Week 3 The theory of lung sounds

Question 1

How are breath sounds classified?

Answer 1

NORMAL BREATH SOUNDS
-norm

-Bronchial breath sounds over the trachea

ABNORMAL BREATH SOUNDS

• Bronchial breath sounds (not over the trachea)
• Decreased breath sounds
• Absent breath sounds
• Adventitious breath sounds
  
  • Crackles
  • Wheezes
  • Stridor
  • Pleural rub
  • Gurgling
    * Crunching

Question 2

Describe normal breath sounds

Answer 2

Turbulent airflow generated in trachea and large airways that transmitted thorugh air in alveoli.

Muffled. High frequency sounds are filtered out.

Expiration quiter than inspiration
Heard all over the chest wall
Quieter in bases than in apices

Question 3

Bronchial breath sounds

Answer 3

Normal tracheal and large airway sounds which are heard only at the trachea in a healthy lung.

Loud hollow, high pitched.
Heard equally through inspiration and expiration

Classified as abnormal when heard in area of the lung outside the trachea .

Heard in other areas when sound is transmitted through an airless lung. But no airway obstruction

• Consolidation (airspaces filled something other than air)
• Atalectais(collapse of lung)

Question 4

Diminished breath sounds

Answer 4

Reduced sound generation (local or global)

Increased filtering of sound:

LOCALLY
Sputum plugging with distal hyperinflation
Obstruction of airway by sputum or tumour causing atalectasis
Pleural effusion or Pneumothorax
(Accumulation of fluid/air in pleural space)

GENERALLY
Obesity
Poor inspiritory effort due to pain
Emphyseyma & asthma due to a degree of airflow obstruction

Question 5

Crackles

Answer 5

Discontinous sound
Usually heard in inspiration on sudden opening of distal airspaces. Result of equalisation of pressure

or by air forced through alveoli narrowed by Oedema, inflammation or secretions.

Early inspiratory:
Usually coarse and loud
Arise in large airways
Independant of gravity 
*COPD

Mid-late inspiratory:
Hypersecretory diseases
*Bronchiectasis

Late inspiratory:
Arise in alveoli/peripheral airways
May be gravity dependant
*Pulmonary oedema
*Pulmonary fibrosis
*Elderly obese or recumbent

Question 6

Wheezes

Answer 6

Continous sound
Caused by vibration of airways due to narrowing.
Apparent more on expiration as pressure gradient changes.

Airway narrowing can be due to bronchospasm oedema or sputum

either polyphonic or monophonic

Polyphonic:
Bronchospasm
mucosal oedema
Pulmonary oedema

Monophonic
Tumor
sputum plug
Foreign body

No wheeze in someone with severe airway obstruction is not a good sign. So narrow there is no noise.

Question 7

Stridor

Answer 7

Loud high pitched sound
Heard on inspiration
from compression of extrapulmonary airways.
Opposite pressure gradient as opposed to intrapulmonary airways so narrow more on inspiration

Sign of:
upper airway obstruction
laryngeal oedema
 tracheal stenosis
croup

Question 8

Pleural rub

Answer 8

Creaking grating sound due to friction b/n pleural surfaces.

Happens when inflamed viscera and pleura rub together

Occurs at end inspiration and beginning of expiration due to maximal excursion of chest wall at this point.
Localised w chest pain in same area

cause:
Inflammation
Infection
Neoplasm

Question 9

What may gurgling indicate

Answer 9

Massive pulmonary oedema

Question 10

What is the significance of voice sounds

Answer 10

Transmitted thorugh airways and lung tissue to chest wall

Solid non aerated lung transmits speech well.
Associated with bronchial breath sounnds

Question 11

What is bronchophony?

What is whispering pectoriloquy?

Answer 11

Bronchophony-Transmission of speach

Whispering pectoriloquy- Whisper heard clearly

Question 12

What is a percussion note

Answer 12

Tapping chest wall

Evaluates density of underlying tissue.
Resonate over normal lung
Hyperesonace over Pnuemothorax

Dullness over solid lung tissue
Stoney dullness indicates pleural effusion