interstitial lung disease; diffuse parenchymal lung disease (DPLS, ILD)
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Introduction
Interstitial lung diseases are a heterogenous group of disorders.
'diffuse parenchymal lung disease' may be a more appropriate term since these diseases are NOT restricted to the pulmonary interstitium, & not all interstitial tissue is necessarily affected[2]
Etiology
- occupational or environmental inhalants
- drugs
- radiation (6 weeks to months after radiation therapy)
- infections (interstitial pneumonia)
- viral, bacterial, fungal, parasites
- non-specific interstitial pneumonia
- lymphocytic interstitial pneumonia
- hypersensitivity pneumonitis
- pulmonary edema
- neoplasms
- metabolic causes
- sarcoidosis
- idiopathic pulmonary pneumonitis
- connective tissue disease
- pulmonary vasculitis
- pulmonary hemorrhage
- eosinophilic granuloma
- pulmonary alveolar proteinosis
- amyloidosis
- pulmonary veno-occlusive disease
- microlithiasis
- inherited disorders
- lymphangioleiomyomatosis
- bronchiolitis obliterans
- respiratory bronchiolitis
- chronic eosinophilic pneumonia
- smoking-related
- pulmonary Langerhans cell granulomatosis
- desquamative interstitial pneumonia
- respiratory bronchiolitis-associated interstitial lung disease
- smoking-related interstitial fibrosis
- chronic pulmonary aspiration
Pathology
- varying degrees of inflammation & fibrosis
- irreversible disruption of alveolar architecture & impaired gas exchange
- no evidence of granulomatous or vascular disease in the pulmonary parenchyma
Clinical manifestations
- insidious onset with progressive course (> 6 months)
- subacute to chronic
- exertional dyspnea, breathlessness
- non-productive cough
- acute presentation with fever suggests BOOP, drug-induced pulmonary injury or hypersensitivity pneumonitis
- crackles
- fibrosing interstitial lung disease
- idiopathic pulmonary fibrosis
- less common in sarcoidosis
- mid-inspiratory squeaks: bronchiolitis
- signs of pulmonary hypertension
- increased intensity of P2 heart sound
- right ventricular lift
- pansystolic murmur of tricuspid regurgitation
- clubbing
- erythema nodosum
- maculopapular exanthem
- uveitis &/or conjunctivitis
- lacrimal gland or salivary gland enlargement
- lymphadenopathy, hepatomegaly
- arthritis
- connective tissue disease
- inflammatory bowel disease
- sarcoidosis
- Behcet's syndrome
- ankylosing spondylitits
- muscle weakness or myalgias: polymyositis
- neurologic signs/symptoms
- interstitial lung diseases that can present acutely
Laboratory
- arterial blood gas: variable
- complete blood count (CBC)
- chemistry panel (chem7)
- erythrocyte sedimentation rate (ESR) & serum C-reactive protein
- serology (suspicion of rheumatologic disease)
- myositis panel
- serum BNP
- urinalysis[2]
* also see ARUP consult []
Diagnostic procedures
- pulmonary function tests
- variable, but often restrictive pattern
- reduced DLCO
- abnormal alveolar-arterial oxygen gradient at rest or with exertion
- airflow obstruction with or without restriction suggests:
- tissue diagnosis generally not necessary with high-resolution CT[2]
- fiberoptic bronchoscopy
- open lung biopsy
- obtain tissue for pathology prior to initiation of:
- histology must be interpreted with architectural pattern from radiology, laboratory data & clinical findings
- echocardiogram[2] (pulmonary artery pressure)
- exercise stress testing (physiologic response to exercise)
- SaO2 desaturation > 4% with ambulation[2]
Radiology
- non-contrast high resolution computed tomography (CT) of chest
- imaging procedure of choice[2]
- gold standard for evaluation of interstitial lung disease
- more sensitive & specific for diagnosis of interstitial lung disease than chest X-ray
- little role for conventional CT (5 mm slice)[2]
- pseudoreticulation is a false-positive finding due to atelectasis in gravity-dependent lung regions
- mediastinal &/or hilar lymphadenopathy with sarcoidosis
- pleural effusion (asbestosis, connective tissue disease)
- pleural plaques (asbestosis)
- obtain prior to lung biopsy
- imaging procedure of choice[2]
- chest radiograph:
- variable -> bilateral infiltrates
- not predictive of specific pathologic picture, thus of limited utility[2]
- a normal chest X-ray does not rule out diffuse parenchymal lung disease[2]
- predominantly upper lobe interstitial infiltrates
