Pneumonitis (ILD), acute and/or severe (may cause ARDS)

(Fr: PINS aiguë). Acute, generally bilateral and diffuse pneumonitis. More rapid in onset and/or denser, more extensive and severe than pattern Ib. Can be fulminate in the form of diffuse pulmonary interstitial or alveolar opacities and the ARDS picture (see under IIb). BAL is generally lymphocytic and is also indicated to rule out pneumonia due to Pneumocystis, BCG, viruses or other agents particularly in the immunodepressed. Pathology (lung biopsy is not necessary in the majority; before going for the biopsy, please look at PMID 25950989) may disclose dense NSIP, widespread granulomas, or OP depending both on patient and drug. In severe cases pulmonary edema, DAD and/or DAH may develop. Corticosteroid therapy is indicated if patients progress to acute respiratory failure, once an infection has been carefully and resonably ruled out. Transition to pulmonary fibrosis is very uncommon. The boundary between patterns Ia and Ib may be difficult to delineate. See also under IIb

Last update : 01/01/1970

Causative drugs


Tryptophan (l-tryptophan, synthetic)



I.a I - Interstitial/parenchymal lung disease
I.a - Pneumonitis (ILD), acute and/or severe (may cause ARDS)
I.b I - Interstitial/parenchymal lung disease
I.b - Pneumonitis (ILD)
I.c I - Interstitial/parenchymal lung disease
I.c - Eosinophilic pneumonia (pulmonary infiltrates and eosinophilia)
I.d I - Interstitial/parenchymal lung disease
I.d - Organizing pneumonia pattern (an area or areas of consolidation on imaging)
I.k I - Interstitial/parenchymal lung disease
I.k - Lung nodule or nodules
II.b II - Pulmonary edema - Acute lung injury - ARDS
II.b - ARDS - Acute lung injury
IV.c IV - Airway involvement
IV.c - Obliterative bronchiolitis (a pattern consistent with) (see also IVn, XVx)
VIII.aq VIII - Central-large-upper airway (incl. pharyngeal-nasal) involvement
VIII.aq - Bronchorrhea
X.g X - Systemic/Distant conditions, syndromes and reactions
X.g - Hypersensitivity reaction (may manifest with fever and/or skin, throat or airway involvement)
X.o X - Systemic/Distant conditions, syndromes and reactions
X.o - Neutrophilic dermatosis (Pyoderma, Sweet syndrome)
XV.b XV - Pathology
XV.b - Path: Eosinophilic pneumonia (subacute or acute) (see also Ic)
XV.c XV - Pathology
XV.c - Path: Organizing pneumonia (OP/BOOP) pattern (see also Id)
XV.e XV - Pathology
XV.e - Path: ILD with a granulomatous component (see also Im)
XV.x XV - Pathology
XV.x - Path: Acute/subacute bronchiolitis (see also IVc, IVi)
XV.cn XV - Pathology
XV.cn - Path: Pulmonary necrotizing granuloma with neutrophilic microabscesses
XVI.g XVI - Imaging
XVI.g - Imaging: Diffuse whiteout/alveolar shadowing (see also under IIb-ARDS)
XVI.v XVI - Imaging
XVI.v - Imaging: Centrilobular micronodules (can be diffuse)
XVII.a XVII - Infections & related conditions
XVII.a - Respiratory tract infection incl. pneumonia
XVII.v XVII - Infections & related conditions
XVII.v - Strongyloides stercoralis hyperinfection (w/wo DAH)