Bronchiectasis Revision Notes

DEFINITION OF BRONCHIECTASIS

Bronchiectais refers to the end-stage of variety of pathologic processes characterized by abnormal, irreversibly dilated thick-walled bronchi due to destruction of elastic and muscular components of bronchial wall.

MORPHOLOGICAL CLASSIFICATION OF BRONCHIECTASIS

Mnemonic: CVS

bronchiectasis types

1. Cylindircal (Fusiform):

  • involves airways from 6th-10th generation
  • bronchi have uniform calibre, do not taper and have parallel walls
  • commonest form

2. Varciose:

  • resembles varicose vein
  • beaded appearance where dilated bronchi have interspersed sites of narrowing
  • relatively uncommon

3. Saccular (Cystic):

  • occurs in proximal bronchi
  • dilation ends in large cysts, saccules or grape-like clusters
  • most severe form

ETIOLOGY OF BRONCHIECTASIS

a. Structural lung conditions:

  • Williams-Campbell syndrome (deficiency or absence of cartilage, mostly from the third division of the bronchi down)
  • Mounier-Kuhn syndrome (tracheobronchomegaly)
  • Ehler’s Danlos syndrome

b. Toxic damage to airways:

  • Inhalational injury
  • Aspiration secondary to neuromuscular disease
  • GERD

c. Obstruction of single bronchus:

  • Foreign body
  • Tumor
  • Lymph nodes

d. Obstructive airway disease:

  • Asthma
  • COPD
  • Alpha-1-antitrypsin deficiency

e. Defects of mucociliary clearance:

  • Ciliary dyskinesia: Primary (e.g. Kartagener’s syndrome), Secondary (P.aeruginosa, H.influenzae, cigarette smoke, aspiration of gastric contents)
  • Channelopathies: CFTR (inhibitor of eNAC) dysfunction (Cystic fibrosis), eNAC dysfunction

f. Allergic Bronchopulmonary Aspergillosis (ABPA)

g. Immunodeficiency:

  • Common Variable Immunodeficiency (CVID)
  • X-linked Agammaglobulinemia (XLA)
  • Chronic granulomatous disease (CGD)
  • Secondary: Hematologic malignancy, GVHD

h. Infections:

  • Childhood infections: TB, pneumonia, measles, whooping cough
  • Nontuberculous mycobacteria

i. Traction:

  • Post-tuberculous fibrosis
  • Post-radiation fibrosis
  • Fibrosis (sarcoidosis)
  • Inflammatory bowel disease

j. Connective tissue diseases

k. Yellow nail syndrome (bronchiectasis, lymphoedema and a characteristic appearance of the nails)

l. Idiopathic

PATHOGENESIS OF BRONCHIECTASIS

bronchiectasis pathogenesis

cystic fibrosis pathogenesis

PATHOLOGY OF BRONCHIECTASIS

  1. Characterisitc feature: multiple bronchiectatic cavities
  2. Left lung is involved more than right lung
  3. Lower lobes are involved more than upper lobes due to more efficient drainage of upper lobes by gravity
  4. Common sites of involvement: lower lobes, lingula and middle lobe
  5. Smaller bronchi with less supportive cartilage are predominantly involved

PATHOPHYSIOLOGY AND CLINICAL FEATURES OF BRONCHIECTASIS

The clinical manifestations result due to pathophysiologic mechanisms caused by following anatomic alterations:

  1. Incomplete obstruction: Hyperinflation of the distal alveoli as a result of expiratory check-valve mechanism
  2. Complete obstruction: Atelectasis, consolidation and fibrosis

A. Cough, Sputum production, Hemoptysis and Recurrent Infection:

  • Chronic cough with production of large quantities of foul-smelling sputum (due to anaerobic infection) is a hallmark
  • Productive cough: due to stimulation of subepithelial mechanoreceptors in tracheobronchial tree by stagnant secretion, which produces vagal reflex that triggers cough
  • 24 hour collection of sputum: is usually voluminous and tends to settle in 3 different layers – mucoid layer on top, mucopurulent layer in middle and purulent layer at bottom
  • Sputum production varies with posture: and is maximum within 2 hours of waking up (stagnation of sputum while asleep)
  • Hemoptysis: due to necrosis of bronchial wall and erosion of bronchial blood vessels
  • Secondary bacterial infection: frequent due to excessive bronchial secretion – H.influenzae, Streptococcus, P.aeruginosa, various anaerobic organisms

