Bronchiectasis Information

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I thought many might want to read about bronchiectsis....its been in the

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BRONCHIECTASIS

Preview: Although antibiotics and immunizations have greatly reduced the

incidence of bronchiectasis, this confounding and difficult-to-treat

condition continues to cause substantial morbidity. Clinical features overlap

with those of other chronic obstructive lung diseases, and bronchiectasis can

easily be mistaken for asthma or pneumonia, leading to years of inappropriate

treatment.

Bronchiectasis is one of the chronic obstructive pulmonary diseases (COPDs),

defined by the presence of persistent or recurrent airflow limitation.

However, the hallmark of bronchiectasis is sputum overproduction. Strictly

speaking, bronchiectasis is defined as any widening of the bronchi regardless

of the cause. Typical symptoms are fever, pleurisy, and a chronic cough that

produces foul-smelling and occasionally blood-tinged sputum. Unfortunately,

bronchiectasis is often misdiagnosed, and some patients are treated for

presumed asthma or recurrent pneumonia for years because telltale clinical

signs of bronchiectasis are overlooked.

Demographic Characteristics

With the advent of vaccinations and extended-spectrum antibiotics, the

prevalence of bronchiectasis has decreased. It now appears that the condition

is more often linked with congenital disorders than with infections, although

this conclusion remains controversial .

Bronchiectasis caused by infection tends to occur predominantly in

middle-aged to elderly populations, while that associated with congenital

defects is likely to occur in younger patients. In one study (2), the mean

age at injury was found to be 20 years, the mean age at onset of symptoms was

39 years, and the age range with the highest frequency of bronchiectasis was

60 to 80 years. Only 4% of cases were associated with a systemic disorder,

but 70% of patients identified a significant pulmonary insult in their

history before the onset of symptoms. This study also found that

bronchiectasis appeared to be more common in white women and lifetime

nonsmokers than in other populations.

Causes and Classification

The two factors common in all causes of bronchiectasis are intense

inflammation and inadequate host defense mechanisms, particularly with

respect to clearing of mucus. The breakdown in the protective capabilities of

the bronchus allows the inflammatory state to persist. This defect may be

congenital or acquired.

Localized bronchiectasis results from a focal insult, such as severe lobar

pneumonia, followed by persistent weakened defenses in the area of injury.

Generalized, or diffuse, bronchiectasis develops in the context of a global

disorder predisposing to chronic inflammation.

The production and subsequent expectoration of mucus defines clinically

active disease. Bronchial dilation, inflammation, and weakening cause airway

distortion and scarring, which then disrupt airway defense mechanisms and

impair mucociliary clearance. Pooling of secretions follows, complicated by

bacterial colonization and infection. Bronchial inflammation, characterized

by neutrophil infiltration, results in increased protease activity, which in

turn leads to mucus hypersecretion and airway destruction (7). Airway

distortion, sputum production, infection, and inflammation are essential

features of this vicious cycle.

In 1950, Reid described three types of bronchiectasis. Fusiform (cylindrical)

bronchiectasis, the most common type, refers to mildly enlarged bronchi that

fail to taper distally. This type of bronchiectasis can be reversed and may

be seen after acute bronchitis. In varicose bronchiectasis, the bronchial

walls appear beaded, because areas of dilation are mixed with areas of

constriction. Saccular (cystic) bronchiectasis is characterized by severe,

irreversible ballooning of the bronchi peripherally, with or without

air-fluid levels. For practical purposes, this classification system is not

as relevant as the extent of dysfunction of the mucus-clearing mechanism.

Predisposing Conditions

Table 1 lists major and minor predisposing conditions for bronchiectasis,

according to mechanism of initial injury. Severe inflammation can lead to

necrosis of the bronchi focally, as in Mycobacterium tuberculosis or

Mycobacterium avium-intracellulare pneumonia. Diffuse damage can occur in

inflammatory conditions, such as cystic fibrosis and allergic

bronchopulmonary aspergillosis. Airway obstruction, if unrelieved, leads to

accumulation of mucus, distention of the peripheral airways, and infection.

