Hypereosinophilic lung diseases - Chronic idiopathic eosinophilic pneumonia
Dr Ian Glaspole MBBS PhD FRACP Respiratory Physician. Alfred Hospital, Prahran 3181
Description: Chronic eosinophilic pneumonia is a non cancerous disease that causes eosinophils - a type of white blood cell - to gather within the lung’s alveoli, the tiny air sacs of the lung responsible for oxygen and carbon dioxide exchange with the blood. It is a condition that occurs in the absence of any recognizable cause.
Epidemiology and diagnosis: The condition is characterised by a variety of symptoms which include generalised symptoms such as fever, weight loss and night sweats, along with symptoms referable to the lung such as cough, breathlessness and wheezing. Approximately half of all patients with the condition have asthma, but the majority of patients do not have a history of other allergic diseases. The disease may occur at any age, but has a peak incidence in the fifth decade. Symptom onset is usually insidious and generalised symptoms predominate. As such patients are frequently diagnosed only after several months of having become unwell. Respiratory failure or involvement of other organs apart from the lungs are not typical features and suggest that a different diagnosis should be looked for.
Blood tests usually demonstrate marked elevation of the eosinophil count, in association with a raised ESR and neutrophilia. The IgE level is usually not elevated or is only marginally increased. Chest x-rays demonstrate pneumonia, often occurring at the edges of the lung, and coming and going at involved sites. CT scans usually confirms the peripheral location of the disease and the absence of features of other causes for lung eosinophilia. Bronchoscopy, a procedure whereby under sedation a narrow fibre-optic endoscope is inserted into the airway via the nose or mouth, may show elevation of the eosinophil count within samples taken from affected areas of the lung. Sometimes a lung biopsy is performed, and this will also generally demonstrate accumulation of eosinophils within the alveolar walls and airspaces.Management: In the great majority of cases, treatment is required for the condition to resolve. Usually, treatment is begun with a steroid containing medication, such as prednisolone. Typical starting doses range between 25 mg and 50 mg daily. Treatment is usually tapered, with a typical course of treatment lasting between three and nine months. Frequently, the disease will relapse after cessation of therapy or with tapering of the steroid dose. As such, many patients need to use prednisolone into the long term. Often, long-term control can be achieved with daily low-dose prednisolone.
http://www.arnold.org.au