Airway DiseasesMay 2013

Mekelle

Chronic Obstructive Pulmonary Disease

COPD

Definition

COPD- a disease state characterized by airflow limitation that is not fully reversible

The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases

COPD includes Chronic bronchitis

Emphysema

Small airway disease

COPD is the fourth leading cause of death in the USA

Risk factors

In the west

Most important is cigarette smoking

In developing countries

Role of household fuels and indoor pollution have important contribution.

Occupational exposure

Air Pollution

Genetic- α-1 Antitrypsin Deficiency

Regarding smoking

The degree of damage to the lung (FEV loss) is proportional to the amount of cigarettes smoked.

Not all smokers develop COPD ( 15%) only; outlining individual susceptibility

Second hand (passive) smokers are also at risk

Regarding asthma and COPD

Dutch hypothesis – asthma and COPD are two diseases in the same spectrum

British hypothesis – different entities

Natural history

Risk of mortality from COPD is closely associated with reduced levels of FEV1

FEV1 is a marker of obstruction

Obstruction leads to hyperinflation.

Hyperinflation leads to impaired diaphragmatic function.

Pathology Cigarette smoke exposure may affect

the large airways, small airways ( 2 mm diameter), and alveolar space

Large airway changes cause cough and

sputum (i.e. the symptoms),

small airways and alveolar changes are responsible for physiologic alterations

Patterns

Emphysema

Defined in anatomic terms

Destruction of the airways

Pan or centri acinar pattern

Chronic bronchitis

Defined in clinical terms

Based on symptoms

Diagnosis Consider COPD in any patient with combination of

these symptoms

Dyspnea

Chronic cough

Chronic sputum production

History of exposure to risk factors

Physical examination is rarely diagnostic in COPD Wheezes here and there

With severe airflow obstruction- use of accessory muscles of respiration- tripod

position

Cyanosis

Systemic wasting Later on

Signs of right sided heart failure

Sometimes Features of systemic inflammation ( ischemic

heart disease osteoporosis ….), poor sleep

Laboratory findings

CXR can be normal or some times shows some hyperinflation. Don’t rule out COPD b/c you have a normal CXR

Pulm Function tests

Low FEV1/FVC

Low peak flow

Some reversibility might be there in the obstruction

Hct – for erythrocytosis

ECG and Echo – for Cor pulmounale

Stage of COPD

We use spirometric parameters

GOLD staging

Management plan has four components

Assess and monitor disease

Reduce risk factors

Manage stable COPD

Manage exacerbations

Assess and monitor

Stage of the disease

Use spirometry and clinical features

Risk factor reduction

Smoking cessation

Stable COPD

Bronchodilators – anticholinergics, beta agonist

Inhaled corticosteroids- for patients with frequent exacerbations

Vaccination- influenza and pnuemococcal

Non pharmacotherapies- pulmonary rehabilitation, lung volume reduction surgery, lung transplantation

Treatment of exacerbations Exacerbations are a prominent feature of

the natural history of COPD The frequency of exacerbations increases

as airflow obstruction increases Exacerbations are commonly considered to

be episodes of increased dyspnea and cough and change in the amount and character of sputum

Infections- bacteria most common cause of exacerbation

Treatment includes-

Bronchodilators

Antibiotics

Glucocorticoids

Oxygen therapy

Mechanical ventilation

Home O2 therapy for resting and nocturnal hypoxemia

Lung volume reduction surgery

Asthma

Asthma

Asthma is a syndrome characterized by airflow obstruction that varies markedly, both spontaneously and with treatment

Narrowing of the airways is usually reversible, but in some patients with chronic asthma there may be an element of irreversible airflow obstruction

Prevalence

~10–12% of adults and 15% of children affected by the disease

can present at any age

peak age is 3 years

Children with asthma – the asthma can subside as they grow older.

Adults with asthma-rarely so

The severity of asthma does not vary significantly within a given patient

Etiology

Asthma is a heterogeneous disease with interplay between genetic and environmental factors

Genetic predisposition suggested by- familial association of asthma

high degree of concordance for asthma in identical twins

The severity of asthma is also genetically determined

Environmental factors-in early life determine which atopic individuals become asthmatic

Atopy is the major risk factor for asthma Allergic rhinitis and atopic dermatitis

Allergens House dust mite

Intrinsic Asthma or nonatopic asthma-~10% have negative skin test to common inhalant allergens and normal serum concentrations of IgE

Usual adult onset

Pathogenesis Asthma is associated with a specific

chronic inflammation of the mucosa of the lower airways

The degree of inflammation is poorly related to disease severity and may be found in atopic patients without asthma symptoms

Clinical features

Wheezing,

dyspnea, and

Cough

These are variable, both spontaneously and with therapy

Symptoms may be worse at night

Typical physical signs are inspiratory, and to a great extent expiratory, rhonchi throughout the chest

Physical signs

wheezes

Diagnosis

Simple spirometry confirms airflow limitation with a reduced FEV1,

FEV1/FVC ratio,

PEF

Reversibility is demonstrated by a >12% or 200 mL increase in FEV1 15 min after an inhaled short-acting beta 2-agonist or, in some patients, by a 2- to 4-week trial of oral glucocorticoids

methacholine or histamine challenge –rarely needed to confirm airway hyperresponsiveness

Aims of treatment

For the patient to have

No or minimal symptoms esp. nocturnal

No emergency OPD visits

No frequent use of salbutamol

No limitation of activity

Treatment

Two groups of drugs are used

Bronchodilators beta 2-adrenergic agonists,

anticholinergics, and

theophylline

Controllers Glucocorticoids

Antileukotriens

Cromones

antiIGE

Immunotherapy

Management of chronic asthma

Avoid triggers

Pharmacotherapy –stepwise therapy

Patient education

Goals

Reduce impairment

Reduce risk

no cure but symptoms can be controlled

Treatment of chronic asthma

First try to determine severity.

This can be done by looking at Reported symptoms over the previous two to four weeks

Night symptoms

Current level of lung function (FEV1 and FEV1/FVC values)

Number of exacerbations requiring oral glucocorticoids per year

Emergency visits

Then stratify your patient by the severity to either

Intermittent

Mild persistent

Moderate persistent

Severe persistent

Then institute therapy by the level of severity

Adjusting therapy

Assess the status of the patient after 2-4 weeks of therapy.

If improving step down the treatment

If not step up the ladder.

Management of acute severe asthma

The best strategy for management of acute exacerbations of asthma is early recognition and intervention, before attacks become severe and potentially life threatening

Treatment starts with assessment of severity of attack

Look for simple clinical severity indicators

Degree of dyspnea

Can the patient finish a sentence?

Degree of desaturation?

Paradoxic breathing, accessory muscles

Mental status

Silent chest

Level of V/S derangement

Provide

High flow oxygen therapy to keep oxygen saturation >90%

High dose inhaled short acting beta agonists are the main stay of therapy (nebulized or via metered dose inhaler)

Add inhaled anticholinergics if no adequate response

Start systemic glucocorticoids if there is not an immediate and marked response to the inhaled short-acting beta agonists

Slow infusion of aminophylline may be effective in patients not responding to high dose bronchodilators

Make frequent (every one to two hours) objective assessments of the response to therapy until definite, sustained improvement is documented

For patients with respiratory failure, it is necessary to intubate and institute ventilation

Consider antibiotics if signs of pneumonia

Refractory asthma

A small proportion of patients (~5% of asthmatics) are difficult to control despite maximal inhaled therapy

Some of these patients will require maintenance treatment with oral corticosteroids

The most common reason for poor control of asthma is noncompliance with medication