Ossifying pulmonary granulomatosis

The migration of larvae of Ascaris lumbricoides from the intestine through the lungs and bronchial tree into the oesophagus and back into the intestine is a well-known feature of the life cycle of this nematode. The passage through the lungs remains often symptomless, but, in an investigation on experimental infection in man, Takata (1951) found cough in 71-4% of those infected with human ascaris and in 68-4% of those infected with pig ascaris. If eggs are fed to a rat or guinea-pig with a little water, the animal shows, after a few days, sneezing and laboured respiration. In many cases of Loeffler's syndrome, the transient benign eosinophilic infiltration of the lungs, and also in tropical eosinophilia (Beaver and Danaraj, 1958) ascaris was found to be the causative organism. Keller, Hillstrom, and Gass (1932) state that the changes seen on radiological examination, which have been attributed to the migration of ascaris larvae, are similar to those seen in the childhood type of hilar tuberculosis and may also resemble the changes which occur following repeated non-specific infections of the lungs. Practically nothing is known of the pathological basis of pulmonary symptoms in ascaris infestation. Beaver and Danaraj found in their case thickening of the alveolar walls and infiltration with various types of leucocytes and partial organization of exudate with fibroblasts in the alveoli. In experimental animals, haemorrhage into the alveoli and respiratory bronchioli, inflammation of bronchial and peribronchial tissues, and heavy muco-purulent exudation into the bronchioles were found. 'The symptoms resulting from such infections are transient, however, because A. lumbricoides larvae that fail to make the migration from lungs or other tissues die within a few weeks and are destroyed, at least in experimental animals' (Beaver and Danaraj, 1958).