Difficult to treat bronchial asthma with radiological opacities

A 53-year-old man, resident of Mumbai, occasional smoker, was symptomatic since 15 years with episodic cough and paroxysmal dyspnoea associated with wheeze. His symptoms had worsened in last 4 months despite being treated with inhaled corticosteroids and bronchodilators. Physical examination revealedthe presence of bilateral rhonchi andcrepitations. Chest radiograph [Figure 1] showed bilateral reticulonodular opacities and high-resolution computed tomography (HRCT) thorax [Figure 2] showed widespreadth centrilobular nodules. Complete blood count showed a total eosinophil count of 15114/mm³, total serum immunoglobulin (Ig) E was elevated (9423 IU/ml), peripheral smear for microfilaria was negative while filarial antibody (IgG) was positive. Spirometry showed forced vital capacity (FVC) of 2.17 L (61% of predicted), forced expiratory volume in 1 second (FEV₁) of 1.66 L (57% of predicted), and FEV₁/FVC of 77. He was given diethylcarbamazine 6 mg/kg for 21 days. He responded in the form of improvement in symptoms, near complete resolution of X-ray opacities and regression of centrilobular nodules on HRCT thorax. Absolute eosinophil count decreased to 810/mm³ and total IgE to 6211/mm³. Post-therapy spirometry showed improvement in FEV₁ and FVC by 570 ml and 770 ml, respectively.

Figure 1.

Chest X-ray showing reticulo-nodular opacities

Figure 2.

High resolution computed tomography (HRCT) thorax showing widespread centrilobular nodules

QUESTION

Q1: What is likely diagnosis?

ANSWER

Tropical pulmonary eosinophilia (TPE) in a case of Bronchial Asthma.

The presence of pulmonary infiltrates and peripheral eosinophilia is called the PIE syndrome. PIE syndromes occur as simple pulmonary eosinophilia, chronic pulmonary eosinophilia, tropical pulmonary eosinophilia (TPE), asthmatic bronchopulmonary aspergillosis (ABPA), Churg Strauss syndrome, and idiopathic hypereosinophilic syndrome (HES). In a known asthmatic PIE syndrome is likely to be due to ABPA or Churg Strauss syndrome. However, TPE is a common condition in the tropics and may occur in an asthmatic. Diagnosis of TPE in our case was made as patient fulfilled diagnostic criteria[1] in the form of resident of tropics, worsening of asthma symptoms, peripheral eosinophilia (>3000/mm³), elevated serum IgE (>1000 IU/ml), absence of microfilaria on peripheral smear, presence of anti-filarial antibody, and good response to diethylcarbamazine.