Tropical pulmonary eosinophilia

A rare form of eosinophilic lung disease associated with parasitic infections

Tropical pulmonary eosinophilia (TPE) is a rare and distinct form of eosinophilic lung disease that is associated with infection by certain filarial parasites, primarily Wuchereria bancrofti and Brugia malayi. It is characterized by a marked increase in eosinophils in the blood and lungs, leading to respiratory symptoms.

Pathophysiology

Tropical pulmonary eosinophilia is caused by an exaggerated immune response to the microfilariae of the filarial parasites. These parasites are transmitted to humans through the bite of infected mosquitoes. Once inside the human host, the microfilariae migrate to the lungs, where they trigger a hypersensitivity reaction. This reaction is mediated by IgE antibodies and results in the recruitment of eosinophils to the lung tissue.

Eosinophil, a type of white blood cell involved in allergic reactions and parasitic infections

The accumulation of eosinophils in the lungs leads to inflammation and damage to the lung tissue, causing the characteristic symptoms of TPE. The condition is more prevalent in tropical and subtropical regions where filarial infections are endemic.

Clinical Presentation

Patients with tropical pulmonary eosinophilia typically present with a chronic cough, wheezing, and shortness of breath. These symptoms are often mistaken for asthma or other respiratory conditions. Other symptoms may include fever, weight loss, and fatigue. The cough is usually dry and may be accompanied by nocturnal wheezing.

Diagnosis

The diagnosis of tropical pulmonary eosinophilia is based on clinical presentation, laboratory findings, and response to treatment. Key laboratory findings include:

• Elevated levels of eosinophils in the blood (eosinophilia)
• Elevated serum IgE levels
• Positive serology for filarial antigens

Chest X-rays and pulmonary function tests may show evidence of lung involvement, such as interstitial infiltrates and restrictive lung disease.

Treatment

The primary treatment for tropical pulmonary eosinophilia is the administration of diethylcarbamazine (DEC), which is effective in killing the microfilariae and alleviating symptoms. Treatment typically results in rapid improvement of respiratory symptoms and a decrease in eosinophil counts.

Prognosis

With appropriate treatment, the prognosis for patients with tropical pulmonary eosinophilia is generally good. However, if left untreated, the condition can lead to chronic lung damage and respiratory failure.

Prevention

Preventive measures include controlling the spread of filarial infections through mosquito control programs and the use of preventive medications in endemic areas.

Related pages

• Eosinophilia
• Filarial infection
• Asthma
• Diethylcarbamazine