COPD

Definition

Chronic obstructive pulmonary disease (COPD) is defined as a disease state characterized by airflow limitation that is not fully reversible

Suspected when age>40/50

It includes emphysema and chronic bronchitis

Emphysema((Abnormal permanent dilatation of airways distal to terminal bronchiole without obvious fibrosis)

           Pink puffers(emphysema is more predominant than chronic bronchitis)

           Thin ,non cyanotic ,normal PaCO2 until end stage 

           Types-Centriacinal(Smoker) ,panacinar(Alpha 1 anti trypsin deficiency)   

            
             Chronic bronchitis

                        Blue bloaters(Chronic bronchitis is  more predominant than emphysema)

                        Fatty ,cyanotic ,early PaCO2 rise

Etiology

1.Cigarette smoking

2.Occupational-Silicon ,jute factory

3.Alpha 1 anti trypsin deficiency

Pathogenesis

Dust inhaled>Chronic irritation>Goblet hypertrophy/plasia>Increased mucous secretion>Inflammation>Edema>Narrowing of airway>Bulla>(+Anti trypsin)>Disrupted alveoli>Hypoxia

(If Hypoxia>Increased erythropoietin>Increased RBC>Secondary polycythemia>Urea production>Gout)

[COPD-Permanent narrowing

Asthma-Reversible narrowing]

Cor pulmonale

Right ventricular hypertrophy(RVH)  with/without failure due to pulmonary hypertension due to diseases of lung parenchyma or its vasculature or (Pectus excavatum)chest wall

Mechanism-

Alveoli ruptured>Decreased capillary bed and hypoxia>Vasoconstriction>Pulmonary hypertension>RVH>Regurgitation>Right ventricular failure

When there is RVH-Left parasternal heave,epigastric pulse ,palpable p2 is found

Clinical feature

1.Age-Middle/elderly ,usually after 50

2.Sex-M>F(Except rangpur)

3.Onset-Gradual(Starts as  productive winter cough which gradually increases in severity and duration on subsequent years until present throughout the year.Initially exertional dyspnoea ,then progresses)

4.H/O smoking(Minimum 10 pack years)

[ 1 pack year=20 sticks/day for 1 year]

Typical presentation of COPD

Productive cough for most of the days in a month for 3 consequetive months for at least 2 successive years(Chronic bronchitis)

General physical examination

Early-Asymptomatic

Late-

        Appearance-Respiratory distress ,accessory muscle are prominent

                 Cyanosis

                    Raised JVP(RVF)

                      Enlarged tender liver(If RVF)

                         Leg edema(Failure to excrete salt/water by hypoxic hypercapnoeic kidney)

                           Warm hand(If respiratory failure hypercapnoea )

                              Full bounding pulse(If respiratory failure)

Local examination of Respiratory system

1.Inspection-

Respiratory distress ,barrel chest ,indrawing of supraclavicular-intercostal-subcostal spaces

Hoover's sign-In severe case paradoxical inward movement of rib cage with inspiration

2.Palpation

Vocal fremitus-Decreased

Expansibility-Decreased

Trachea-Normal

Enlarged tender soft liver and ascitis[If Cor>RVF>Congested liver>Jaundice]

3.Percussion

Hyper resonant

(Upper border liver dullness below 5th space and diminished superficial cardiac dullness(If emphysema) [If one is +ve and other is -ve ,it is pneumothorax]

4.Auscultation

Breath sound-Vesicular with prolonged expiration

Added sound-Ronchi

Pleural rub-No

Crepitation-May be present

Differential diagnosis

Bronchial asthma

TB

Heart failure

Bronchiectasis

Complication

1.Cor pulmonale(Check if RVH and percussion)

2.Pneumothorax

3.Secondary polycythemia(Red dusky conjunctiva)

4.Type 2 respiratory failure(When hypoxia with hypercapnoea present , Blood gas analysis shows PaCO2 >50mmHg ,which should be normally 35-40mmHg)

Features of hypercapnoea

Prominent eyeball , red conjunctiva ,warm extremity ,full bounding pulse  ,flapping tremor

Investigation

FBC with TC DC WBC(polycythemia) , raised PCV ,reduced ESR

Chest X ray PA view

              Low flat diaphragm

              Horizontal rib

              Tubular heart shadow

              Widening of intercostal spaces

              More Translucent lung with bulla

Lung function test

               Decreased PEFR(500-600fm) [It is bed side test]

               Spirometry-FEV1 <70% ,FEV1/FVC ratio also reduced

               Reversibility test -ve

Sputum for AFB

Arterial Blood gas analysis

ECG ,Echo

Serum Alpha 1 anti trypsin(Young ,non smoker)

Post bronchodilator FEV1 classification

Mild-FEV1 <80%

Moderate-FEV1 50-79%

Severe-FEV1 30-49%

Very severe-FEV1 <30%

[With FEV1/FVC ratio <70% for all the above]

Treatment

1.Avoid smoking

2.Propped up position

3.O2 in low dose & continuous(?)-[In prolonged hypercapnoea ,patient gets insensitive to PaCO2 ,only depends on hypoxia for respiration.High dose O2 corrects hypoxemia ,leaving to chemical factor to drive respiratory centre causing respiratory arrest and apnoea.Thereby further rise in CO2 leading to CO2 necrosis. So 24-28% O2 is to given by venturi mask.Correct PaO2 at <60mmHg as hypoxic drive is withdrawn if PaO2 >60mmHg]

4.Cephalosporin

5.Inhaled bronchodilator and steroid

6.Diuretics if edema

7.Breathing exercise to cough out secretions

8.LTOT/domiciliary oxygen-

            2-4L O2/hr in 15 hrs in a day for life long to prevent pulmonary hypertension ,cor pulmonale

            Indication-PaO2 <7.3 kPa ,OR ,> 7.3 kPa with PTN  

[1L O2 raises 4% O2 saturation]