MECHANISM OF NORMAL BREATH SOUNDS

Normal breath sounds originate from the larynx. When the sound leaves the larynx it travels down the trachea and then divides when the airway divides. Some sound must be transmitted through the lung parenchyma but most travels down the airway. Eventually the sound travels along airways of different lengths and therefore becomes out of phase. Next it arrives in the respiratory bronchioles and alveoli and then gets transmitted through the chest wall to your stethoscope. The fat layer filters out much of the high frequency sound (above 4 kHz). The resulting sounds are much softer (because the sound has effectively been diluted throughout the whole of the lungs). There is no gap between inspiration and expiration (because all of the sound has become out of phase and therefore filled in the gap. Finally, the first third of expiration is now the only part that is audible because the latter two-thirds are much quieter.

REFERENCE : CHAMBERLAIN'S symptoms and signs of clinical medicine, 13th edition

 ILO CLASSIFICATION TO DESCRIBE PNEUMOCONIOTIC OPACITIES

ILO TERM                  OPACITY WIDTH                              OPACITY TYPE

P                                   < 1.5mm                                               Small rounded

Q                                  1.5 - 3 mm                                            Small rounded

R                                   > 3 - 10 mm                                         Small rounded

S                                   < 1.5mm                                               Linear/ Irregular

T                                   1.5 - 3 mm                                            Linear/ Irregular

U                                   > 3 - 10 mm                                         Linear/ Irregular

A                                   > 10 - 50 mm                                        Large

B                                   > 50 mm - RUZ                                    Large

C                                    > RUZ                                                  Large

Cardinal symptoms

 1. COUGH

Aggravating factors:

Pollution, Pollen, Posture

Drugs, Diurnal, Dry air

Food

Cold weather, Common cold

Exercise

Relieving Factors:

Using cough suppressants or expectorants

Drinking warm fluids 

Humidified air or steam inhalation

Avoiding triggers 

Rest

2. SPUTUM

Aggravating Factors:

Respiratory infections (e.g., bronchitis, pneumonia)

Exposure to cold air or smoke

Allergic reactions

COPD, asthma

Physical activity 

Relieving Factors:

Hydration 

Expectorants 

steam inhalation

Deep breathing exercises

3. HEMOPTYSIS 

Aggravating Factors:

Trauma or injury to the respiratory tract

Relieving Factors:

Treating the underlying condition 

Cough suppressants 

Oxygen therapy 

Positioning the person to reduce coughing or to prevent aspiration

4. CHEST PAIN

Aggravating Factors:

Deep breathing, coughing, sneezing (if pleuritic)

Physical exertion (if cardiac in nature)

Stress or anxiety

Movement or pressure on the chest area

acid reflux

Relieving Factors:

Rest 

Pain medication

Positioning (e.g., lying on one side for pleuritic pain)

Relaxation or stress-reduction techniques

Oxygen therapy

5. BREATHLESSNESS

Aggravating Factors:

Physical exertion or exercise

Exposure to cold air or allergens

Respiratory infections

Anxiety or panic attacks

Relieving Factors:

Rest or reducing physical activity

Oxygen therapy 

Bronchodilators 

Calm breathing techniques 

Elevating the head or upper body in severe cases

6. WHEEZE

Aggravating Factors:

Exposure to allergens or irritants (e.g., smoke, dust, pollen)

Respiratory infections 

Exercise or physical activity 

Cold air or sudden weather changes

Anxiety or panic attacks

Relieving Factors:

Bronchodilators 

Avoidance of triggers

Breathing exercises 

Inhaling steam

Rest and calm environment

Honeycombing in HRCT

Honeycombing is defined by the presence of small air containing cystic spaces generally lined by bronchiolar epithelium and having thick walls composed of dense fibrous tissue.

Indicates presence of end stage lung disease 

Characteristics of honeycomb cysts:

Thick walled

Air filled(black)

3-10mm in diameter 

Immediately subpleural in location 

Occur in clusters or layers and share walls

Non branching

Associated with other findings of fibrosis (traction bronchiectasis, irregular reticulation, volume loss and lung distortion)

Referrence- HRCT OF LUNG BY WEBB pg no-82(5th edition)

Role of aminophylline in asthma

 Aminophylline - It is a phosphodiesterase inhibitor used as an adjunct bronchodilator treatment.

Aminophylline predominantly inhibits PDE3 in airway smooth muscles which increases intracellular cyclic AMP leading to bronchodilator effect.

Also has anti-inflammatory properties.

Therapeutic range of 10 -20 mg/l.

Due to narrow therapeutic index and adverse effect profile, along with availability of more effective alternatives, it is now infrequently used in patients with asthma.

Acute exacerbation of IPF

 A previous or concurrent diagnosis of IPF

with 

1.acute worsening or development of dyspnea of typically less than 1 month(clinically)

2.new bilateral ground glass opacity or consolidation superimposed on a background consistent with UIP pattern 

3.Deterioration not fully explained by cardiac failure or fluid overload or infection.

Acute exacerbation of COPD

 AE of COPD is characterized by worsening of respiratory symptoms (cough, wheeze and dyspnea) more than usual day to day variation and requires changes in the medications.

Pathophysiology of breath sounds

 Normal breath sounds originate from the larynx .When the sound leaves the larynx it travels down the trachea and then divides when the airway divides. Some sound must be transmitted through the lung parenchyma but most travels down the airway. Eventually the sound travels along airways of different lengths and therefore becomes out of phase. Next it arrives in the respiratory bronchioles and alveoli and then gets transmitted through the chest wall to your stethoscope. The fat layer filters out much of the high frequency sound (above 4 kHz). The resulting sounds are much softer (because the sound has effectively been diluted throughout the whole of the lungs). There is no gap between inspiration and expiration (because all of the sound has become out of phase and therefore 'filled in' the gap. Finally, the first third of expiration is now the only part that is audible because the latter two-thirds are much quieter.

Reference: Chamberlain

Bronchiectasis

 Bronchiectasis is derived from Greek roots, bronchion meaning windpipe and ektasis is stretching out.

Bronchiectasis is present when one or more Bronchi are abnormally and permanently dilated.

Reference: Crofton and Douglas page 794

Bronchiectasis is an entity characterized pathologically by airway inflammation and permanent bronchial dilatation 

Clinically by cough,sputum production,and exacerbations with recurrent respiratory tract infections.

Reference: Fishman edition 6 page no 862

Drugs causing breathlessness

 DRUGS CAUSING ORGANISING PNEUMONIA

1.Amiodarone

2.Amphotericin B

3.Carbamazepine

4.Cephalosporins

5.Coacine

6.Gold salts

7.Interferon alpha

8.Minocycline

9.Nitofurantoin

11.D-Penicillamine

12.Phenytoin

13.Rituximab

14.Sotalol

15.Sulfasalazine/Mesalamine

DRUGS CAUSING INTERSTITIAL INFILTRATES/FIBROSIS:

1.Amiodarone

2.Beta adrenargic blockers

3.Carbamazepine

4.Gold salts

5.Hydralazine

6.Methotrexate

7.Penicillins

EOSINOPHILIC LUNG DISEASE

1.ACE inhibitors

2.Amiodarone

3.Amphotericin B

4.Carbamazepine

5.Cephalosporins

6.Erythromycin

7.Ethambutol

8.Isoniazid

9.Minocycline

10.Methotrexate

11.Nitofurantoin

12.NSAIDS

13.PAS

14.Tetracycline

15.Trazadone