Pulmonary eosinophilia

Pulmonary eosinophilia.

Tropical eosinophilia is a hypersensitivity response to a helminthic parasite, particularly filarial parasite (Wuchereria).

The syndrome is characterised by pulmonary manifestations and peripheral blood eosinophilia of more than 2000/mm3.

Aetiology

Tropical eosinophilia is an allergic reaction to helminthic parasites, particularly filarial worms.

Other parasites implicated are ascaris, toxocara and ankylostoma.

Clinical features

Tropical eosinophilia can present in various forms:

Asymptomatic form.

Respiratory form (commonest).

Alimentary form.

A form with constitutional disturbances.

A form with generalised lymphadenopathy and hepatosplenomegaly.

The common respiratory form may be either acute or chronic.

The acute type presents with high-grade fever, exertional breathlessness and cough with scanty expectoration.

The chronic type presents with vague ill-health, low-grade fever, exertional dyspnoea and cough with scanty expectoration.

Physical signs include bilateral rhonchi and crepitations, particularly basal.

Investigations

Total leucocyte count is raised.

Peripheral blood eosinophilia of more than 2000/mm3.

Raised serum IgE levels.

Sputum examination shows clumps of eosinophils and Charcot-Leyden crystals. Chest radiograph shows bilateral, diffuse, fine mottling in many patients.

Pulmonary function tests show restrictive and obstructive ventilatory defects.

Treatment

Diethylcarbamazine 6 mg/kg/day in divided doses for 3 weeks.

Long-standing and resistant cases are treated with prednisolone and bronchodilators.