Bronchiectasis sicca (Dry bronchitis): repeated episodes of hemoptysis without sputum production; occurs in upper lobe bronchiectasis of post-tubercular variety

Middle lobe bronchiectasis/Middle lobe or Brock’s syndrome: post-obstructive bronchiecatasis due to obstruction of middle lobe by tubercular lymph nodes

B. Vital signs:

1. Tachypnea:

  • Stimulation of peripheral chemoreceptors (V/Q mismatch and hypoxemia)
  • Decreased lung compliance and increased ventilatory rate relationship
  • Anxiety

2. Tachycardia and Raised Blood pressure:

  • Stimulation of medullary vasomotor center (V/Q mismatch and hypoxemia)

3. Fever: Inflammatory response in cases of infection

C. General examination:

Use of accessory muscles, Pursed lip, Barrel chest:

  • Increased airway resistance and increased work of breathing

Cyanosis:

  • Hypoxemia

Digital clubbing (2-3% cases):

  • Megakaryocytes bypass lung mechanism and lodge in peripheries and release PDGF and VEGF resulting in vasodilation and fibroblast deposition

Peripheral edema and venous distension:

  • Corpulmonale

4. Chest findings:

  • When bronchiectasis pathology is primarily obstructive:
    • Decreased tactile and vocal fremitus; Hyperresonant percussion note
      • Decreased lung density
    • Diminished breath sounds
      • More air in alveoli – hence, more muffling effect of alveolar air
    • Prolonged expiration
    • Wheezing
    • Crackles
  • When bronchiectasis is primarily restrictive (atelectasis, fibrosis, consolidation):
    • Increased tactile and vocal fremitus; Dull percussion note
      • Increased lung density
    • Bronchial breath sounds
      • No air in alveoli – hence, muffling effect of alveolar air lost
    • Crackles
    • Whispering pectoriloquy
      • Increased lung density

INVESTIGATIONS FOR BRONCHIECTASIS

A. Pulmonary Function Test (PFT) findings:

1. Primarily obstructive pattern:

FVCFEVTFEV1/FVC ratioFEF25%-75%
FEF50%FEF200-1200PEFRMVV
VTIRVERVRV
N or ↑N or ↓N or ↓
VCICFRCTLCRV/TLC ratio
N or ↓N or ↑N or ↑

2. Primarily restrictive pattern:

bronchiectasis pft

B. ABG findings:

1. Mild to moderate stages: Acute alveolar ventilation with hypoxemia (Respiratory alkalosis)

  • Increased pH, decreased PaCO2, decreased PaO2, decreased HCO3

2. Severe stages: Chronic ventilatory failure with hypoxemia (Compensated respiratory acidosis)

  • Normal pH, Increased PaCO2, Increased HCO3 (significantly), Decreased PaO2

C. Oxygen indices:

1. Qs/Qt (Shunt equation – percentage of blood flow not exposed to inhaled gas): Increased

Qs/Qt = (CcO2 – CaO2)/(CcO2 -CvO2) * 100
CcO2 = Oxygen content of pulmonary capillary
CaO2 = Oxygen content of artery
CvO2 = Oxygen content of vein
Normal <10%

2. DO2 (Total oxygen delivery): Decreased

DO2 = Cardiac output x (CaO2 x 10)
Normal ~ 1000 mlO2/min

3. C(a-v)O2 (Arterial venous oxygen content difference): Normal

C(a-v)O2 = CaO2 – CvO2
Normal ~ 5 vol%

4. VO2 (Oxygen consumption): Normal

VO2 = Cardiac output X C(a-v)O2 X 10
Normal ~ 250 mlO2/min

5. O2ER (Oxygen extraction ration): Increased

O2ER = (CaO2 – CvO2)/CaO2
Normal ~ 0.25

6. SvO2 (Mixed venous oxygen saturation): Decreased

Normal 65-75%

D. Abnormal Lab tests and results:

1. Complete blood count:

  • Increased hematocrit and hemoglobin (hemoglobin may be low due to anemia of chronic inflammation)
  • Increased WBC in acute infection

