|
Bronchiolitis obliterans & organizing pneumonia
OVERVIEW: This is a specific reaction of lung tissue to a variety of injuries. The lungs show a pattern of multiple patchy pneumonia. These are seen on chest x-ray as patchy alveolar or ground glass opacifications with or without interstitial infiltrates and may have air bronchograms as well.
System(s) affected: Pulmonary
Genetics: N/A
Incidence/Prevalence in USA: Uncommon
Predominant age: Reported cases range age 0-70, mean age 50's
Predominant sex: N/A
SIGNS AND SYMPTOMS: • Most cases present with a flu-like illness that lasts 4-10 weeks or longer. Most have been treated with antibiotics without success.
• Fever
• Dry cough
• Weight loss
• Dyspnea may be severe
• Crackles and perhaps squeaks over involved area
• Fatigue
CAUSES: Idiopathic. A complex response to a variety of injuries, such as toxic inhalation; post mycoplasma, viral and bacterial infection; aspiration; immunologic factors.
RISK FACTORS: • AIDS
• Immunocompromised patients, including transplant patients
DIAGNOSIS DIFFERENTIAL DIAGNOSIS: • Usual interstitial pneumonitis (UIP)
• Noninfectious diseases
• Tuberculosis
• Sarcoidosis
• Histoplasmosis
• Berylliosis
• Goodpasture's syndrome
• Neoplasm
• Polyarteritis nodosa
• Systemic lupus erythematosus
• Wegener's granulomatosis
• Sjogren's syndrome
• Chronic eosinophilic pneumonia
• Cryptogenic bronchiolitis
LABORATORY: • Leukocytosis with a normal differential
• Elevated ESR, usually quite elevated
• Negative cultures
• Negative serology for mycoplasma, Coxiella, Legionella, psittacosis, and fungus
• Negative viral studies
Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A
PATHOLOGICAL FINDINGS: • Intraluminal fibrosis of distal airspaces is the major pathologic feature
• Fibroblasts and plugs of inflammatory cells and loose connective tissue fill these distal airways
• The inflammatory cells are mainly lymphocytes and plasma cells
• Interstitial fibrosis is present
• The plugs of edematous granulation tissue in the terminal and respiratory bronchioles and alveolar ducts do not cause permanent damage
SPECIAL TESTS: • Pulmonary function shows a restrictive/obstructive pattern
• Flow-volume loop shows terminal airway obstruction
• Chest x-ray may show patchy alveolar opacities often in the mid or upper lung area. A ground glass pattern that may have air bronchograms.
• V/Q scan: matched patchy defects
IMAGING: • Chest x-ray - often appears more normal than the physical examination
• CT scans more accurately define the distribution and extent of the patchy alveolar opacities with areas of hyperlucency
DIAGNOSTIC PROCEDURES: • Open lung biopsy
• Transbronchial biopsy
• It may be well to use a trial of steroids as a diagnostic trial, though not all would agree
• If a diagnostic trial is successful, be prepared to treat the patient for at least a year
TREATMENT APPROPRIATE HEALTH CARE: Inpatient
GENERAL MEASURES: • Monitor blood gases or pulse oximetry
• Oxygen as necessary
SURGICAL MEASURES: N/A
ACTIVITY: As tolerated
DIET: No special diet
PATIENT EDUCATION: Followup is especially important. Relapse is common. Treatment is prolonged. If medication tapered too rapidly, relapse may well occur.
MEDICATIONS DRUG(S) OF CHOICE: • Prednisone
• 60 mg daily for 1-3 months
• Then tapered over a few weeks to 20 mg (this dose may later be given as alternate day therapy). Increase length of taper for patients on long-term therapy to avoid precipitating Addisonian crisis.
• Treatment may be needed for one year or more
Contraindications: Refer to manufacturer's literature
Precautions: Be aware of the patient's Mantoux status and history of peptic ulcer disease. Long-term steroid associated with significant adverse effects including Cushing's syndrome, fluid retention, osteoporosis, hyperkalemia, poor wound healing.
Significant possible interactions: Refer to manufacturer's literature
ALTERNATIVE DRUGS: • Steroids other than prednisone may be used
• One paper reported the use of erythromycin 600 mg/day for 3-4 months after initial control with prednisone
• Antimicrobials if original infection is persistent. Choice depends on the pathogen.
FOLLOW UP PATIENT MONITORING: • Frequent visits, weekly initially
• Emphasize the need to continue the prednisone because of the chance of relapse
• Monitor the lung disease and the side effects of prednisone therapy (Mantoux, monthly CBC, funduscopic exam every 3-6 months)
PREVENTION/AVOIDANCE: Except for prevention of relapse, none known
POSSIBLE COMPLICATIONS: • Bronchiectasis
• Death, but with proper treatment, recovery is usually complete without permanent sequelae
EXPECTED COURSE AND PROGNOSIS: Complete recovery but individual case management is mandatory
MISCELLANEOUS ASSOCIATED CONDITIONS: • Drug-induced pneumonitis
• Paraquat poisoning
• Amiodarone toxicity
• Acebutolol toxicity
• Freebase cocaine pulmonary toxicity
• Overdose of L-tryptophan
• Though most were treated with antibiotics only penicillamine and sulfasalazine have been implicated
• Infections
• Chronic infectious pneumonia
• Malaria
• Immuno-compromise
• Bone marrow transplantation
• Connective tissue diseases
• Rheumatic lung
• Sjogren's syndrome
• Polymyositis
• Scleroderma
• Essential mixed cryoglobulinemia
• Miscellaneous
• Cystic fibrosis
• Bronchopulmonary dysplasia
• Renal failure
• Congestive heart failure
• Adult respiratory distress syndrome
• Chronic eosinophilic pneumonia
• Hypersensitivity pneumonitis
• Histiocytosis X
• Sarcoidosis
• Pneumoconioses
• Radiation pneumonitis
AGE-RELATED FACTORS:
Pediatric: Rare, but has been reported after viral pneumonia (adenovirus influenza). Characteristics include delayed recovery, persistent cough, crackles or wheezing after pneumonia. The laboratory findings are generally not helpful. Imaging shows: V/Qm matched defects; HRCT, bronchiectasis, bronchogram, pruned tree appearance. Diagnosis confirmed by biopsy. Treatment includes steroids - 1 mg/kg/24 hrs for one month, followed by weaning over several months.
Geriatric: Not common
Others: Apparently only seen in adults
PREGNANCY: N/A
SYNONYMS: • Intraluminal fibrosis of distal airways
• Idiopathic BOOP
• Cryptogenic organizing pneumonia (COP)
• Obliterative bronchiolitis
ICD-9-CM: 491.8 Other chronic bronchitis
(see
images)
Want to discuss this term? Visit
our forum or our chat
room.
SEE ALSO (Enter the keywords below
into our search box or click on the link):
Sjogren's syndrome
|
IE 5.0