Eosinophilic pneumonias

Eosinophilic pneumonias

OVERVIEW:

Eosinophilic pneumonias are characterized by eosinophilic lung infiltrates with or without peripheral blood eosinophilia. They are classified as acute or chronic and can be either idiopathic or secondary to other causes.
• Included are:
• Loffler's syndrome (simple pulmonary eosinophilia)
• Allergic bronchopulmonary aspergillosis (ABPA)
• Drug-induced pulmonary eosinophilia
• Tropical pulmonary eosinophilia
• Chronic or prolonged pulmonary eosinophilia
• The hypereosinophilic syndrome
• Churg-Strauss syndrome (polyarteritis nodosa) or allergic angiitis

System(s) affected: Pulmonary
Genetics: No known genetic pattern
Incidence/Prevalence in USA: Rare
Predominant age: Any age
Predominant sex: Male = Female (male in 4th decade; female in 6th decade)

SIGNS AND SYMPTOMS:

• Low grade fever
• Symptoms may be mild or life-threatening
• Cough
• Chills
• Hypoxia
• Hepatomegaly
• Dyspnea
• Wheezing
• Anorexia
• Decreased localized breath sounds
• Mucoid sputum
• Tachycardia
• Malaise

CAUSES:

• Idiopathic (though hypersensitivity suspected) in one third of cases
• Drugs/toxins (penicillin, nitrofurantoin, isoniazid, chlorpropamide, sulfonamides, antituberculous therapy (PAS), gold, aspirin, hydralazine)
• Tropical
• Parasites
• Toxocara larvae
• Filariae
• Nematodes (Strongyloides, Ascaris, Ancylostoma
• Aspergillus fumigatus (asthmatic pulmonary eosinophilia)
• Systemic vasculitis

RISK FACTORS:

• Patients with chronic disorders, e.g., asthma, cystic fibrosis
• Living or traveling in certain geographical areas, e.g., India, Ceylon, Burma, Malaysia, Indonesia, tropical Africa, South America, South Pacific
• Cigarette smoking has recently been suggested

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS:

• Tuberculosis
• Sarcoidosis
• Hodgkin's disease
• Other lymphoproliferative disorders
• Eosinophilic granuloma of the lung
• Desquamative interstitial pneumonitis
• Hypereosinophilic syndrome
• Wegener's granulomatosis

LABORATORY:

• Findings determined by etiology
• Leukocytosis
• Eosinophilia in peripheral blood
• A. fumigatus found in sputum
• Positive filarial complement fixation
• Elevated IgE levels
• Increased WBC
• Elevated ESR
• Stool examination for parasites

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS:

• Lung
• Alveolar eosinophilic filling
• Septal eosinophilic infiltration
• Septal plasma cell infiltration

SPECIAL TESTS:

• Bronchoscopy with broncho alveolar lavage
• Lung biopsy when diagnosis uncertain or clinical course is severe (rare)
• Pulmonary function studies

IMAGING:

High resolution chest CT, chest x-ray - migratory infiltrates, small pleural effusion; transient infiltrates; interstitial opacities

DIAGNOSTIC PROCEDURES:

History and physical exam with particular emphasis on drug intake, recent travel to tropical areas, and systemic symptoms

TREATMENT

APPROPRIATE HEALTH CARE:

Outpatient for milder cases. More severe cases may require inpatient care.

GENERAL MEASURES:

• Evaluate for secondary causes
• Mild cases may require no specific therapy
• Coughing and deep breathing exercises to clear secretions
• Discontinuing offending drug
• Treatment of underlying parasite infestation

SURGICAL MEASURES:

N/A

ACTIVITY:

As tolerated.

DIET:

High calorie, high protein, soft diet

PATIENT EDUCATION:

Information about activity, diet, symptoms of recurrence

MEDICATIONS

DRUG(S) OF CHOICE:

• Corticosteroid therapy. In chronic pulmonary eosinophilia, 20-40 mg prednisone daily. In Churg-Strauss syndrome may require large doses e.g., 40-60 mg of prednisone daily. Withdrawal should be possible after recovery. In chronic conditions, treatment should continue for 6-12 months.
• Treat asthma, if present
• Piperazine for Ascaris infestation
• Diethylcarbamazine [available only from the manufacturer] 6-8 mg/kg orally in 3 divided doses a day for 10-14 days for tropical pulmonary eosinophilia
• Appropriate vermifuges for helminthic infections

Contraindications: Refer to manufacturer's literature
Precautions: Refer to manufacturer's literature
Significant possible interactions: Refer to manufacturer's literature

ALTERNATIVE DRUGS:

In Churg-Strauss syndrome, cases resistant to corticosteroid therapy, adding azathioprine or cyclophosphamide may be helpful

FOLLOW UP

PATIENT MONITORING:

Physical examinations and chest x-rays until resolved

PREVENTION/AVOIDANCE:

None

POSSIBLE COMPLICATIONS:

• Some patients may show evidence of small airways dysfunction
• Delay in treatment of tropical pulmonary eosinophilia may result in irreversible pulmonary fibrosis

EXPECTED COURSE AND PROGNOSIS:

• Excellent in the milder forms
• Corticosteroid therapy is dramatically effective in more severe cases
• Relapse is rare

MISCELLANEOUS

ASSOCIATED CONDITIONS:

• Asthma
• Hypersensitivity pneumonitis
• Wegener's granulomatosis

AGE-RELATED FACTORS:

Pediatric: N/A
Geriatric: More morbidity, probably due to decreased lung capacity and likelihood of concomitant diseases
Others: N/A

PREGNANCY:

N/A

SYNONYMS:

• Loffler's syndrome
• Pulmonary infiltrates with eosinophilia syndrome (PIE)

ICD-9-CM:

518.3 eosinophilic pneumonia

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Medical Diagnosis » E » Eosinophilic pneumonias