2. Sputum culture results:

  • S.pneumoniae
  • H.influnezae
  • P.aeruginosa
  • Anaerobic organisms

E. ECG:

  • Normal (usually)
  • Features of Right Ventricular Hypertrophy (RVH) and Cor pulmonale

F. Chest Radiographs:

With primarily obstructive disease:

  1. Emphysematous changes with tubular heart
  2. Enlarged heart (if heart failure present)
  3. Tram-tracks (cylindrical), Honey-comb (cystic), signet-ring deformity
  4. Areas of consolidation and/or atelectasis may be seen

bronchiectasis radiograph

bronchiectasis imaging

With primarily restrictive disease:

  • Atelectasis and consolidation
  • Infiltrates (suggesting pneumonia)
  • Increased opacity

Bronchogram has been replaced by HRCT.

Specific features:

  • ABPA: upper zone central bronchiectasis
  • Cystic fibrosis: upper zone bronchiectasis
  • Nontuberculous mycobacteria and MAC: middle lobe irregular branching and tree-in-bud appearance

G. Bronchoscopy:

  • Doesn’t establish diagnosis
  • For identifying source of secretions
  • For identifying the site of bleeding in hemoptysis
  • For therapeutic and diagnostic evacutation of sputum
Bronchoscopy findings include the following:
  • Dilatation of airways and purulent secretions
  • Thickened bronchial walls with necrosis of bronchial mucosa
  • Peribronchial scarring

H. Further investigations according to suspected cause:

AetiologySuggestive signsAdditional investigationsExpected abnormalities
Cystic fibrosisAge under 40, malabsorption, poor growth, infertility in males, faecal masses on abdominal x-ray, diabetesSweat testPositive sweat test: chloride concentration >60 mEq/l
Genetic testing2 CFTR mutations
NPDAbnormal NPD
Congenital disordersPrimary ciliary dyskinesia: sinusitis, otitis media, hearing loss, poor sense of smell, middle lobe predominanceNasal epithelial brushing or biopsyAbnormal ciliary beat pattern and frequency of ciliogenesis in culture
Nasal NO measurement (>5 years of age)Nasal NO <150 ppb
Saccharin test (no clinical value anymore)Increased time (>60 min) before tasting saccharin
Marfan’s syndrome: myopia, arachnodactylia, tall stature, thoracic deformations, glaucoma, abnormal joint flexibility, heart murmurSearch for major and minor indicators of the disorderDiagnosis based on family history and a combination of major and minor indicators of the disorder, rare in the general population but occurring in one individual Genetic testing
α1-Antitrypsin deficiencyα1-Antitrypsin deficiencyLevels below 150 mg/dl
Anatomical deformations: visible on clinical examinationThoracic imagingScoliosis or pectus excavatum
IBDDiarrhoea, abdominal pain, haematochezia, weight loss, arthritis, pyoderma gangrenosum, primary sclerosing cholangitisColonoscopy with biopsy of pathological lesionsBiopsy inflammation suggestive of IBD
Gastrointestinal advice
Coeliac diseaseMalabsorption, chronic diarrhoea, failure to thrive in children, fatigue, mouth ulcers, anaemia, weight loss, dermatitis herpetiformistTG antibodies and IgAPositive tTG antibodies test without IgA deficiency
Endoscopic duodenal or jenunal biopsiesLymphocytic infiltration, villous atrophy
Post infectiousHistory of multiple pulmonary infections, tuberculosis or cough suppressionHistory or radiological evidence of previous infectionRadiological evidence of previous infection, history of cough suppression
Sputum with smear and culture for acid-fast bacilliPositive for Mycobacterium aviumcomplex or other mycobacteria
Immunological disordersPrimary: recurrent infections, developmental delay in children, particular organ problemsIgG and subclasses, IgA, IgMDecreased values, depending on age of patient. Adult: IgG<7.51 g/l; IgA<0.82 g/l; IgM<0.46 g/l
Full blood countLymphocyte or granulocyte deficit
Neutrophil antibody and function test, challenge with common humoral bacterial antigensResult suggestive of antibody presence or impaired function
Secondary: lung transplant patients, patients under immunosuppressive therapy, HIVIgG and subclasses, IgA, IgMDecreased values, depending on age of patient
HIV testingPositive HIV serology
ABPAAsthma, wheezing, coughing up brownish mucoid plugs or blood, upper lobe predominanceTotal IgE, sputum sampleRaised total IgE>1000 ng/ml, presence in sputum
Specific serum IgE and IgG toAspergillus fumigatusRaised Aspergillus IgE and/or IgG
Aspergillus fumigatus skin prick testPositive skin prick test
Rheumatic disorders (RA, SLE, Sjögren, ankylosing spondylitis, relapsing polychondritis)RA: rheumatoid nodule, arthritis, synovitis, specific skeletal deformities, rheumatoid nodule, other skin symptoms, etcAutoimmune screening: rheumatoid factor, ANCAs, ANAs and anti-citrullinated peptide antibodiesDiagnosis depending on clinical examination combined with autoimmune screening results (positivity of rheumatoid factor, anti-citrullinated peptide antibodies, ANCAs, ANAs and/or ANA subtypes)
SLE: malar rash, ulcers, neuropsychiatric symptoms, etcRheumatological advice
COPDDyspnoea, Smoking history, Recurrent infectionsSpirometry, bronchodilatation testObstructive lung function
Traction, obstruction, inhalationSarcoïdosis: fatigue, erythema nodosum, lupus pernio, arthralgia, uveitis, Bell’s palsy, etcChest CT scanHilar lymphadenopathy, reticulonodular infiltrates, pulmonary infiltrates, fibrocystic or bullous changes, non-caseating granulomas, upper lobe predominance
History of radiation therapyBiopsy
History of inhalation/aspiration traumaBronchoscopy if imaging showing foreign body
YNS, Young’s syndrome, amyloidosis, endometriosisYNS: yellow dystrophic nails, lymphoedema, sinusitis, pleural effusionExclusion diagnosis based on imaging and clinical findings
Young’s syndrome: history of mercury contact, rhinosinusitis, infertilityUrological advice
Endometriosis: pelvic pain, infertility, cyclic haemoptysis/painGynaecological evaluation
IdiopathicLower lobe predominance, combined chronic rhinitis/sinusitisAll of the above excludedExclusion diagnosis
  • ABPA, allergic brochopulmonary aspergillosis; ANA, anti-nuclear antibodies; ANCA, anti-neutrophil cytoplasmic antibodies; CFTR, cystic fibrosis transmembrane conductance regulator; COPD, chronic obstructive pulmonary disease; IBD, inflammatory bowel disease; NPD, nasal potential difference; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus; tTG antibodies, tissue transglutaminase antibodies; YNS, yellow nail syndrome.

