1
Forth stage
Medicine
Lec-3
.د
رامي
1/1/2014
Bronchiectasis
Bronchiectasis means abnormal dilatation of the bronchi. Chronic suppurative airway
infection with sputum production, progressive scarring and lung damage are present,
whatever the cause.
Aetiology and pathogenesis
:
Bronchiectasis may result from a congenital defect affecting airway ion transport or ciliary
function, such as cystic fibrosis or be acquired secondary to damage to the airways by a
destructive infection, inhaled toxin or foreign body. The result is chronic inflammation and
infection in airways.
Causes of bronchiectasis:
A) Congenital :
Cystic fibrosis
Ciliary dysfunction syndromes
Primary ciliary dyskinesia (immotile cilia syndrome)
Kartagener's syndrome (sinusitis and transposition of the viscera )
Primary hypogammaglobulinaemia
B) Acquired: children:
Pneumonia (complicating whooping cough or measles)
Primary TB
Inhaled foreign body
C) Acquired: adults
Suppurative pneumonia
Pulmonary TB :is the most common cause worldwide.
Allergic bronchopulmonary aspergillosis complicating asthma
Bronchial tumours
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Clinical features:
Physical signs in the chest may be unilateral or bilateral. If the bronchiectatic airways
do not contain secretions and there is no associated lobar collapse, there are no
abnormal physical signs. When there are large amounts of sputum in the bronchiectatic
spaces, numerous coarse crackles may be heard over the affected areas. Collapse with
retained secretions blocking a proximal bronchus may lead to locally diminished breath
sounds, while advanced disease may lead to scarring and overlying bronchial breathing .
Symptoms of bronchiectasis
:
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) Cough:Chronic productive cough due to accumulation of pus in dilated bronchi;
usually worse in mornings and often brought on by changes of posture. Sputum often
copious and persistently purulent in advanced disease. Halitosis is a common
accompanying feature
.
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) Pneumonia and pleurisy :Due to inflammatory changes in lung and pleura
surrounding dilated bronchi when spread of infection occurs: fever ,malaise and
increased cough and sputum volume, which may be associated with pleurisy. Recurrent
pleurisy in the same site often occurs in bronchiectasis
.
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) Haemoptysis :Can be slight or massive and is often recurrent. Usually associated with
purulent sputum or an increase in sputum purulence. Can, however, be the only
symptom in so-called 'dry bronchiectasis .‘
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) Poor general health:When disease is extensive and sputum persistently purulent,
there may be associated weight loss, anorexia ,lassitude, low-grade fever, and failure to
thrive in children. In these patients, digital clubbing is common
.
Investigations:
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) Bacteriological and mycological examination of sputum
:
In addition to common respiratory pathogens, sputum culture may reveal
Pseudomonas aeruginosa, fungi such as Aspergillus and various mycobacteria. Frequent
cultures are necessary to ensure appropriate treatment of resistant organisms .
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) Radiological examination
Bronchiectasis, unless very gross, is not usually apparent on a chest X-ray. In
advanced disease, thickened airway walls, cystic bronchiectatic spaces, and associated
areas of pneumonic consolidation or collapse may be visible. CT is much more sensitive,
and shows thickened dilated airways.
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3
) Assessment of ciliary function :
A screening test can be performed in patients suspected of having a ciliary
dysfunction syndrome by measuring the time taken for a small pellet of saccharin placed
in the anterior chamber of the nose to reach the pharynx, when the patient can taste it.
This time should not exceed 20 minutes but is greatly prolonged in patients with ciliary
dysfunction. Ciliary beat frequency may also be assessed using biopsies taken from the
nose. Structural abnormalities of cilia can be detected by electron microscopy
Management
:
In patients with airflow obstruction, inhaled bronchodilators and corticosteroids
should be used to enhance airway patency .
