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RESP > Lecture 14: Bronchiectasis and Cystic Fibrosis > Flashcards

Lecture 14: Bronchiectasis and Cystic Fibrosis Flashcards

1
Q

What is bronchiectasis?

A

Chronic irreversible dilatation of one or more of the bronchi

  • can be caused by diseases or be idiopathic
  • the deformed bronchi exhibit poor mucous clearance due to impaired cilia function: stagnant mucous pools so there is predisposition to recurrent/chronic bacterial infection
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2
Q

What causes chronchiectasis?

A

Variety of underlying causes with a common underlying mechanism of chronic inflammation

  • inflammation causes destruction of the elastic and muscular components of bronchial wall and peribronchial fibrosis
  • used be be primarily caused by pertussis (whooping cough) and TB
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3
Q

What are the radiological findings of bronchiectasis?

A

CXR- normal in early disease, non-specific abnormalities in later disease (dilated bronchi with thickened walls: tram track sign)

Gold standard: High resolution CT which demonstrates bronchial dilatation bigger than the adjacent blood vessel, bronchial wall thickening (you can see extend of damage across lung)
(signet ring sign: dilated bronchus and accompanying pulmonary artery are seen in cross section, in healthy lung bronchus is usually smaller than the artery)

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4
Q

What are the symptoms of bronchiectasis?

A

Very common

  • chronic cough
  • daily mucopurulent (mucus and pus) sputum production: vary in quantity, colour and consistency

Common

  • breathlessness on exertion
  • nasal symptoms
  • chest pain
  • fatigue
  • intermittent haemoptysis

Less common
-wheeze

(not very specific symptoms)

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5
Q

What are the clinical signs of bronchiectasis?

A
  • pulse oximetry may reveal hypoxaemia in advanced cases
  • fever is common
  • haemoptysis
  • fine crackles/wheezing/high pitched inspiratory squeaks/rhonchi
  • history of weight loss
  • clubbing of digits
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6
Q

What are the main causes of bronchiectasis?

A

Post-infective: pertussis, TB
Immune deficiency: hypogammaglobulinaemia
Mucociliary clearance defects: cystic fibrosis, primary ciliary dyskinesia, Young’s syndrome, Kartagener syndrome
Alpha-1-antitrypsin deficiency
Obstruction: forgein body/tumour/extrinsic lymph node (compression so bronchus can’t be cleared leading to inflammation)
Toxic insult: gastric aspiration/inhalation of toxic chemicals/gases
Allergic bronchopulmonary aspergillosis
Secondary immune deficiency: HIV/malignancy
RA
Idiopathic

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7
Q

What organisms do we see in chronic infections caused by bronchiectasis?

A
  • H.influenza
  • Pseudomonas aeruginosa
  • moraxella catarrhalis
  • Strep.pneumoniae
  • Stenotrophomonas maltophilia
  • Fungi: candida, aspergillus
  • Mycobacteria tuberculosis
  • Nontuberculous mycobacteria (NTM)

Antibiotic use is difficult as they become resistant

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8
Q

What do you see in bronchiectasis PFT’s?

A

Obstructive airway disease: reduced FEV1 or reduced FEV1/FVC ratio

  • elevation of RV/TLC ratio consistent with air trapping
  • diffusing capacity for CO may be reduced in severe disease
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9
Q

How do you differentiate bronchiectasis from chronic bronchitis?

A 
Chronic bronchitis
-mucous gland  hyperplasia, hypersecretion
-due to tobacco, smoke, air pollutants
-cough, sputum production
Bronchoiectasis
-airway dilatation
-scarring
-persistent/severe infections 
-cough, purulent sputum, fever
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10
Q

How do you manage bronchiectasis?

A
  • physio/airway clearance (daily)
  • sputum sampling
  • exclude immunodeficiency/treat identifiable causes
  • annual flu vaccinations
  • long term therapies
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11
Q

How do we define acute exacerbation in bronchiectasis?

A

Deterioration in 3 or more key symptoms for at least 48 hours

  • cough
  • sputum volume +/- consistency
  • sputum purulence (foul smelling)
  • breathlessness +/- exercise intolerance
  • fatigue
  • haemoptysis
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12
Q

What is the most common cause for bronchiectasis in the western world?