BRONCHIECTASIS SEVERITY INDEX

Mnemonic: ABCDEFGH

  • Age
  • BMI
  • Colonization status
  • Dyspnea index (mmRC)
  • Exacerbations in last 12 months
  • FEV1% predicted
  • Grading radiologically
  • Hospital admissions in past 2 years

Severity criteria

0 points

1 point

2 points

3 points

4 points

5 points

6 points

Age

<50

50-69

70-79

80+

BMI kg/m2

>18.5

<18.5

FEV1 % predicted

>80%

50-80%

30-49%

<30%

Hospital admissions in the past 2 years

No

Yes

Exacerbation frequency in last 12 months

0-2

3 or more

MRC dyspnoea score

1-3

4

5

Colonisation status

Not colonised

Chronic colonisation

P. aeruginosa  colonisation

Radiological severity

<3 lobes involved

3 or more lobes or cystic changes

Interpretation:

0-4: Mild bronchiectasis

  • 1 year outcome: <2.8% mortality rate; <3.4% hospitalization rate
  • 4 year outcome: <5.3% mortality rate; <9.2% hospitalization rate

5-8: Moderate bronchiectasis

  • 1 year outcome: 0.8-4.8% mortality rate; 1-7.2% hospitalization rate
  • 4 year outcome: 4-11.3% mortality rate; 9.9-19.4% hospitalization rate

9+: Severe bronchiectasis

  • 1 year outcome: 7.6-10.5% mortality rate; 52.6% hospitalization rate
  • 4 year outcome: 9.9-29.2% mortality rate; 41.2-80.4% hospitalization rate

COMMON DIFFERENTIAL DIAGNOSES OF BRONCHIECTASIS

bronchiectasis differential

MANAGEMENT OF BRONCHIECTASIS

bronchiectasis treatment

A) Treat underlying conditions

B) Recognize and treat acute exacerbation:

