Wednesday, May 6, 2009

Bronchiectasis

-Etiology:

*Less than 40% of patients with bronchiectasis will have an obvious cause for their condition and the majority will be classified as idiopathic

*Conditions associated with bronchiectasis:

Infections (acquired causes)

o Pertussis à infection (necrotizing bronchitis and permanent infection due to impaired 1ry lung defenses) + obstruction (by endobronchial debris and mucus à small peripheral areas of collapse).

o Measles à infection and inflammation

o Adenovirus 21

o Pneumonia (precede bronchiectasis or after viral infections)

O Tuberculosis (upper lobe bronchiectasis): by 1ry complex or Brake's syndrome.

O Aspergillosis (mainly allergic ABPA) à proximal bronchi obstruction either extra luminal or intra luminal (see fungal infection)

o Mycobacterium avium complex (MAC)

o HIV infection

Immune dysfunction (immunodeficiency)

o Primary and secondary immunoglobulin deficiency

o Complement deficiency

o Chronic granulomatous disease

Other inherited diseases

à Metabolic Defects:

o Cystic fibrosis (see CF chapter)

o 1- antitrypsin deficiency (causes emphysema alone or with bronchiectasis or with chronic bronchitis).

à Gross Structural defects:

O Williams-Campbell syndrome (AR bronchomalacia due to defective or complete absence of cartilage in walls of bronchi from 4th-8th generation à mechanical abnormality and recurrent diffuse pneumonias à bronchiectasis).

o Swyer-James syndrome (unilateral hyper lucent lung) (see COPD)

o Mounier-Kuhn syndrome (tracheo-bronchomegally; cartilaginous enlargement of the rings of trachea and its divisions up to segmental bronchi à LRTI mainly diffuse pneumonias ± symptoms of Ehler Danlos syndrome).

O Yellow nail syndrome (premalignant state of lymphatic hyperplasia) à ♂ = ♀

*Ccc:

a. Lymphoma and Carcinoma

b. Lymph edema

c. Dystrophic nail changes à thickened, curved, with longitudinal and transverse ridges, with yellow brown pigmentations and grow slower than normal.

d. Pleural effusion (usually small)

e. Bronchiectasis

f. Protein losing entropathy

o Intra-pulmonary lung Sequestration (partial pulmonary agenesis à bronchi are dilated with no evidence of alveoli mostly in posterior basal segment left lower lobe with systemic blood supply from aorta and drain in right atrium with its own pleura; they only communicate with the surrounding lung tissue when complicated or ruptured) à (Extra-lobar sequestration present in infancy with respiratory distress and chronic cough; some lesions are diagnosed coincidentally. Intrapulmonary sequestration is usually diagnosed later in childhood or adulthood when the patient presents with an infection à with associated abnormalities of 50%: Diaphragmatic hernia, pectus excavatum, tracheo­esophageal fistula esophageal duplication, esophageal cyst, bronchogenic cyst, megacolon and congenital heart disease are the most common à can cause polyhydramnios and hydrops fetalis in utero) à recurrent focal pneumonias.

.N.B. all can cause bronchiectasis by repeated 2ry bacterial infections.

Clearance defects (ultra-structural defects)

à Immotile cilia syndrome (1ry ciliary dyskinesia):

o Kartagener's syndrome (> one gene responsible for defect in cilia structure by failure of coordinated sliding and binding of cilia either due to absence of dynen arms or radial spokes; or presence of special transposition of microtubules à abnormal mucus transport from bronchial tree to the mouth à impaired defenses):

*Ccc:

a. Recurrent sinusitis ± chronic rhinorrhea and otitis media (mild deafness)

b. Male infertility (immotile live sperms)

c. LRTI (recurrent diffuse pneumonias) à chronic cough and acquired bronchiectasis.

d. Dextrocardia (situs inversus totalis in 1/2 cases)

*Diagnosed by:

a. History of repeated infections and previous ccc

b. Nasal mucosal biopsy à ultra-structural defect by high speed digital video photography.

c. Saccharine test à abnormal mucociliary movement (normally from 10-15mins, >28 mins means permanent damage à place a small particle of saccharin approximately 1 cm behind the anterior end of the inferior turbinate. In the presence of normal mucociliary action, the saccharin will be swept backwards to the nasopharynx and a sweet taste perceived).

d. E.M. à for sperm tails and ciliary movement.

o Young's syndrome (idiopathic obstructive azospermia, defect in ciliary function with unknown mechanism):

*Ccc:

a. Azospermia (due to obstruction in vas deferens)

b. Poorly motile sperms in epididymis (not in ejaculate)

c. Severe chest disease (1/2 cases) and bronchiectasis (1/5 cases).

