Bronchiectasis

What is the primary definition of Bronchiectasis?

A disorder in which the bronchi of the lungs become permanently damaged; widened and thickened.

What is the functional consequence of bronchiectasis?

This allows mucus and bacteria to build leading to frequent infections and blockages of the airways.

What key topics should be discussed regarding bronchiectasis?

The pathophysiology; clinical presentation; diagnostic evaluation (including pulmonary function testing); treatment strategies and prognosis of the patient with bronchiectasis.

What is the specific cause of bronchiectasis that must be described?

Cystic fibrosis; the most common causes of bronchiectasis.

What are the two spatial classifications for bronchiectasis?

It can be localized or diffuse.

Describe the vicious cycle of bronchiectasis pathophysiology.

Initial Insult (infection) leads to Inflammation & mucus secretion; which causes Obstruction; this results in Increased risk for recurrent infection; ultimately causing Damage to bronchial Walls leading to dilation.

What is the most common congenital cause of bronchiectasis in the US; accounting for nearly 50% of all cases?

Cystic fibrosis.

Besides cystic fibrosis; what are other congenital causes of bronchiectasis?

Abnormal lung defense mechanisms; humoral immunodeficiency; Alpha-1-antitrypsin deficiency (+ smoking); Mucociliary clearance disorders; Rheumatic disease (RA; Sjogren's); Selective immunoglobulin deficiencies (IgM; IgA; IgG).

What are the acquired causes of bronchiectasis related to lung infections?

Tuberculosis (Tb); fungal infections; lung abscess and pneumonia.

What acquired cause of bronchiectasis is the most common worldwide?

Tuberculosis (Tb).

What are examples of localized airway obstruction that can cause bronchiectasis?

Foreign body; tumor and mucoid impaction.

Which acquired immunodeficiencies can lead to bronchiectasis?

Acquired immunodeficiency from cytotoxic therapy; AIDS; lymphoma; plasma cell myeloma; leukemia.

What is the most common pulmonary symptom of bronchiectasis (98%)?

Cough.

List the common pulmonary symptoms associated with bronchiectasis and their reported prevalence.

Cough (98%); tenacious mucopurulent sputum (78%); rhinosinusitis (73%); dyspnea (62%); hemoptysis (27%); pleuritic chest pain (20%); wheezing.

What extra-pulmonary symptoms are associated with bronchiectasis?

Fatigue (43%); urinary incontinence (47%) and reduction in sense of smell.

What is the most common finding on physical exam for a patient with bronchiectasis (75%)?

Crackles.

Besides crackles; what physical exam findings are occasionally seen in bronchiectasis?

Wheezing (22%) and digital clubbing (2%).

A 45-year-old patient presents with chronic cough and tenacious sputum. On physical exam; you note crackles throughout the lung fields. What might a chest X-ray reveal?

Dilated thickened airways ("tram track sign"); linear atelectasis and irregular peripheral opacities (mucus plugging).

What radiographic sign on Chest X-ray indicates dilated thickened airways in bronchiectasis?

The “tram track sign”.

What is the gold standard imaging modality for diagnosing bronchiectasis and what specific ratio is key?

Computed tomography (CT) of the chest; showing a bronchoarterial ratio > 1 to 1.5 (internal lumen/adjacent artery).

What is the name of the radiographic sign associated with a bronchoarterial ratio > 1 to 1.5 on CT?

The “signet ring sign”.

What specific feature of the bronchi is seen on CT scan that reinforces the "tram track appearance" seen on CXR?

Lack of tapering of bronchi.

What specific measurement regarding bronchial visibility near the pleura suggests bronchiectasis on CT?

Airway visibility within 1 cm of costal pleural surface or touching mediastinal pleura.

What type of impairment is most often observed when performing Pulmonary Function Testing (PFT) for bronchiectasis?

Obstructive impairments.

What are the typical PFT results consistent with obstructive impairment in bronchiectasis?

Low FEV1; low FEV1/FVC and reduced/normal FVC.

What basic labs and initial specimen analysis should be ordered when diagnosing bronchiectasis?

CBC and sputum smear (for bacteria; mycobacteria; fungi).

What specific patient-specific labs are necessary to investigate underlying causes of bronchiectasis?

Immunoglobulin quantitation; cystic fibrosis testing; Aspergillus immunoglobulin; Alpha-1-antitrypsin level and Rheumatoid factor.

What is the most common pathogen identified in sputum cultures of bronchiectasis patients?

Haemophilus Influenzae.

Which microbial pathogen cultured from bronchiectasis sputum is associated with an accelerated course of the disease?

Pseudomonas aeruginosa.

List other common pathogens found in bronchiectasis sputum cultures besides H. influenzae and P. aeruginosa.

Streptococcus pneumoniae; Staphylococcus aureus and nontuberculous mycobacterium.

What are the four primary treatment strategies for bronchiectasis?

Antibiotics; daily chest physiotherapy with postural drainage & chest percussion; inhaled bronchodilators and surgical resection.

What criteria must be met to consider surgical resection for bronchiectasis?

It is used only in rare patients with localized disease and adequate pulmonary function when conservative treatment fails.

How should antibiotic treatment for acute exacerbations of bronchiectasis be guided?

Guided by sputum smear; culture & prior cultures.