Traction bronchiectasis occurs with any fibrosing process where alveolar

volume loss increases pull on the adjacent bronchial walls, distorts airway

architecture, and enlarges the distal bronchi.

ble 1. Conditions predisposing to bronchiectasis

TABLE 1. Conditions Predisposing to Bronchiectasis

Severe Inflammation

Infection

     1. Mycobacterium species (eg, tuberculosis, avium-intracellulare)

     2. Bacterial (eg, Staphylococcus aureus, Bordetella pertussis)

     3. Viral (eg, measles, influenza, rubeola, adenovirus, HIV)

     3. Fungal (eg, histoplasmosis, aspergillus, coccidioidomycosis)

Hypersensitivity

     1. Allergic bronchopulmonary aspergillosis

Inhalation Injury

     1.Smoke

     2.Sulfur dioxide

     3.Ammonia

Other

     1. Recurrent gastric aspiration

     2. Heroin overdose

     3. Autoimmune disease (eg, relapsing polychondritis, Behçet's syndrome)

     4. Diffuse panbronchiolitis

Congenital Syndromes

     1.Cystic fibrosis

     2.Alpha1-antitrypsin deficiency

     3.Primary Ciliary Dyskinesia or Kartagener's syndrome (situs inversus,

sinusitis,

        and Bronchiectasis )

     4. Immunodeficiency states (eg, hypogammaglobulinemia)

     5. Young's Syndrome (azoospermia and chronic sinopulmonary infections)

     6. Yellow-nail Syndrome (lymphedema, pleural effusions, hypertrophic

nails)

Airway Obstruction

     1.Foreign body

     2. Bronchial stricture

     3. Airway neoplasia or nodule

         1. Bronchogenic carcinoma

         2. Bronchial adenoma

         3. Carcinoid

         4. Sarcoidosis

         5. Amyloidosis

         6. Broncholith

External compression of bronchus

     1. Mediastinal mass or lymph node

     2. Lung cancer

     3. Vascular aneurysm

     4. Mediastinal fibrosis

Traction

Pulmonary Fibrosis

Tuberculosis

Collagen vascular disease

Sarcoidosis

Radiation

Anatomic Malformations or Variants

Bronchomalacia

Bronchial Cartilage Deficiency (- syndrome)

Tracheobronchomegaly (Mounier-Kuhn syndrome)

Unilateral hyperlucent lung (Swyer- syndrome)

Bronchopulmonary sequestration

Middle lobe syndrome

Among the many congenital causes of bronchiectasis, cystic fibrosis and

alpha1-antitrypsin deficiency are the most common. Another congenital cause,

primary ciliary dyskinesia, occurs when the cilia of the respiratory

epithelium are structurally aberrant and move abnormally . Kartagener's

syndrome is a form of primary ciliary dyskinesia defined by the triad of

situs inversus, sinusitis, and bronchiectasis. Humoral immunodeficiency is

associated with bronchiectasis through recurrent infections of the lungs and

sinuses. Finally, certain rare anatomic malformations, such as

tracheobronchomegaly (Mounier-Kuhn syndrome) and middle-lobe syndrome, may

also predispose to bronchiectasis.

Signs and Symptoms

In patients with bronchiectasis, chronic productive cough usually persists

year-round or may occur only after an infection. The cough is worse while the

patient is lying down, since secretions accumulate in dependent areas. The

sputum is often purulent and varies in quantity from 20 to 500 mL per day.

Some types of bronchiectasis, such as that due to M tuberculosis, involve

primarily the upper lobes. Since secretions do not pool, sputum production is

typically normal in these patients, resulting in so-called dry

bronchiectasis  Hemoptysis occurs in about 50% of bronchiectasis patients,

and the volume of blood produced ranges from slight streaking to

life-threatening (rare).

Physical examination can provide clues to the diagnosis. Clubbing is common

in moderate or advanced bronchiectasis and is not seen with other obstructive

lung diseases. If clubbing is found in a patient with airflow obstruction,

non-small cell carcinoma or bronchiectasis should be suspected. Wheezes,

rhonchi, crackles, and a pleural rub are common auscultatory findings. These

sounds may be localized in focal bronchiectasis but tend to be diffuse in

asthma and other types of COPD. lists features of bronchiectasis, asthma, and

chronic bronchitis.

