Restrictive lung disease

Restrictive lung disease
Classification and external resources
ICD-9-CM	518.89
eMedicine	article/301760

Restrictive lung diseases (or restrictive ventilatory defects^[1]) are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion,^[2] resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation. Pulmonary function test demonstrates a decrease in the forced vital capacity.

Pathophysiology

In disorders that are intrinsic to the lung parenchyma, the underlying process is usually pulmonary fibrosis (scarring of the lung).^[3] As the disease progresses, the normal lung tissue is gradually replaced by scar tissue interspersed with pockets of air. This can lead to parts of the lung having a honeycomb-like appearance.

Presentation

The main symptoms are shortness of breath and cough.

Diagnosis

In restrictive lung disease, both forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) are reduced, however, the decline in FVC is more than that of FEV1, resulting in a higher than 80% FEV1/FVC ratio. In obstructive lung disease however, the FEV1/FVC is less than 0.7, indicating that both FEV1 and FVC are reduced. This indicates that the FVC is also reduced, but not by the same ratio as FEV1. ^[4]

One definition requires a total lung capacity which is 80% or less of the expected value.^[5]

Causes and classification

Restrictive lung diseases may be due to specific causes which can be intrinsic to the parenchyma of the lung, or extrinsic to it.^[6]

Intrinsic

• Pneumoconiosis caused by long-term exposure to dusts, especially in mining. For example, Asbestosis.
• Radiation fibrosis, usually from the radiation given for cancer treatment.
• Certain drugs such as amiodarone, bleomycin and methotrexate.
• As a consequence of another disease such as rheumatoid arthritis.
• Hypersensitivity pneumonitis due to an allergic reaction to inhaled particles.
• Acute respiratory distress syndrome (ARDS), a severe lung condition occurring in response to a critical illness or injury.
• Infant respiratory distress syndrome due to a deficiency of surfactant in the lungs of a baby born prematurely.
• Tuberculosis^[7]

Many cases of restrictive lung disease are idiopathic (have no known cause). Still, there is generally pulmonary fibrosis.^[3] Examples are:

• Idiopathic pulmonary fibrosis
• Idiopathic interstitial pneumonia, of which there are several types
• Sarcoidosis
• Eosinophilic pneumonia
• Lymphangioleiomyomatosis
• Pulmonary Langerhans' cell histiocytosis
• Pulmonary alveolar proteinosis

Conditions specifically affecting the interstitium are called interstitial lung diseases.

Extrinsic

• Nonmuscular diseases of the upper thorax such as kyphosis, pectus carinatum and pectus excavatum.^[8]
• Diseases restricting lower thoracic/abdominal volume (e.g. obesity, diaphragmatic hernia, or the presence of ascites).^[8]
• Pleural thickening.

See also

• Chronic obstructive pulmonary disease
• Obstructive lung disease

References

1. Johns Hopkins School of Medicine's Interactive Respiratory Physiology > Restrictive Ventilatory Defect Retrieved on February 25, 2010
2. Sharma, Sat. "Restrictive Lung Disease". Retrieved 2008-04-19.
3. PULMONARY FUNCTION TESTS A Workshop on Simple Spirometry & Flow Volume Loops. Dr. S. Osborne, Dept. Cellular & Physiological Sciences. Mars 2009
4. Lee, H., Lim, S., Kim, J., Ha, H., & Park, H. (2015). Comparison Of Various Pulmonary Function Parameters In The Diagnosis Of Obstructive Lung Disease In Patients With Normal Fev1/FVC And Low FVC. American Journal Of Respiratory And Critical Care Medicine, 191, American Journal Of Respiratory And Critical Care Medicine, 2015, Vol.191.
5. Brack T, Jubran A, Tobin MJ (May 2002). "Dyspnea and decreased variability of breathing in patients with restrictive lung disease". Am. J. Respir. Crit. Care Med. 165 (9): 1260–4. doi:10.1164/rccm.2201018. PMID 11991875.
6. "eMedicine - Restrictive Lung Disease : Article by Sat Sharma". Retrieved 2008-11-21.
7. Amaral, André F.S.; Coton, Sonia; Kato, Bernet; Tan, Wan C.; Studnicka, Michael; Janson, Christer; Gislason, Thorarinn; Mannino, David; Bateman, Eric D.; Buist, Sonia; Burney, Peter G.J. (October 2015). "Tuberculosis associates with both airflow obstruction and low lung function: BOLD results". European Respiratory Journal. 46 (4): 1104–1112. doi:10.1183/13993003.02325-2014. PMID 26113680.
8. eMedicine Specialties > Pulmonology > Interstitial Lung Diseases > Restrictive Lung Disease Author: Lalit K Kanaparthi, MD, Klaus-Dieter Lessnau, MD, Sat Sharma, MD. Updated: Jul 27, 2009