Tropical Pulmonary Eosinophilia

What is Tropical Pulmonary Eosinophilia?

Tropical pulmonary eosinophilia is a syndrome that sometimes develops when infected with Wuchereria bancrofti, Brugia malayi, etc. Brugia spp.

Most cases occur in India, Pakistan, Sri Lanka, Brazil, and Southeast Asia, South Asia, Africa, and South America. Men get sick four times more often, the peak of the incidence is 20-30 years. The cause of pulmonary eosinophilia can be other worms: roundworm, hookworm, toxocars and intestinal acne.

Pathogenesis during Tropical Pulmonary Eosinophilia

In tropical pulmonary eosinophilia, microfilariae are very quickly removed from the blood by the lungs, and the clinical manifestations are due to an inflammatory and allergic reaction to parasites deposited in the lungs. In some cases, microfilariae are retained in the organs of the reticuloendothelial system, which leads to hepatomegaly, splenomegaly, and an increase in lymph nodes. Often there is an accumulation of eosinophils in the lumen of the alveoli. In the absence of treatment, pneumosclerosis develops, leading to respiratory failure.

Symptoms of Tropical Pulmonary Eosinophilia

The main symptoms of the syndrome are coughing and choking, usually at night (possibly due to the release of microfilariae in the blood), dry cough, shortness of breath and wheezing, especially pronounced at night, as well as malaise, loss of appetite and weight loss. People usually get sick at the age of 20-40 years, men get sick 4 times more often than women. During an exacerbation in the lungs dry and wet rales are heard. In children, unlike adults, lymph nodes and liver often increase. Low-grade fever, swollen lymph nodes and marked eosinophilia (over 3000 µl). History has information about visiting the endemic focus.

Diagnosis of Tropical Pulmonary Eosinophilia

The X-ray picture may be normal, but in most cases there is an increase in bronchial and pulmonary patterns, and in the middle and lower third of the lung fields, multiple tiny or small focal shadows are sometimes seen.

Laboratory and instrumental studies. Within a few weeks, pronounced eosinophilia persists – the absolute number of eosinophils is more than 3000 μl in the temperature of minus 1, relative – more than 20-50%. The serum IgE level exceeds 1000 IU / ml. In serum and fluids obtained from bronchoalveolar lavage, antibodies to filarias are detected. Microfilariae are found in the lung tissue, they are absent in the blood. On radiographs of the chest visible enhancement of the pulmonary pattern and multiple focal shadows 1-3 mm in diameter. In the study of respiratory function, restrictive disorders and a decrease in the diffusion capacity of the lungs are detected, and in 25–30% of patients – and obstructive respiratory disorders. A lung biopsy reveals a picture of bronchopneumonia with eosinophilic infiltrates, granules with necrosis in the center are found in the interstitial tissue, and some of them have dead microfilaria. Characterized by an increase in the level of IgE in serum to 10,000-100,000 ng / ml and a high titer of antibodies to filarias.

The diagnosis in patients who have been in areas with a wide spread of filarial infections for a long time is made on the basis of the clinical picture. An important role in the diagnosis of the disease is played by characteristic radiographic changes, marked eosinophilia, and an increase in serum IgE levels. Rapid improvement in antihelminthic treatment confirms the diagnosis of tropical pulmonary eosinophilia. High titer of antibodies to filaments is a characteristic, but not pathognomonic, sign of this disease. Tropical pulmonary eosinophilia should be distinguished from bronchial asthma, Leffler syndrome, allergic bronchopulmonary aspergillosis, Churg-Strauss syndrome, systemic vasculitis (primarily Wegener’s nodosa and Wegener’s granulomatosis), chronic eosinophilic pneumonia, and hypereosinophilic syndrome Along with information about staying in an endemic focus, important symptoms of tropical pulmonary eosinophilia are the nighttime nature of asthma attacks, a very high titer of antibodies to filarial diseases, and the rapid effect of diethylcarbamazine.

Treatment of Tropical Pulmonary Eosinophilia

Tropical pulmonary eosinophilia is well treated with diethylcarbamazine. Assign diethylcarbamazine (4-6 mg / kg / day inside for 14 days). Symptoms usually subside 3–7 days after the start of treatment. With relapses that develop in 12-25% of cases (sometimes years later), a second course of treatment is required.