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) Physiotherapy :
Patients should be instructed on how to perform regular daily physiotherapy to assist
the drainage of excess bronchial secretions. Efficiently executed, this is of great value
both in reducing the amount of cough and sputum and in preventing recurrent episodes
of bronchopulmonary infection. Patients should adopt a position in which the lobe to be
drained is uppermost. Deep breathing followed by forced expiratory man[oelig ]uvres
(the 'active cycle of breathing' technique) is of help in moving secretions in the dilated
bronchi towards the trachea, from which they can be cleared by vigorous coughing.
'Percussion' of the chest wall with cupped hands may help to dislodge sputum, but does
not suit all patients. Devices which increase airway pressure, either by a constant
amount (positive expiratory pressure mask) or in an oscillatory manner (flutter valve),
aid sputum clearance in some patients, and a variety of techniques should be tried to
find one that suits the individual. The optimum duration and frequency of physiotherapy
depend on the amount of sputum, but 5-10 minutes once or twice daily is a minimum
for most patients .
2)Antibiotic therapy :
For most patients with bronchiectasis, the appropriate antibiotics are the same as
those used in COPD; however, in general, larger doses and longer courses are required,
while resolution of symptoms is often incomplete. When secondary infection occurs
with staphylococci and Gram-negative bacilli, in particular Pseudomonas species,
antibiotic therapy becomes more challenging and should be guided by the
microbiological sensitivities. For Pseudomonas, oral ciprofloxacin (250-750 mg 12-
hourly) or ceftazidime by intravenous injection or infusion (1-2 g 8-hourly) may be
required. Haemoptysis in bronchiectasis often responds to treating the underlying
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infection, although in severe cases percutaneous embolisation of the bronchial
circulation by an interventional radiologist may be necessary .
3)Surgical treatment :
Excision of bronchiectatic areas is only indicated in a small proportion of cases. These
are usually young patients in whom the bronchiectasis is unilateral and confined to a
single lobe or segment on CT. Unfortunately, many of the patients in whom medical
treatment proves unsuccessful are also unsuitable for surgery because of either
extensive bronchiectasis or coexisting chronic lung disease. In progressive forms of
bronchiectasis, resection of destroyed areas of lung which are acting as a reservoir of
infection should only be considered as a last resort .
Prognosis :
The disease is progressive when associated with ciliary dysfunction and cystic fibrosis,
and eventually causes respiratory failure. In other patients the prognosis can be
relatively good if physiotherapy is performed regularly and antibiotics are used
aggressively .
Prevention
:
As bronchiectasis commonly starts in childhood following measles ,whooping cough or
a primary tuberculous infection, it is essential that these conditions receive adequate
prophylaxis and treatment. The early recognition and treatment of bronchial obstruction
is also important
Cystic fibrosis
:
Cystic fibrosis (CF) is the most common fatal genetic disease in Caucasians, with
autosomal recessive inheritance, a carrier rate of 1 in 25 and an incidence of about 1 in
2500 live births .CF is the result of mutations affecting a gene on the long arm of
chromosome 7 which codes for a chloride channel known as cystic fibrosis
transmembrane conductance regulator (CFTR), that influences salt and water movement
across epithelial cell membranes. The genetic defect causes increased sodium and
chloride content in sweat and increased resorption of sodium and water from
respiratory epithelium. Relative dehydration of the airway epithelium is thought to
predispose to chronic bacterial infection and ciliary dysfunction, leading to
bronchiectasis. The gene defect also causes disorders in the gut epithelium, pancreas,
liver and reproductive tract
.
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Clinical features
The lungs are macroscopically normal at birth, but bronchiolar inflammation and infections
usually lead to bronchiectasis in childhood. At this stage, the lungs are most commonly
infected with Staphylococcus aureus; however, many patients become colonised with
Pseudomonas aeruginosa by the time they reach adulthood. Recurrent exacerbations of
bronchiectasis, initially in the upper lobes but subsequently throughout both lungs, cause
progressive lung damage resulting ultimately in death from respiratory failure.Most men
with CF are infertile due to failure of development of the vas deferens, but microsurgical
sperm aspiration and in vitro fertilisation are now possible. Genotype is a poor predictor of
disease severity in individuals; even siblings with matching genotypes may have quite
different phenotypes. This suggests that other 'modifier genes', as yet unidentified,
influence clinical outcome .
