Epidemiology of pulmonary eosinophilia in rural south India--a prospective study, 1981-86

Tropical pulmonary eosinophilia masquerading as asthma in a 5-year-old girl

Tropical pulmonary eosinophilia (TPE) is an exaggerated immunological response to filarial antigens mainly seen in adults in endemic areas and is uncommonly reported in children. The diagnosis is frequently delayed as it mimics asthma clinically, while the chest radiograph might show miliary mottling which is often confused with that in pulmonary tuberculosis. A 5-year-old girl presented with episodes of nocturnal cough, wheeze, low grade fever and breathlessness for the previous 4 months and was being treated for asthma. The absolute eosinophil count was markedly raised (53 × 10⁹/L) with prominent bilateral infiltrates on the chest radiograph. Serology for microfilaria and a test for microfilaria antigens were positive and the patient showed a dramatic response to diethylcarbamazine, which confirmed the diagnosis of TPE. TPE is an important differential diagnosis of asthma especially in endemic areas.

Tropical pulmonary eosinophilia--a review

Tropical pulmonary eosinophilia (TPE) is a syndrome of wheezing, fever and eosiniphilia seen predominantly in the Indian subcontinent and other tropical areas. Its etiological link with Wuchereria bancrofti and Brugia malayi has been well established. The pathogenesis is due to an exaggerated immune response to the filarial antigens which includes type I, type III and type IV reactions with eosinophils playing a pivotal role. Peripheral blood eosinophilia is usually striking with levels over 3000/μl being common. High serum levels of IgE and filarial-specific IgE and IgG are also found. The pathology may vary from an acute eosinophilic alveolitis to histiocytic infiltration depending on the stage of the disease. While earlier studies had suggested that the disease runs a benign course, more recent work has shown that untreated TPE could result in a fair degree of respiratory morbidity. Pulmonary function tests may show a mixed restrictive and obstructive abnormality with a reduction in diffusion capacity. The bronchoalveolar lavage (BAL) eosinophil count has a negative correlation with the diffusion capacity. Treatment consists of diethylcarbamazine (DEC) for at least three weeks. Despite treatment with DEC, about 20 per cent of patients may relapse. Steroids have shown to have a beneficial effect but the exact dose and duration is yet to be confirmed by randomized controlled trials. A specific and easily available marker is required for TPE in order to distinguish it from other parasitic and non-parasitic causes of pulmonary eosinophilia.

Respiratory morbidity due to ammonia exposure among the employees of a urea manufacturing industry located in western part of India

Ammonia is produced in the fertilizer industry. The amount of ammonia inhaled by employees of a urea manufacturing industry is very high. It would be interesting to study whether such an amount has any impact on the employees working there for many years. This study explores the magnitude of respiratory morbidity among employees of a urea manufacturing industry and to establish its association with exposure to ammonia. Data was collected related to significant respiratory illnesses of all the employees over a period of 10 years using computer-based medical record system of the industry′s hospital. The results obtained from the data analysis showed that there is no cause and effect relationship between exposure to ammonia and respiratory morbidity. Thus it was advised to the medical authority at industry to go for mass treatment with anthelmintics and that all the employees should be screened for specific allergens and this information should be used while managing respiratory morbidity.

Tropical pulmonary eosinophilia: pathogenesis, diagnosis and management

PURPOSE OF REVIEW

Tropical pulmonary eosinophilia is predominantly seen in the tropical and subtropical regions of the world. It is being increasingly reported from other parts of world, however, due to increases in global travel and migration. This review focuses attention on recent developments.

RECENT FINDINGS

Tropical pulmonary eosinophilia is an occult form of human filariasis. The gamma-glutaryl transpeptidase found in the infective L3 stage larvae of Brugia malayi has been found to have similarities with the gamma-glutaryl transpeptidase present on the surface of human pulmonary epithelium. It has, therefore, been proposed that filarial gamma-glutaryl transpeptidase may play an important role in the pathogenesis of tropical eosinophilia. Airway hyperresponsiveness, manifesting as asthma-like syndrome, has been reported in tropical pulmonary eosinophilia and it has been suggested that interleukin-4 induces and interferon-gamma suppresses filarial-induced airway hyperresponsiveness. The intense eosinophilic alveolitis seen in acute tropical pulmonary eosinophilia is suppressed by 3 weeks of treatment with diethylcarbamazine citrate. A mild eosinophilic alveolitis along with radiological, physiological and hematological abnormalities, though with reduced intensity, persists in some patients however.

SUMMARY

A chronic mild interstitial lung disease has been found to persist in tropical pulmonary eosinophilia despite treatment.

Chronic pulmonary disorders, including tropical pulmonary eosinophilia, in villages with endemic lymphatic filariasis in Tanga region and in Tanga town, Tanzania

To investigate the occurrence of tropical pulmonary eosinophilia (TPE), studies were undertaken in 3 villages with endemic lymphatic filariasis in the coastal area of Tanga Region, Tanzania, and in the outpatient clinic of Bombo Regional Hospital in Tanga town; 73 persons from the villages and 104 from the outpatient clinic with a history of lung disease suggestive of TPE were included in the study. Following clinical examination, lung function tests and chest X-rays were performed. Total leucocyte and eosinophil counts were recorded. Parasitological examinations included blood for microfilariae and stools and urine for eggs of intestinal helminths and Schistosoma haematobium respectively. Total immunoglobulin (Ig) E and specific antifilarial IgE and IgG4 were measured. Suspected TPE cases were treated with diethylcarbamazine, 6 mg/kg for 12 d, and were followed up 14, 90 and 360 d after treatment. Three persons fulfilled the criteria for TPE. Their response to treatment was marked, with clinical improvement, reduction in eosinophil count and reduced titres of specific antifilarial IgE and IgG4. Although TPE is present in Wuchereria bancrofti endemic areas of East Africa, it appears to be rare, as in other endemic areas.