Overview
The disease was first described by Rufio in 1932, and is therefore also known as Rufio syndrome. It is characterized by diffuse pulmonary infiltrates with elevated eosinophil counts in the peripheral blood, mild pulmonary symptoms, most of which include only a mild cough, and a self-limiting course, often resolving spontaneously within 3-4 weeks.
Etiology
The syndrome is most likely a transient alveolar hypersensitivity reaction, with common causes being parasitic infections and drug reactions. The cause is not identified in about 1/3 of patients. The disease is seasonally prevalent in some areas, so environmental antigenic factors are hypothesized to be a possible cause in some areas.
Ascaris lumbricoides infection is the most common cause of the disease, and a variety of Ascaris lumbricoides substances have strong antigenic properties. It has been experimentally demonstrated that after feeding on roundworm eggs, larvae migrating to the lungs can develop this disease. Typical pulmonary manifestations are associated with elevated eosinophils. Other parasites that cause the disease are hookworms, filarial worms, tapeworms, gingerbread worms, trichinellae, and amoeba protozoa. Drugs include para-aminosalicylic acid, aspirin, penicillin, nitrofurantoin, prednisone, chlorosulfopropylurea, hydralazine, meglumine, sulfasalazine, and methotrexate. Inhalation of pollen and fungal spores has also been reported.
Symptoms
Simple pulmonary eosinophilic infiltrate is characterized by mild fever, fatigue, and a slight dry cough. In severe cases, acute symptoms such as high fever, paroxysmal cough, and asthma may occur, and occasionally respiratory failure may occur. There are wet or dry rales in the chest and sometimes turbid sounds on percussion. The spleen may be slightly enlarged. Eosinophils are increased, sometimes up to 60% to 70%, larger than normal eosinophils, and contain large granules. Severe children with systemic vasculitis may have multisystem damage.
Clinically, there are two common pulmonary infiltrates with eosinophilia syndrome, i.e., simple pulmonary eosinophilia and tropical pulmonary eosinophilia, related to the migration of parasitic larvae, but also related to drugs or chemicals, symptoms are mild, asthma may or may not be present, the X-ray manifestations are characterized by pulmonary infiltrative lesions in a transient and travelling, serum IgE is normal, and the duration of the disease is relatively short, mostly for a few weeks or so. Tropical eosinophilia is mainly associated with filarial, canine and feline roundworm and hookworm infections, cough with asthma, increased serum IgE, and variable duration of illness, sometimes up to several weeks, and the chronic type can be more than 1 year.
Examination
X-ray manifestation is often a light density, unclear boundary flaky shadow, distributed in unilateral or bilateral lungs, transient wandering, mostly disappeared in 1 to 2 weeks, and can appear in other parts of the body, most of the time not more than 1 month.
Peripheral blood leukocytes may be normal or slightly elevated, and eosinophils are obviously elevated. More eosinophils can also be seen in the sputum.
Diagnosis
The diagnosis of the disease is based on the presence of elevated eosinophils in the peripheral blood with foci of wandering pulmonary infiltrates and mild clinical symptoms that resolve spontaneously. If Ascaris lumbricoides infection is suspected, a fecal egg collection test can be performed 2 months after the onset of symptoms, i.e., after the caecilians have developed into worms in the body.
Differential diagnosis
It should be differentiated from asthmatic pulmonary eosinophilic infiltrate, tropical pulmonary eosinophilic infiltrate, delayed pulmonary eosinophilic infiltrate, and infiltrative tuberculosis.
Treatment
Generally no treatment is needed. Drugs should be stopped immediately if they are suspected to be drug-induced. Those caused by parasites can be treated with deworming. Adrenocorticotropic hormone may be used if symptoms are significant or recurrent.
Prevention
Pay attention to dietary hygiene to prevent infection of roundworm, hookworm, filariasis, tapeworm, gingerbread worm, trichinella and amoeba, etc.; be careful with p-aminosalicylic acid, aspirin, penicillin, nitrofurantoin, pau-tazone, chlorosulfonylurea, hydrazine phenylprazine, meglumine, sulfonamides, and methotrexate.