A

Cystic fibrosis-autosomal recessive disorder

  • Phe508del (deletion of phenylalanine at position 508 of polypeptide chain)
  • caused by mutations of gene located on long arm of chromosome 7 leading to abnormal function of CFTR (epithelial chloride channel), has a key role in maintaining lung epithelial function
  • dehydrated, viscous, site of chronic infection
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13
Q

What is the role of CFTR?

A

-transmembrane protein that transports chloride and bicarbonate and regulates ENAC
-enables Cl- to be transported out of cells into airways: helps to control movement of water
-also regulates sodium reabsorption into cells
Therefore CFTR plays critical role in hydration of mucous at surface of airway track
=defective ion transport mediated by CTFR reduces airway surface liquid hydration which leads to thick, sticky, mucous and impairs muco-ciliary clearance

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14
Q

What is the most common mutation to CFTR and its causes?

A

Phe508del CFTR protein mutation causes:

  • defective intracellular processing and trafficking
  • decreased stability (drastically reduces the quantity of CFTR protein at apical surface of epithelial cells)
  • defective channel gating
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15
Q

How do you diagnose CF?

A
  • history of CF in sibling
  • positive newborn screening test result
  • sweat test: increased sweat chloride conc
  • extended genotyping
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16
Q

What are the main CF clinical presentations?

A
  1. Meconium ileus: bowel is blocked by sticky secretions, signs of intestina obstruction after birth- bilious vomiting, abdominal distension, delay in passing meconium
  2. Intestinal malabsorption: severe deficiency of pancreatic enzymes secondary to blockage of the exocrine glands (can eventually go on to have endocrine dysfunction causing diabetes mellitus)
  3. Recurrent chest infections
  4. Newborn screening
17
Q

Can people develop CF later on in life?

A

Atypical later diagnosis of CF

  • mutation associated with residual CFTR function (gene still works but not as well)
  • recurrent sinus infection/infertility/allergic bronchopulmonary aspergillosis/recurrent pancreatitis
18
Q

What are some complications of CF?

A 
(any organs which have ducts lined by epithelial cells)
Lungs
-bronchiectasis
-pneumothorax
-ABPA
-haemoptysis
-resp failure 
Nasal/upper resp tract
-chronic sinusitis
-nasal polyposis
Pancreas
-diabetes mellitus
-pancreatic insufficiency
Gut
-oesophageal reflux
-intestinal obstruction
Liver
-chronic liver disease
-portal hypertension
Biliary tree
-gallstones
Heart
-cardiac failure
-arthritis
-osteoporosis (malabsorption)
Reproductive tract
-infertility
-congenital bilateral absence of vas deferens
19
Q

What is the CF lifestyle advice?

A
  • no smoking
  • avoid other CF patients: different resistant infections
  • avoid jacuzzis (pseudomonas colonisation here)
  • avoid friends/relatives with colds/infection
  • avoid stables/compost/rotting veg (aspergillus fumigatus inhalation)
  • annual influenza immunisation
  • vaccines
  • sodium chloride tablets in hot weather/exercise
20
Q

How do we maintain lung hygeine?

A

Saline clearance for mucous from lung

-chest physio also

21
Q

Why is nutrition so important in CF?

A

Impaired nutritional status in CF

  • pancreatic insufficiency
  • chronic malabsorption
  • chronic inflammation leading to increased energy expenditure
  • increased energy requirements of breathing
  • impaired taste, fatigue: anorexia

Nutritional therapy led to: (NG tube)

  • improved pulmonary function parameters/spirometry
  • improved respiratory muscle strength
  • gains in exercise capacity
22
Q

What are the 6 catagories of mutation in CF?

A

-no protein production
-protein made but never reaches cell membrane
-protein gets to membrane but doesn’t work as well
-protein made but only partially active
-protein expressed at gene level but substantial reduction in mRNA/protein synthesis
-protein gets to membrane but is partially unstable
=medications developed that target underlying disease mechanisms

23
Q

Why has survival improved in CF patients?

A

Understanding the importance in:

  • augmenting airway clearance 2-3x a day
  • aggressively treat infection (without overtreating)
  • correcting nutrition deficits
  • new drug treatments
24
Q

How do you cure CF?

A

Lung transplant

or heart and lung transplant

RESP (18 decks)

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