Sindrome coronario agudo

MED ICA L PR OGR ES S

Review Article

Medical Progress B RONCHIECTASIS
ALAN F. BARKER, M.D.

This affection of the bronchia is always produced by chronic catarrh, or by some other disease attended by long, violent, and often repeated fits of coughing. R.T.H. Laënnec1

B

RONCHIECTASIS is an uncommon disease with the potential to cause devastating illness, including repeatedrespiratory infections requiring antibiotics, disabling productive cough, shortness of breath, and occasional hemoptysis. Landmarks in the history of bronchiectasis include the vivid descriptions of patients with suppurative phlegm that appeared in the writings of René Théophile Hyacinthe Laënnec in the early 19th century; the 1922 introduction by Jean Athanase Sicard of contrast bronchography, whichpermitted the precise imaging of the destructive changes in the airway; the defining studies by Lynne Reid in the 1950s linking bronchography with pathological specimens; and the subsequent decline in prevalence that is probably attributable to effective antituberculous therapy and immunization against pertussis and measles. In this article, I discuss recent developments, including the compounding rolesof infections, amplified inflammatory responses, and defects in host defense; the replacement of bronchography by high-resolution computed tomography (CT) as a definitive imaging tool; and the similarities and differences between bronchiectasis and cystic fibrosis in terms of clinical features and management strategies. Thanks to the work of Reid, the definition of the disease has remainedmorphologic for 50 years: bronchiectasis is the permanent dilatation of bronchi.2 It can be categorized according to the pathological or radiographic appearance of airways. Cylindrical or tubular bronchiectasis is characterized by
From the Pulmonary and Critical Care Division, Department of Medicine, Oregon Health and Science University, Portland. Address reprint requests to Dr. Barker at the Pulmonaryand Critical Care Division, Department of Medicine, Oregon Health and Science University, Portland, OR 97201, or at barkera@ohsu.edu.

dilated airways alone and is sometimes seen as a residual effect of pneumonia; varicose bronchiectasis (so named because its appearance is similar to that of varicose veins) is characterized by focal constrictive areas along the dilated airways that result fromdefects in the bronchial wall; and saccular or cystic bronchiectasis is characterized by progressive dilatation of the airways, which end in large cysts, saccules, or grape-like clusters (this finding is always indicative of the most severe form of bronchiectasis).2 The prevalence of bronchiectasis in the United States and worldwide is unknown. There are reports of high prevalence in relativelyisolated populations with poor access to health care and high rates of respiratory tract infections during childhood, such as Alaskan Natives in the Yukon–Kuskokwim Delta.3
PATHOPHYSIOLOGY

Bronchiectasis is primarily a disease of the bronchi and bronchioles involving a vicious circle of transmural infection and inflammation with mediator release.4 Illness is related to retained inflammatorysecretions and microbes that cause obstruction and damage of the airway and recurrent infection. Although there are no studies of patients in the very early stages of bronchiectasis, findings in patients with proven bronchiectasis give credence to the importance of enhanced cellular and mediator responses: bronchial mucosal biopsies reveal infiltration by neutrophils and T lymphocytes5; expectoratedsputum has increased concentrations of elastase6 and the chemoattractants interleukin-8,7 tumor necrosis factor a (TNF-a),8 and prostanoids.9
FOCAL AND DIFFUSE PRESENTATIONS

Bronchiectasis can present in either of two forms — a local or focal obstructive process of a lobe or segment of a lung or a diffuse process involving much of both lungs and often accompanied by other sinopulmonary...