If a specific pathogen cannot be isolated during an acute bronchiectasis exacerbation; what is the duration and route for empiric antibiotics?

Empiric oral antibiotics for 10-14 days.

List examples of empiric oral antibiotics used for acute bronchiectasis exacerbations.

Amoxicillin or Augmentin (Amoxicillin + clavulanic acid) 500mg Q8h; Ampicillin 250-500mg QID; Doxycycline 100mg BID; Bactrim (trimethoprim-sulfamethoxazole) 160/800mg q12h and Ciprofloxacin 500-750mg BID.

What chronic measure is used for stable outpatients with copious purulent sputum for prevention/suppression of bronchiectasis exacerbations?

Prolonged macrolide therapy.

Provide an example dosing regimen for prolonged macrolide therapy (Azithromycin) used for chronic suppression in bronchiectasis.

Azithromycin 500mg 3x/week x 6 months or 250mg QD x 12 months.

What are the manual chest physical therapy (CPT) techniques used to clear secretions?

Postural drainage and percussion & vibration.

What mechanical and handheld devices are used for airway clearance therapy?

Mechanical CPT by inflatable vest (expensive) and hand held flutter devices (which may be as effective as CPT).

What are the major complications of bronchiectasis?

Hemoptysis (sometimes massive); cor pulmonale; amyloidosis and secondary visceral abscess at distal sites.

What interventions may be required for massive hemoptysis resulting from bronchiectasis?

Bronchoscopy; embolization or surgical resection.

What factors influence the prognosis of bronchiectasis?

It depends on the underlying cause.

What is the overall annual mortality rate for bronchiectasis?

16-20% per year.

Patients with bronchiectasis are at increased risk for which associated diseases?

Pulmonary vascular disease; cardiovascular disease and lung cancer.

Define Cystic Fibrosis (CF) based on inheritance and the glands affected.

Autosomal Recessive inherited disease of mucus and sweat glands.

What protein mutation is central to the pathophysiology of Cystic Fibrosis?

Mutations in the Cystic Fibrosis Conductase Regulator (CFTR) protein.

What is the function of the CFTR protein and how does its dysfunction affect the body?

It is a transmembrane channel that transports chloride; leading to thick viscous secretions in the lungs; pancreas; liver; intestine & reproductive tract.

Why does the thick mucus associated with cystic fibrosis lead to persistent infections?

This mucus is an ideal environment for bacterial colonization.

What are the three clinical scenarios that meet the first diagnostic criterion for Cystic Fibrosis?

Clinical symptoms consistent with CF in at least one organ system; OR positive newborn screen; OR have a sibling with CF.

What must be demonstrated to fulfill the second diagnostic criterion for Cystic Fibrosis?

Evidence of cystic fibrosis transmembrane conductance dysfunction.

What is the required threshold for sweat chloride testing to confirm cystic fibrosis (the first test to order)?

Elevated sweat chloride 60 mmol/L $\ge$.

Besides elevated sweat chloride; what other evidence confirms CFTR dysfunction for diagnosis?

Presence of two disease causing mutations in the CFTR gene (one from each parental allele) or abnormal NPD testing (nasal potential difference).

If a newborn screen for CF is negative but clinical suspicion is high; what action is recommended?

Pursue further testing even if newborn screen negative; due to an up to 5% false negative rate.

What category of medications targets the fundamental defect in cystic fibrosis?

CFTR modulators.

List the inhaled airway clearance agents used in the chronic treatment of cystic fibrosis.

DNase and Hypertonic Saline.

What types of medications are used chronically in CF management besides CFTR modulators and airway clearance agents?

Bronchodilators; anti-inflammatories and short/long-term antibiotics.

Besides medications; what other interventions are crucial for chronic CF management?

Airway clearance therapies; chest physiotherapy; exercise and infection prevention (including vaccinations).

In managing acute CF exacerbations; when are glucocorticoids indicated?

In patients whose exacerbations have asthmatic qualities (tightness; wheezing; response to b-adrenergic agonists).

What respiratory support measures might be used during severe acute CF exacerbations?

Supplemental O2; noninvasive or invasive ventilation and Extracorporeal membrane oxygenation support (ECMO).

How should antibiotics be chosen during acute CF exacerbations?

Based on sputum cultures & susceptibility testing.

A 60-year-old male with a history of recurrent pneumonia presents with chronic wet cough and copious mucopurulent sputum. His chest X-ray shows thickened; dilated bronchi; described as a "tram track sign." Which diagnostic finding would confirm the presence of bronchiectasis on chest CT?

A bronchoarterial ratio > 1 to 1.5; also known as the “signet ring sign”.

A 19-year-old patient with known bronchiectasis is undergoing an etiological workup. His workup reveals an elevated sweat chloride concentration of 75 mmol/L. What is the most likely underlying congenital cause of his bronchiectasis?

Cystic fibrosis.

A 55-year-old non-CF bronchiectasis patient presents with an acute exacerbation. Sputum culture is pending; but empiric therapy is started. Which combination of drug class and duration is appropriate for empiric oral treatment?

Oral antibiotics for 10-14 days; such as Amoxicillin/Augmentin or Ciprofloxacin.

A bronchiectasis patient has a sputum culture that reveals Pseudomonas aeruginosa. What clinical course does this organism suggest?

An accelerated course of the disease.