A case of chronic eosinophilic pneumonia

Clinical History

A 54-year-old female patient presented to the outpatients asthma clinic with a few months history of cough, fatigue, shortness of breath on minimal exertion and wheezing. Blood investigations included an elevated erythrocyte sedimentation rate and eosinophilia at 2.0 X10⁹ / L. No fever was documented.

Imaging Findings

The initial chest radiograph at presentation was normal. After a few weeks of worsening symptoms, the repeat chest radiograph showed patchy areas of airspace shadowing mostly worse on the left. No pleural effusions were present. The patient was admitted for further investigations. Bronchoalveolar lavage studies revealed a 55% differential eosinophilic count. Subsequent radiograph showed an increase in airspace shadowing with a peripheral distribution. A chest CT was organised. This confirmed the patchy airspace shadowing with a characteristic "photographic negative of pulmonary oedema". In addition there were areas of ground glass shadowing but no mediastinal lymphadenopathy. The patient was treated with high dose steroids after which a remarkable clinical improvement was observed after few days. Follow-up HRCT 1 month post treatment were completely normal. As the dose of steroids was being tapered down, the patient relapsed a few months later.

Discussion

Pulmonary eosinophilic diseases are a group of disorders characterised by lung opacities and tissue or peripheral eosinophilia. The diagnosis is confirmed with the presence of pulmonary opacities associated with peripheral eosinophila, parenchymal eosinophilia confirmed by open lung biopsy or transbronchial biopsy, or a high eosinophil differential on brochoalveolar lavage studies [1].
Chronic eosinophilic pneumonia is commoner in women. Nonspecific symptoms of malaise, fever, weight loss and night sweats are amongst the clinical manifestations. Chest symptoms include cough and dyspnoea, which are always present, while wheezing occurs in around 50% of patients. Dyspnoea severe enough to require ventilation is rarely present except in the presence of idiopathic acute eosinophilic pneumonia. Asthma is also a common occurrence in these patients. Extra thoracic manifestations are never present [2, 3].
Laboratory findings invariably demonstrate a high erythrocyte sedimentation rate and eosinophilia usually in excess of 1000/mm³. Bronchoalveolar lavage findings reveal high eosinophil levels in the region of 12 - 95% of the total cell count. This is an important differential finding in comparison to cryptogenic organising pneumonia, which shares many clinical and radiological characteristics. In the latter, lymphocyte counts are higher than eosinophils. Pulmonary function tests are an unreliable diagnostic factor. They are normal in a third of patients while both restrictive and obstructive patterns have been documented [3].
Typical findings on chest X-ray include non-segmental patchy areas of airspace shadowing involving the lung periphery and mostly the upper lobes. This pattern may however be seen in less than 50% of cases. CT demonstrates similar features. Less common findings are the presence of ground glass change, nodules and reticulation. CT performed after more than 2 months from beginning of symptoms will show linear opacities parallel to the pleural surface. Only 9% of cases have a pleural effusion [1].
The basis of treatment of chronic eosinophilic pneumonia is oral steroids. A dramatic response in blood results is noted within hours while radiographs return to normal within a few days. There is no consensus on the dose and duration of treatment. Initial prednisone doses of 0.5 and 1 mg/kg/day tapering down the dose for a total of 6 - 12 months. Relapse is observed in 50% of patients. The response to higher doses of steroids is similar to that of the first episode [3].

Differential Diagnosis List

Final Diagnosis

Chronic eosinophilic pneumonia

URL:	https://eurorad.org/case/10037
DOI:	10.1594/EURORAD/CASE.10037
ISSN:	1563-4086