Lung B36. Chronic bronchitis, Brochiectasis, cystic fibrosis.

Question 1

Clinical definition of chronic bronchitis

Answer 1

Persistent cough for at least 3 months over 2 consecutive years.

Question 2

What are the 3 types of chronic bronchitis?

Answer 2

Simple CB, Productive cough with mucinous sputum, but no significant airway obstruction. This is the early stage of chronic bronchitis

Chronic asthmatic bronchitis: hypersensitive airways develop in response to the chronic bronchitis with broncho-spasm and wheezing, chronically for 3 months and 2 years.

Chronic bronchitis with outflow obstruction and emphysema, seen mostly in a subset of heavy smokers.

Question 3

What is the origin/pathogenesis of chronic bronchitis?

What are the characteristic histology changes?

Answer 3

Chronic exposure to airway irritants –> chronic inflammation. Secondary infections may prolong and maintain the inflammation, but they are not the primary driver of the disease.

T cells, lymphocytes, macrophages, and neutrophils infiltrate (with no eosinophils) infiltrate.

Mucousal hyperemia and edema

Hypersecretion of mucous and hyperplasia of the subepithelial mucous gland layer. Increasing the Reid index to >50% (40% is normal).

Squamous cell metaplasia of respiratory epithelium is also evident in response to the irritants. Goblet cell metaplasia of the epithelium may also occur, contributing to the mucous plugs.

Mucous plugging of the small airways is termed Bronchiolitis obliterans.

Chronic bronchitis usually presents with concommittant centriacinar emphysema.

Question 4

What are the symptoms of chronic bronchitis?

Answer 4

Persistent cough with extremely copious sputum.

The mucous plugs and frequent concommitant emphysema causes COPD.

Hypoxia, hypercapnia, cyanosis (blue bloaters)

frequent/increased risk for infections due to

Increased Total lung capacity, Increased residual volume, increased functional residual capacity.

Decreased FEV1 that is not reversible. Decreased FEV, decreased Vital capacity

Pulmonary hypertension, cor pulmonale chronicum.

Question 5

What are the causes of Brochiectasis?

Answer 5

It is caused by necrotising inflammations that degrade the bronchial wall.

1. Obstructions
   
   • Mucous plugs: Chronic bronchitis, Atopic asthma
   • Tumor mass
   • Foreign body
   • Tuberculosis/Granuloma
2. Cystic Fibrosis
3. Immune deficeincies
4. ABPA, Allergic BronchoPulmonary Aspergillosis
   
   • Occurs in patients with Cystic Fibrosis or Asthma
5. Necrotizing pneumonias
   
   • Klebsiella
   • Staph Aureus
   • Haemophilus influenzae
   • Pseudomonas aeruginosa
   • Usually they are mixed infections

Question 6

What are the symptoms of bronchiectasia?

Answer 6

Fever and cough with purulent very smelly sputum, potentially hemoptysis

dyspnea, with difficulty emptying airways that is non-reversible due to turbulence in the dilated airways and inneffective air expulsion, also air trapping by the sputum/mucus.

Hypoxia, Hypercapnia,

Pulmonary hypertension, cor pulmonale chronicum

Secondary AA type amyloidosis –> Renal, spleen, liver problems.

Nail clubbing is also possible.

Usually affects the lower lobes the most.

Question 7

What is the cause of Cystic Fibrosis?

Answer 7

A genetic autosomal recessive mutation of the CFTR Chloride ion channel.

Mutations range from mild decrease in activity to total knockout.

Question 8

What are the major organs affected by cystic fibrosis and their pathologies?

Answer 8

Lung, Pancreas, GI tract, Liver, and Male genital system

Lung: is the most significant pathological site.

Decreased Cl secretion, decreased water secreted. Viscous mucinous lung secretions causing:

• obstruction,
• cysts,
• chronic infections,
• bronchiectasia,
• interstitial fibrosis,
• cor pulmonale chronicum,
• systemic AA amyloidosis.

Pseudomonas aeruginosa, Haemophilus influenza, Staph aureus are the most common infections.

Pancreas: Is the most common site, 85-90% of all of patients have symptoms

• reduces CL secretion, viscous pancreatic secretions
• blocked ducts, chronic pancreatitis: cysts, atrophy, fibrosis,
• pancreatic insufficiency
• lipid malabsorption
• protein malabsorption

GI: Presents problems mostly in newborns small intestine, Viscous plug obstructs the intestine completely causing meconium illeus.

Liver: Bile canaliculi obstruction

• Causing obstructive jaundice.
• chronically, Steatosis and cirrhosis.

Male genitals:

• 95% will have congeintial absense of vas deference, bilaterally,
• Even if it is present, sprematogenesis fails and they are infertile.

Question 9

Diagnosis of CF

Answer 9

1. Salty sweat
2. Meconium illeus in infants
3. Family history
4. Genotyping
5. protein and lipid malabsorption
6. diarrhea/steatorrhea
7. Persistent lung infections
8. Obstructive/cystic pulmonary disease
9. Obstructive jaundice
10. Male infertility