Leffler's syndrome

Loeffler's syndrome is an allergic disease characterized by an increase in the number of eosinophils in the peripheral blood and the presence of transient eosinophilic infiltrates in one or both lungs. Or - eosinophilic volatile pulmonary infiltrate, simple pulmonary eosinophilia, simple eosinophilic pneumonia.

There are two types of Löffler syndrome.

1. Loeffler syndrome I - eosinophilic volatile infiltrate.
2. Loeffler II syndrome is a restrictive cardiomyopathy.

ICD-10 code

J82. 41,42. Eosinophilic asthma, Loeffler's pneumonia.

Eosinophilic pneumonia is widespread, more often in the tropics. It develops in men and women with equal frequency, mainly at the age of 16-40 years.

What causes Loeffler syndrome?

Löffler's syndrome was first described in 1932 by Professor Wilhelm Löffler of the University of Zurich. He proved that helminths, whose larvae migrate through the lungs, play a role in the development of eosinophilic inflammation of the lung tissue.

Currently, the syndrome is a group of inflammatory processes of various etiologies in one or both lungs.

Almost any parasite (ascarids, hookworms, trichinella, strongyloides, toxocara, pinworms, filaria, liver fluke, cat fluke, schistosomes and other flatworms) can cause Löffler's syndrome. Thus, recently, patients of this group have often been diagnosed with toxocariasis, caused by the invasion of the larvae of the nematodes Toxocara canis and Toxocara cati, intestinal parasites of cats and dogs.

Inhalation allergens may play a role in the development of the syndrome: pollen, fungal spores, some industrial substances (in particular, nickel dust), drugs (sulfonamides, penicillins, gold compounds). However, in many cases it is impossible to determine the etiology of the pulmonary infiltrate, and then we are talking about eosinophilic pneumopathy.

The mechanism of development of Leffler syndrome

The formation of Löffler syndrome I is based on an immediate-type allergic reaction, as evidenced by the “volatile” nature of the infiltrates and their complete regression without the formation of secondary pathological foci.

Elevated IgE levels were often found in the blood of patients with eosinophilic pneumonia. Hypereosinophilia and hyperimmunoglobulinemia are aimed at eliminating parasites from the body. Intensive eosinophilic infiltration of lung tissue and an increased number of eosinophils in the blood indicate the participation of the eosinophilic chemotactic factor of anaphylaxis and the formation of foci of allergic inflammation. This substance is secreted by mast cells (labrocytes) when they are activated by immune (due to IgE) and non-immune mechanisms (histamine, fragments of complement components, especially C5a).

In some cases, Löffler syndrome develops according to the Arthus phenomenon due to the formation of precipitating antibodies to antigens. Sometimes in eosinophilic

Lymphocytes are found in the infiltrates, which indicates the involvement of cell-mediated allergic reactions in the pathogenesis.

How does Loeffler syndrome manifest itself?

In most cases, patients do not complain. Less common symptoms include cough (dry or with a small amount of viscous sputum, in some cases with blood), subfebrile temperature, and often signs of bronchospasm.

Auscultation reveals dry wheezing, predominantly in the upper parts of the lungs. Leukocytosis with a large number of eosinophils (up to 50-70%) is detected in the blood; eosinophilia reaches its maximum after the appearance of pulmonary infiltrates.

The “volatile” nature of infiltrates is typical: they can disappear on their own after a few days, without leaving scarring changes in the lung tissue.

With massive hematogenous dissemination of larvae and eggs of parasites (ascarids, schistosomes, trichinella) into human tissues and organs, including the lungs, shortness of breath, cough, fever, skin rash, and wheezing in the lungs (pneumonitis) occur.

Long-term existence of infiltrates may be caused by invasion of parasites directly into lung tissue, for example, when infected with the nematode Paragonimus westermani. Adults migrate into the lung tissue through the diaphragm and intestinal wall, involving the pleura in the pathological process. As a result of inflammation, fibrous nodes are formed, which can merge to form cystic cavities.

Classification

Etiopathogenetic classification

• Loeffler syndrome caused by parasitic invasion.
• Loeffler's syndrome is caused by sensitization to aeroallergens.
• Loeffler's syndrome, which developed as a result of drug allergy.

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How to recognize Loeffler syndrome?

