Polmonite eosinofilica cronica

Question 1

General findings

Answer 1

Eosinophilic pneumonia comprises a group of lung diseases in which eosinophils (a type of white blood cell) appear in increased numbers in the lungs and usually in the bloodstream.

Certain disorders, drugs, chemicals, fungi, and parasites may cause eosinophils to accumulate in the lungs. The number of eosinophils increases during many inflammatory and allergic reactions, including asthma, which frequently accompanies certain types of eosinophilic pneumonia. Eosinophilic pneumonia differs from typical pneumonias in that there is no suggestion that the tiny air sacs of the lungs (alveoli) are infected by bacteria, viruses, or fungi. However, the alveoli and often the airways do fill with eosinophils. Even the blood vessel walls may be invaded by eosinophils, and the narrowed airways may become plugged with an accumulation of secretions (mucus) if asthma develops.

Question 2

Cause

Answer 2

• Cigarette smoke
• Certain drugs (for example, penicillin, aminosalicylic acid, carbamazepine, L-tryptophan, naproxen, isoniazid, nitrofurantoin, phenytoin, chlorpropamide, and sulfonamides [such as trimethoprim/sulfamethoxazole])
• Chemical fumes (for example, cocaine or nickel inhaled as a vapor)
• Fungi (typically Aspergillus fumigatus)
• Parasites (particularly roundworms, including nematodes)
• Systemic disorders (for example, eosinophilic granulomatosis with polyangiitis)

Question 3

Manifestazioni

Answer 3

Acute eosinophilic pneumonia progresses quickly. It may cause fever, chest pain worsened by deep breathing, shortness of breath, cough, and a general feeling of illness. The level of oxygen in the blood can decrease severely, and acute eosinophilic pneumonia can progress to acute respiratory failure in a few hours or days if not treated.

Löffler syndrome may cause mild respiratory symptoms, if any. A person may cough, wheeze, and feel short of breath but usually recovers quickly.

Chronic eosinophilic pneumonia, which slowly progresses over days or weeks, is a distinct disorder that may also become severe. It tends to remit and recur on its own and may worsen over weeks or months. Life-threatening shortness of breath can develop if the condition is not treated.

Question 4

Diagnosis

Answer 4

• Chest-x-ray: bilateral peripheral or pleural-based opacities, most commonly in the middle and upper lung zones, are described as the photographic negative of pulmonary edema and are virtually pathognomonic
• Demonstrating eosinophilia in peripheral blood, bronchoalveolar lavage fluid, or lung tissue: Bronchoalveolar lavage is usually done to confirm the diagnosis. Eosinophilia > 40% in bronchoalveolar lavage fluid is highly suggestive of chronic eosinophilic pneumonia; serial bronchoalveolar lavage examinations may help document the course of disease.
• HRCT

Diagnosis is based on demonstration of opacities on chest x-ray and identification of eosinophilia (> 450/microL [0.45 × 109/L]) in peripheral blood, bronchoalveolar lavage fluid, or lung biopsy tissue. However, pulmonary eosinophilia may occur in the absence of peripheral eosinophilia. Pulmonary opacities on chest x-ray associated with blood eosinophilia are sometimes called PIE (pulmonary infiltrates with eosinophilia) syndrome.

Eosinophils are primarily tissue-dwelling and are several hundred–fold more abundant in tissues than in blood. Consequently, blood eosinophil numbers do not necessarily indicate the extent of eosinophilic involvement in affected tissues. Eosinophils are most numerous in tissues with a mucosal epithelial interface with the environment, such as the respiratory, gastrointestinal, and lower genitourinary tracts. Eosinophils are not present in the lungs of healthy people, so their presence in tissue or bronchoalveolar lavage fluid (> 5% of differential count) identifies a pathologic process.

Eosinophils are exquisitely sensitive to corticosteroids and completely disappear from the bloodstream within a few hours after administration of corticosteroids. This rapid disappearance from the blood may obscure the diagnosis in patients who receive corticosteroids before the diagnostic assessment is instituted.

Question 5

Chronic eosinophilic pneumonia

Answer 5

Chronic eosinophilic pneumonia is not truly chronic; rather it is an acute or subacute illness that recurs (thus, a better name might be recurrent eosinophilic pneumonia). The prevalence and incidence of chronic eosinophilic pneumonia are unknown. Etiology is suspected to be an allergic diathesis. Most patients are nonsmokers.

Patients with chronic eosinophilic pneumonia often present with fulminant illness characterized by cough, fever, progressive breathlessness, wheezing, and night sweats. The clinical presentation may suggest a community-acquired pneumonia. Asthma accompanies or precedes the illness in > 50% of cases. Patients with recurrent symptoms may have weight loss.

Question 6

Treatment

Answer 6

• Systemic corticosteroids

- Sometimes maintenance therapy with inhaled corticosteroids, oral corticosteroids, or both