Complications of cystic fibrosis:
Respiratory
:
Infective exacerbations of bronchiectasis,Spontaneous pneumothorax,Haemoptysis,Nasal
polyps,Respiratory failure,Cor pulmonale,Lobar collapse due to secretions
.
Gastrointestinal :
Malabsorption and steatorrhoea,Distal intestinal obstruction syndrome
,Biliary cirrhosis and portal hypertension,Gallstones
Others
: Diabetes
(
25
%
of adults),Delayed puberty,Male infertility,Stress incontinence due
to repeated forced cough ,Psychosocial problems,Osteoporosis,Arthropathy,Cutaneous
vasculitis .
Management:
Treatment of CF lung disease
:
The management of CF lung disease is that of severe bronchiectasis. All patients with CF
who produce sputum should perform regular chest physiotherapy ,and should do so more
frequently during exacerbations. While infections with Staph. aureus can often be managed
with oral antibiotics, intravenous treatment
( often self-administered at home through a
subcutaneous vascular port) is usually needed for Pseudomonas species. Regular nebulised
antibiotic therapy
( colomycin or tobramycin) is used between exacerbations in an attempt
to suppress chronic Pseudomonas infection .
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Treatments that may reduce chest exacerbations and/or improve lung function in CF
Nebulised recombinant human DNase 2.5 mg daily used in patient Age ≥ 5, FVC
>
44
%
predicted
Nebulised tobramycin 300 mg 12-hourly ,given in alternate months used in Patients
colonised with pseudomonas aeruginosa
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) Regular oral azithromycin 500 mg three times/week used in Patients colonised with
Pseudomonas aeruginosa
.
Unfortunately, the bronchi of many CF patients eventually become colonised with
pathogens which are resistant to most antibiotics. Resistant strains of P. aeruginosa,
Stenotrophomonas maltophilia and Burkholderia cepacia are the main culprits, and may
require prolonged treatment with unusual combinations of antibiotics. Aspergillus and
'atypical mycobacteria' are also frequently found in the sputum of CF patients, but in most
cases these behave as benign 'colonisers' of the bronchiectatic airways and do not require
specific therapy. Some patients have coexistent asthma ,which is treated with inhaled
bronchodilators and corticosteroids; allergic bronchopulmonary aspergillosis also occurs
occasionally in CF .
For advanced CF lung disease ,home oxygen and NIV may be necessary to treat respiratory
failure. Ultimately ,lung transplantation can produce dramatic improvements but is limited
by donor organ availability.
Treatment of non-respiratory manifestations of CF:
There is a clear link between good nutrition and prognosis in CF. Malabsorption is treated
with oral pancreatic enzyme supplements and vitamins. The increased calorie requirements
of CF patients are met by supplemental feeding, including nasogastric or gastrostomy tube
feeding if required. Diabetes eventually appears in over 25% of patients and often requires
insulin therapy. Osteoporosis secondary to malabsorption and chronic ill health should be
sought and treated.
Somatic gene therapy
:
The discovery of the CF gene and the fact that the lethal defect is located in the respiratory
epithelium (which is accessible by inhaled therapy) presents an exciting opportunity for
gene therapy .Manufactured normal CF gene can be 'packaged' within a viral or liposome
vector and delivered to the respiratory epithelium to correct the genetic defect .Initial trials
in the nasal and bronchial epithelium have shown some effect ,and further trials of
nebulised bronchial delivery are planned. Improved gene transfer efficiency is needed
before this will become a practical clinical treatment.