- predominantly lower lobe infiltrates
- bilateral hilar lymphadenopathy suggests sarcoidosis
Complications
- acute respiratory worsening is most often a result of infection or edema[2]
Management
- treat underlying etiology if known
- assessment for connective tissue disease
- serial evaluation of disease activity:
- progression of disease
- effects of therapy
- inhaled treprostinil improves exercise capacity from baseline, assessed by a 6-minute walk test in patients with pulmonary hypertension due to interstitial lung disease[10]
- supplemental O2 >=15 hours/day when hypoxemia (SaO2 <=88% on room air)[9]
- ambulatory oxygen therapy if exertional hypoxemia[9]
- portable liquid oxygen is best
- pulmonary rehabilitation
- evidence for use of glucocorticoids is weak[2]
- lung transplantation for younger patients with severe restrictive lung disease
More general terms
More specific terms
- bronchiolitis obliterans; constrictive bronchiolitis; cryptogenic organizing pneumonia; bronchiolitis obliterans with organizing pneumonia (BOOP)
- drug-induced interstitial lung disease
- eosinophilic pneumonia; Andrews syndrome; pulmonary eosinophilia
- hypersensitivity pneumonitis; extrinsic allergic alveolitis; pigeon breeder's lung; bird fancier's lung; farmer's lung; allergic pneumonitis
- interstitial pneumonia
- occupational lung disease
- pleuroparenchymal fibroelastosis
- pulmonary fibrosis
- pulmonary interstitial emphysema
- respiratory bronchiolitis associated interstitial lung disease; desquamative interstitial pneumonia (RBILD)
Additional terms
- familial hypocalciuric hypercalcemia
- glycogen storage disease (glycogenosis)
- Hermansky-Pudlak syndrome
- lymphangioleiomyomatosis
- neurofibromatosis (von Recklinghausen's disease)
- pulmonary aspiration; foreign body aspiration
- sarcoidosis
- tuberous sclerosis (Bourneville disease, epiloia)
References
- ↑ Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 253-56
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 Medical Knowledge Self Assessment Program (MKSAP) 11, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2009, 2012, 2015, 2018, 2022.
Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022 - ↑ Connors GR, Christopher-Stine L, Oddis CV, Danoff SK Interstitial lung disease associated with the idiopathic inflammatory myopathies: what progress has been made in the past 35 years? Chest. 2010 Dec;138(6):1464-74. doi:http://dx.doi.org/ 10.1378/chest.10-0180. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21138882
- ↑ Antoniou KM, Margaritopoulos GA, Tomassetti S et al Interstitial lung disease. Eur Respir Rev. 2014 Mar 1;23(131):40-54. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/24591661 Free Article
- ↑ Suliman S, Al Harash A, Roberts WN, Perez RL, Roman J. Scleroderma-related interstitial lung disease. Respir Med Case Rep. 2017 Jul 15;22:109-112. PMID: https://www.ncbi.nlm.nih.gov/pubmed/28761806 Free PMC Article
- ↑ Walsh SL, Hansell DM. High-resolution CT of interstitial lung disease: a continuous evolution. Semin Respir Crit Care Med. 2014 Feb;35(1):129-44. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/24481766
- ↑ Meyer KC. Diagnosis and management of interstitial lung disease. Transl Respir Med. 2014 Feb 13;2:4. eCollection 2014. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/25505696 Free PMC Article
- ↑ ARUP Consult: Interstitial Lung Diseases The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/interstitial-lung-diseases
- ↑ 9.0 9.1 9.2 Jacobs SS, Krishnan JA, Lederer DJ, et al. Home Oxygen Therapy for Adults with Chronic Lung Disease. An Official American Thoracic Society Clinical Practice Guideline Am J Respir Crit Care Med. 2020 Nov 15;202(10):e121-e141 PMID: https://www.ncbi.nlm.nih.gov/pubmed/33185464 https://www.atsjournals.org/doi/full/10.1164/rccm.202009-3608ST
- ↑ 10.0 10.1 Waxman A, Restrepo-Jaramillo R, Thenappan T et al Inhaled Treprostinil in Pulmonary Hypertension Due to Interstitial Lung Disease. N Engl J Med 2021. Jan 13, PMID: https://www.ncbi.nlm.nih.gov/pubmed/33440084 https://www.nejm.org/doi/full/10.1056/NEJMoa2008470
Taichman DB Optimism for Interstitial Lung Disease-Associated Pulmonary Hypertension? N Engl J Med 2021. Jan 13, PMID: https://www.ncbi.nlm.nih.gov/pubmed/33440083 https://www.nejm.org/doi/full/10.1056/NEJMe2033181 - ↑ NEJM Knowledge+