Syndromic diagnosis is usually straightforward. It is based on the typical combination of volatile pulmonary infiltrates with high blood eosinophilia. Difficulties often arise in establishing the etiology of Löffler syndrome.

Allergic history data are of great importance:

• seasonal exacerbations of rhinoconjunctival syndrome and asthma, a clear connection between symptoms and professional and everyday factors;
• indications of previously identified allergic diseases;
• family history;
• pharmacological anamnesis.

Laboratory research

Laboratory diagnostics are performed to confirm the data of the anamnesis and physical examination.

• In a general blood test, high eosinophilia (up to 20%) is usually recorded at the onset of the disease, but with chronicity of the process, the number of eosinophils may not exceed normal figures. High levels of IgE in the blood are often detected (up to 1000 IU/ml).
• General sputum analysis may reveal eosinophils and Charcot-Leyden crystals.
• In the analysis of feces, in some types of parasitic invasion, helminth eggs are found. In this case, the development cycle of the parasites should be taken into account. Thus, in the case of primary infection with roundworms, the larvae penetrate the lungs only after 1-2 weeks, and their eggs can be found in feces only after 2-3 months. In toxocariasis, the parasite larvae in the human body do not develop to adulthood, and therefore eggs are not found in feces.
• Skin tests are useful for etiological diagnostics with helminth allergens, pollen, and lower fungal spores. When indicated, provocative nasal and inhalation tests are prescribed.
• Serological tests include the precipitation reaction and the complement fixation reaction.
• Cellular tests - Shelley basophil degranulation reaction, mast cell degranulation reaction with corresponding allergens, as well as detection of specific IgE using radioallergosorbent test and ELISA.

Instrumental research

X-ray examination reveals single or multiple fuzzy rounded infiltrates in the lungs, localized subpleurally, most often in the upper parts of both lungs. With prolonged infiltrative inflammation, fibrous nodes may form as a result of the disease, which, merging, form cystic cavities.

To assess bronchial patency, a respiratory function test is performed, and if necessary, bronchomotor tests.

Indications for specialist consultation

• To identify allergic diseases, a consultation with an allergist is necessary.
• If allergic rhinitis is suspected, a consultation with an ENT doctor is recommended.

Example of diagnosis formulation

Main diagnosis: Loeffler syndrome I.

Etiological diagnosis: toxocariasis.

Form of the disease: visceral form.

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Treatment of Loeffler syndrome

Since spontaneous recovery is possible, drug therapy is often mg administered.

The main goal of treatment is to eliminate the etiologic factor. Deworming is prescribed, and, if possible, contact with allergens (aeroallergens, medications) is eliminated.

Antiparasitic treatment

In case of helminthic invasion, antiparasitic drugs are indicated. In recent years, the following effective and well-tolerated drugs have been widely used: albendazole (for children over 2 years old) orally 400 mg once;

• carbendacim orally 0.01 g/kg once;
• mebendazole (children over 2 years old) orally 100 mg once;
• pyrantel orally 10 mg once.

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Treatment with glucocorticoids

Early administration of glucocorticoids should be avoided, as they accelerate the resolution of infiltrates but make it difficult to establish a correct diagnosis. However, in the absence of spontaneous recovery, prednisolone is sometimes prescribed at an initial dose of 15-20 mg/day; the dose is reduced by 5 mg every other day. The daily dose is divided into three doses. The course of treatment is from 6 to 8 days.

In addition to the listed drugs, in the presence of manifestations of broncho-obstructive syndrome, beta-adrenergic agonists are prescribed for inhalation, aminophylline orally, and basic therapy for bronchial asthma is carried out.

Indications for hospitalization

• The impossibility of complete elimination of household, epidermal, pollen allergens from the environment.
• Severe parasitic infection accompanied by dehydration.

How to prevent Loeffler syndrome?

• Hygienic measures aimed at preventing helminthic invasions.
• Consultation of patients with respiratory allergies (the need to stop contact with specific aeroallergens should be explained).
• In case of professional sensitization, the professional route is studied and a change of job is recommended.
• An individual selection of pharmacological drugs is carried out to prevent drug allergies.

Forecast

Generally favorable.

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Information for the patient

Strict adherence to hygiene measures is necessary, including for patients who keep pets at home.

Patients with allergic diseases should follow the allergist's recommendations for taking medications and herbal preparations.