Others (acquired causes)

o Rheumatoid arthritis (collagen disorder)

o SLE (collagen disorder)

o Sjogren's syndrome (AI disease)

o Ulcerative colitis (AI disease)

o Crohn's disease (AI disease)

o Celiac disease (AI disease)

o 1ry biliary cirrhosis (AI disease)

o Pernicious anemia (AI disease)

o Thyroiditis (AI disease)

o Toxic chemical inhalation (Cl, NH3)

o Inhaled gastric contents or GERD

o Heroin

o Foreign body (intraluminal obstruction à 2ry infection)

o Pulmonary fibrosis

o Absence of bronchial cartilage

-Treatment:

[A] General management:

1. Stop smoking

2. Avoid 2nd hand smoke

3. Adequate nutritional supplementations

4. Immunization against H. influenza, Pneumococcal pneumonia

5. MMR, Pertussis immunization

6. O2 therapy when needed up to IPPV

7. Psychotherapy sometimes needed for children

[B] Medical management: (relieve and control symptoms)

1. Control infection "Antibiotics":

· Given for: 7-15ds

· Choice according to:

a. Penetration of the antibiotic to the thick secretions and walls.

b. Specificity to organisms.

c. Severity of infection so that:

o Mild exacerbation à Amoxicillin (250mg tds), Sutrim, Azathioprine, 2nd generation cephalosporins or Quinolones.

o Moderate to Severe (purulent) à Aminoglycosides, antipseudomonal Penicillins, Fluoroquinolones or 3rd generation cephalosporins, Clindamycin in anaerobic infections, Tobramycin inhalation with CF or combination of clarithromycin, rifampicin, ethambutol ± streptomycin in MAC for 18-24 Ms till culture –ve.

· Response: known by improvement of symptoms and PFT.

· Prophylaxis: was given in the form of 2gm tetracycline twice/wk for 1year or only in winter; aiming to decrease inflammation, prevent further destruction and fibrosis, and decrease frequency of exacerbations; but it proved to develop resistance and more colonization of pseudomonas and klebsiella beside being expensive and having multiple side effects.

2. Remove secretions:

a. Postural drainage therapy (Tipping): à mainstay for treatment

· Definition: It's the force of gravity support and external manipulation of the thorax to drain retained secretions (pt expectorates >30ml sputum/d) due to lost cartilage and lost cilia with the presence of changes in epithelial and mucosal linings.

· Value:

i. Increase rate of mucociliary clearance.

ii. Improve the mobilization of bronchial secretions especially copious ones.

iii. Improve airway function (normalize FRC).

iv. Improve the matching of ventilation and perfusion.

· Draining positions: Leaning forward if basal; and supine with elevated legs with the affected side lifted off bed by a pillow if in the middle lobe or lingula.

· Techniques:

i. Postural drainage à patient takes deep breathes followed by coughing for 10-15 mins in the previous positions mentioned.

ii. Percussion can be used "Ketchup bottle method".

iii. Huffing Technique (forced expiratory technique) (CB4)

iv. High frequency chest wall compression

v. High frequency mouth oscillation

vi. Devices use for drainage:

o Vest system (pneumatic compression device)

o Flutter devices

o Intrapulmonic percussive ventilation devices

o Incentive spirometry

o Biphasic cuirass ventilator

· Frequency: in stable states done once daily but in acute exacerbations frequency is increased to several times/d each till chest is apparently dry.

b. Mucolytics:

o Pulmozyme à DNA cleaving enzyme that decreases viscosity of secretions with 6% improvement in FEV1 and decrease in the incidence of exacerbations and hospital admissions and stay.

o N. acetyl cysteine à develops BS so not usually used.

o Amiloride à Na channel blocker inhaled to change the electrical composite in sputum of pts with CF to decrease viscosity.

o Recombinant human DNase à disrupts sputum DNA debris and decreases viscosity.

o Nebulized Saline à hydrate and decrease viscosity.

3. Brochodilate:

a. B2 agonists à improve FEV1 and increase clearance of secretions when given before physiotherapy.

b. Corticosteroids à given when no response occurs to B2 agonists in stable phase, in acute exacerbations and in ABPA to decrease inflammation à 30-40mg/d of prednisolone or inhalation of beclomethazone or 750 mcg /12hrs for 10 ds

4. Treat the cause and complications

Immunoglobulins: are used in cases of immunodeficiency with recurrent respiratory tract infections à 200mg/Kg IV every 2wks or 400 mg/Kg every 4 wks à can cause anaphylaxis which is prevented by giving hydrocortisone IV before the 1st 3 infusions with slowing the rate of infusion.

5. Surgical management

*For Full Text --> Download from: Bronchiectasis.doc

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