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PULMONARY CROHNS DISEAS
– Recognized before, after or conmarch_03ly with the onset of bowel disease.
– Most commonly seen after onset of GI symptoms.
– Course and severity of pulmonary disease not necessarily related to activity of intestinal disease.

Types of involvement:
– Acute alveolitis
– Chronic bronchitis
– Bronchiectasis
– Brochiolitis obliterans with organizing pneumonia
– Obstructive disease
– Bronchial hyperresponsiveness
– Interstitial pneumonitis/ fibrosis
– Granulomatous lung disease
– Inflammatory tracheal stenosis
– Lung infiltrates with peripheral eosinophilia
– Pulmonary vasculitis

Typical acute presentation and findings:
– Cough and breathlessness
– Obstructive lung disease of variable severity
– Sometimes restrictive pattern
– Slight or inconsistent response bronchodilators
– CXR often normal
– Decreased DLco
– Increased FRC and RV
– Increased bronchial reactivity
– Alveolar lymphocytosis

DLco is typically reduced in acute presentation:
– Reduction greater with exacerbation than in remission 1-3
– Related to disease activity 1, 3
– Not related to disease activity 4
– Not related to disease severity 2
– Not related to disease severity or activity 5-7

FRC and not DLco affected in acute presentation:
– FRC elevated and associated with disease activity 5
– FRC elevated and associated with disease severity 8

Differential diagnosis
The main differential diagnosis is extrapulmonary, intestinal involvement of sarcoid
– Non-caseating epitheloid granulomas
– Tendency to fibrosis
– Erythema nodosum, arthritis, uveitis
– Biopsy to diagnose
– Serum ACE may be used to monitor but not good for diagnosis
– Kveim test is no longer in practice
– Families exist in which sarcoid and crohns disease conditions coexist. This plus the similarities of the two conditions suggest the possibility of a similar genetic predisposition

Outcome
– Steroid responsive
– Pattern and site of involvement usually remain same over time
– Change in degree of activity over time
– Note that colonic and bronchial epithelium are both derived from the primitive gut
– Respiratory manifestations may develop if GI symptoms controlled or post coloproctectomy
– Coloproctectomy does not improve respiratory symptoms

Latent Pulmonary changes that are seen in crohns disease
– Alveolar lymphocytosis
– Activation alveolar macrophages (superoxide generation)
– Low T1/2 DTPA clearance lungs
– Increased pulmonary vascular permeability
– Abnormal PFTs

WHAT IS THE CLINICAL SIGNIFICANCE OF THESE FINDINGS?


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