused by nematode parasites are as follows: Ascaris lumbricoides causes pulmonary ascariasis, Ancylostoma duodenale and Necator americanus cause pulmonary strongyloidiasis. Strongyloides stercoralis causes pulmonary strongyloidiasis, Wuchereria bancrofti, and Brugia malayi cause tropical pulmonary eosinophilia.
Dirofilaria immitis and D. repens cause pulmonary dirofilariasis. Toxocara canis and T. cati cause visceral larva migrans. Trichinella spiralis causes pulmonary trichinellosis.
Pulmonary ascariasis is caused by Ascaris lumbricoides through soil contamination of hands or food with eggs. The eggs hatch into larvae in the small intestine. The larvae then penetrate the wall of the intestine and travel via capillaries and the lymphatic system to the reach the pulmonary circulation, then travel through the right side of the heart to reach the lungs. The respiratory symptoms include: chest pain, cough, hemoptysis, shortness of breath, and wheezing.
The important hematological finding in pulmonary ascariasis is leukocytosis with eosinophilia. Chest radiographs show unilateral or bilateral, transient, migratory, nonsegmental opacities. Stool examination may show ascaris eggs two to three months after respiratory symptoms. Pulmonary disease is a self-limiting disease.