Diagnostic Evaluation

Diagnosis of bronchiectasis usually is gleaned from the history and a

compatible imaging study of the chest. In the appropriate clinical setting,

procedures such as a sweat chloride test, studies of serum immunoglobulins,

and ciliary ultrastructure examination may be needed to rule out a systemic

process. However, if the patient has a clear history of severe lung infection

as a youth and no history of systemic illness, chest radiography may be the

only study needed.

The chest film, which is abnormal in at least 87% of patients with

bronchiectasis, can help eliminate other pulmonary processes. Findings

indicative of bronchiectasis include increased linear markings ( " tram

tracking " ), crowding, cystic spaces, and in severe cases, honeycombing.

Infiltrates are common, especially during an acute exacerbation.

High-resolution CT scanning of the chest has replaced bronchography as the

" gold standard " for detecting bronchiectasis. Classically, cylindrical

bronchiectasis may appear as " signet rings " in transection (the dilated

bronchus is the " ring " and the accompanying pulmonary artery is the " stone " )

or as " tram lines " when the bronchus is cut horizontally. Tram lines may also

be seen in acute bronchitis but tend to occur in the dependent portions of

the lung and clear with resolution of the inflammation.

Varicose bronchiectasis has the appearance of a string of pearls, which

represent cysts separated by constricted areas of the bronchi. Cystic

bronchiectasis, in contrast, looks like clusters of large cysts showing

air-fluid levels. The affected bronchi may also take on a beaded appearance.

Pulmonary function tests usually reveal an obstructive defect defined by a

ratio of forced expiratory volume in 1 second to forced vital capacity

(FEV1/FVC) that is less than 0.8 (2). A concomitant restrictive defect, in

which FVC is less than 80% of the predicted value, may be found. Pulmonary

function test findings are nonspecific and have limited diagnostic value but

are helpful in assessing the response to therapy.

Sputum cultures may guide the choice of antibiotic, because they often reveal

the presence of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus

influenzae, Pseudomonas aeruginosa, gram-negative rods, or Mycobacterium

species. Bronchoscopy may be useful to rule out focal bronchial lesions in

situations of localized disease.

Treatment and Prognosis

Treatment of bronchiectasis generally is aimed at alleviating symptoms.

Management of the underlying predisposing illness is important (eg,

immunoglobulin replacement in humoral deficiency). Use of inhaled

bronchodilators and postural drainage may be helpful. Various devices are

available to assist in mobilizing and clearing airway mucus (eg, flutter

device, intrapulmonic percussive ventilation device, incentive spirometry) .

In addition, patients who have recurrent fevers, dyspnea, or hemoptysis

generally require long-term or intermittent antibiotic therapy. Clinicians

have prescribed broad-spectrum antibiotics, alternating monthly, with

variable success. Cystic fibrosis patients infected with Pseudomonas species

tend to respond to inhaled aminoglycosides such as Tobi or Colymycin.

Patients who have moderate to severe symptoms may require intravenous

antibiotics, usually an aminoglycoside and either an antipseudomonal

penicillin or a third-generation cephalosporin or a fluoroquinolone. Lobar

resection and bilateral lung transplantation are treatments of last resort,

although they are the only truly curative interventions. Lung resection

commonly results in dramatic improvement in symptoms. Uncontrolled hemoptysis

may require bronchial artery embolization or lung resection.

Prognosis varies with the predisposing condition. In general, patients do

well if they comply with treatment regimens and practice routine preventive

strategies, such as avoiding respiratory irritants (eg, tobacco) and

maintaining immunizations for measles, rubeola, pertussis, influenza, and

pneumococcal infections.

Summary

Bronchiectasis belongs to the family of chronic obstructive lung diseases,

even though it is much less common than asthma, chronic bronchitis, or

emphysema. Clinical features of these entities overlap significantly. The

triad of chronic cough, sputum production, and hemoptysis always should bring

bronchiectasis to mind as a possible cause. Chronic airway inflammation leads

to bronchial dilation and destruction, resulting in recurrent sputum

overproduction and pneumonitis.

Once the diagnosis is confirmed, any potential predisposing conditions should

be aggressively sought. The relapsing nature of bronchiectasis can be

controlled with antibiotics, chest physiotherapy, inhaled bronchodilators,

proper hydration, and good nutrition. In rare circumstances, surgical

resection or bilateral lung transplantation may be the only option available

for improving quality of life. Prognosis is generally good but varies with

the underlying syndrome

Becki

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