Recognize an acute exacerbation with 4 out of 9 criteria

  • Change in sputum production
  • Increased dyspnea
  • Increased cough
  • Fever
  • Increased wheezing
  • Malaise, fatigue, lethargy
  • Reduced pulmonary function
  • Radiographic changes
  • Changes in chest sounds

Antibiotic choice –

bronchiectasis antibiotics

Source: http://www.dbh.nhs.uk/Library/Pharmacy_Medicines_Management/Formulary/Formulary_S5/COPD%20Flowchart.pdf

bronchiectasis exacerbation oral antibioticsbronchiectasis exacerbation iv antibiotics

Source: Antibiotic treatment strategies in adults with bronchiectasis – C.S. Haworth

C) Maintenance treatment:

1. Pulmonary rehabilitation, improved nutrition and vaccination:

pulmonary rehabilitation

Get a brief idea on breathing techniques.

Airway clearance therapy: postural drainage, percussion, vibration, and the use of oscillatory devices for 15 to 30 minutes, 2 or 3 times daily.

Vaccination: Influenza vaccine and 23 valent pneumococcal vaccone

2. Inhaled bronchodilator:

  • Appropriate for patients with co-morbid COPD or Asthma
  • May improve tolerability of hyperosmolar agents
  • Options:
    • Salbutamol inhaled: 200 micrograms (2 puffs) every 4-6 hours when required; 2.5 mg nebulised every 6-8 hours when required
    • Arformoterol inhaled: 15 micrograms nebulised every 12 hours when required
    • Salbutamol/ipratropium inhaled: 200/40 micrograms (2 puffs) every 6 hours when required
    • Ipratropium inhaled: 40 micrograms (2 puffs) every 6 hours when required
    • Tiotropium inhaled: 18 micrograms (1 capsule) inhaled once daily when required

3. Inhaled hyperosmolar agent:

  • Use bronchodilator prior to administration
  • Shown to reduce inflammatory mediators, improve sputum bacteriology, and improve quality of life
  • Options: hypertonic saline or mannitol

4. Long-term oral macrolide:

  • Benefits: small improvement in FEV1, decreased sputum volume, and decreased exacerbation rate
  • Action: Immunomodulatory
  • Option: Azithromycin 250 mg orally once daily, or 500 mg orally three times weekly
  • Disadvantages:
    • Resistance development: Presence of mycobacteria in the sputum necessitates prompt discontinuation of macrolide monotherapy to minimise the risk of resistance developing.
    • Cardiovascular risk: QTc prolongation

5. Inhaled antibiotic:

  • Indication: high risk for chronic Pseudomonas infection (repeated exacerbations, recent history of antibiotic use, cystic fibrosis)
  • Options:
    • Tobramycin inhaled: 300 mg nebulised every 12 hours; give in cycles of 28 days on and then 28 days off
    • Colistimethate sodium: dose depends on local formulation
    • Gentamicin: 80 mg nebulised every 12 hours (no cycling)
  • Disadvantages:
    • Adverse events: some patients also suffered from cough, wheezing, and fatigue in response to the treatment
    • Resistance development

6. Inhaled steroids:

Insufficient evidence exists to recommend use of inhaled steroids with stable bronchiectasis.

A therapeutic trial of inhaled steroids may be justified in adults with difficult-to-control symptoms.

Decrease sputum and tend to improve lung function

  • Fluticasone propionate: 110–220 μg inhaled BID
  • Potential synergistic effect of long-acting β2-agonists with inhaled corticosteroids, allowing for lower steroid dose: Budesonide 160 μg/Formoterol 4.5 μg 2 puffs inhaled BID

7. Mucolytics:

  • Avoid recombinant DNAse B in non-CF Bronchiectasis
  • Options (use with antibiotics): Bromhexine 30 mg TDS, Erdosteine (mucolytic with antibacterial, antioxidant, anti-inflammatory properties)

Use of BRMs: In patients with recurrent episodes of pneumonia and bronchitis, BRMs be avoided until more trials have been carried out.

D) Surgery:

Indications:

  • Recurrent infections
  • Hemoptysis
  • Focal disease

Options:

  • Complete resection of bronchiectatic areas of lungs
  • Lung transplantation

E) Supplemental oxygen and NIV:

  • For severe ventilatory failure

Disclaimer: This is only for learning purpose and shouldn’t be used as a reference for the management.

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